:  Oct 22, 2004



4.0 Liter Electronic Engine Controls Component Location Sheet 1 of 2



1  - Mass air flow/ inlet air temperature sensor (MAF/IAT)
2  - Inlet manifold tuning valve (IMTV)
3  - Camshaft position sensor (CMP)
4  - Crankshaft position sensor (CKP)
5  - Engine oil temperature sensor
6  - Knock sensor
7  - Ignition coils
8  - Heated Exhaust Gas Oxygen sensor (HEGO)
9  - Universal Heated Exhaust Gas Oxygen sensor (UHEGO)
10  - Heated Exhaust Gas Oxygen sensor (HEGO)
11  - Universal Heated Exhaust Gas Oxygen sensor (UHEGO)
12  - Injectors
13  - Knock sensor
14  - Spark plugs
15  - Engine oil pressure sensor
16  - Exhaust Gas Reticulation (EGR) valve and pressure differential sensor
17  - Electric throttle

4.0 Liter Electronic Engine Controls Component Location Sheet 2 of 2



1  - Main relay
3  - Transfer box control module
2  - ECM
4  - Brake lamp switch
5  - clutch switch
6  - ABS control module

4.0L EMS Control Diagram Sheet 1 of 2

:
  A= Hardwired



1  - Main relay
2  - Crankshaft position sensor (CKP sensor)
3  - Camshaft position sensor (CMP sensor)
4  - Engine coolant temperature sensor (ECT)
5  - Accelerator pedal
6  - Mass air flow meter (MAF)
7  - Engine oil temperature sensor
8  - Manifold absolute pressure sensor (MAP)
9  - Brake light switch
10  - Knock sensor
11  - Fuse No 25P
12  - ECM
13  - Fuse 60P
14  - Ignition switch
15   Fuseable link 11E

4.0L EMS Control Diagram Sheet 1 of 2

:
  A= Hardwired D= CAN Bus



1  - Injectors
2  - Engine cooling fan
3  - Inlet manifold tuning valve (IMTV)
4  - ABS control module
5  - Instrument cluster
6  - Transmission Control Module (TCM)
7  - Restraints control module
8  - Differential control module
9  - Transfer box control module
10  - Electric park brake control module
11  - Automatic temperature control module (ATCM)
12  - Universal Heated Exhaust Gas Oxygen sensor (UHEGO) and Heated Exhaust Gas Oxygen sensor (HEGO)
13  - Ignition coils
14  - Universal Heated Exhaust Gas Oxygen sensor (UHEGO) and Heated Exhaust Gas Oxygen sensor (HEGO)
15  - Generator
16  - ECM
17  - EGR valve/ differential pressure sensor
18  - Clock spring
19  - Cruise control switches
20  - Electric throttle body

GENERAL

The V6 4.0 Liter engine is controlled by a Engine Control Module (ECM) manufactured by DENSO. The Engine Management System (EMS) controls the following:

ENGINE CONTROL MODULE (ECM)



The ECM is located in the E-Box in the plenum area on the passenger side of the engine compartment attached to the bulkhead.

Inputs

The ECM has the following inputs:

Outputs

The ECM outputs to the following:

The ECM controls the engine fuelling by providing sequential fuel injection to all cylinders. Ignition is controlled by a direct ignition system, provided by six plug top coils. The ECM is able to detect and correct for ignition knock on each cylinder and adjust the ignition timing for each cylinder to achieve optimum performance.

The ECM uses a torque-based strategy to generate the torque required by the driver and other vehicle ECU's. The EMS uses various sensors to determine the torque required from the engine. These include:

The EMS processes these signals and decides how much torque to generate. Torque is then generated by using various actuators to supply air, fuel and spark to the engine (electronic throttle, injectors, coils, etc.)The EMS also interfaces with other vehicle ECU's, via CAN, to obtain additional information, these include

Pin No Description Input/Output
1 CAN Input/Output
2 CAN Input/Output
3 Generator monitor Input
4 UHEGO Bank A ground -
5 UHEGO Bank B ground -
6 Crank sensor - Input
7 Cam sensor ground -
8 NC -
9 NC -
10 Sensor ground 3 -
11 Sensor ground 4 -
12 Sensor ground 5 -
13 NC -
14 Spare ground -
15 Sensor ground 6 -
16 NC -
17 NC -
18 MAF ground -
19 Knock sensor bank A ground -
20 Knock sensor bank B ground -
21 NC -
22 NC -
23 Oil temperature sensor Input
24 Sensor power 6 Output
25 LIN A Output
26 UHEGO B + Input
27 UHEGO B - -
28 UHEGO A + +
29 UHEGO A - -
30 Crank sensor + Input
31 NC -
32 NC -
33 NC -
34 CMP signal bank A Input
35 NC -
36 NC -
37 NC -
38 Differential pressure sensor Input
39 NC -
40 Fuel pressure sensor Input
41 NC -
42 Knock sensor A + Input
43 Knock sensor B + Input
44 NC -
45 NC -
46 Fuel temperature sensor Input
47 Sensor power 5 Output
48 Sensor power 4 Output
49 NC -
50 NC -
51 NC -
52 NC -
53 NC -
54 NC -
55 NC -
56 Ignition coil cylinder 3 B Output
57 Ignition coil cylinder 3 A Output
58 Ignition coil cylinder 2 B Output
59 Ignition coil cylinder 2 A Output
60 Ignition coil cylinder 1 B Output
61 Ignition coil cylinder 1 A Output
62 Ignition coil ground bank A -
63 Viscous fan monitor Input
64 Ignition coil ground bank B -
65 Throttle position sensor 1 -I
66 Air temperature sensor Input
67 Throttle position sensor 2 Input
68 Coolant temperature sensor Input
69 MAP Input
70 MAF Input
71 NC -
72 Sensor power 3 Output
73 NC -
74 Throttle valve open direction - Output
75 Throttle valve open direction + Output
76 UHEGO Heater bank A Output
77 UHEGO Heater bank B Output
78 Injector cylinder 1 B Output
79 Injector cylinder 1 B Output
80 Injector cylinder 2 A Output
81 Injector cylinder 2 B Output
82 Injector cylinder 3 A Output
83 Injector cylinder 3 B Output
84 Inlet manifold tuning valve 1 Output
85 NC -
86 NC Output
87 NC Output
88 NC Output
89 NC -
90 EGR Input
91 NC -
92 Purge valve Output
93 Viscous fan request Output
95 Fuel pump relay Output
96 Alternator control Output

ECM Connector C0635 Pin Out Table

Pin No Description Input/Output
1 Signal ground 1 -
2 Power ground 1 -
3 Power ground 2 -
4 ECM power Input
5 Power ground 3 -
6 APP sensor ground 1 -
7 APP sensor ground 2 -
8 NC -
9 NC -
10 NC -
11 NC -
12 Park/ Neutral signal Input
13 NC -
14 NC -
15 NC -
16 EMS relay Output
17 Crank request Output
18 CAN + Output
19 APP sensor 2 power Output
20 Fuel pump control Output
21 NC -
22 NC -
23 NC -
24 APP sensor 1 signal Output
25    
26 Brake light switch Input
27 NC -
28 NC -
29 NC -
30 Ignition switch Input
31 CAN + Input
32 APP sensor 1 power Output
33 DMTL Output
34 NC -
35 Cruise switch - Output

ELECTRONIC THROTTLE



The V6 engine torque is regulated via an electronic throttle body which is located on the intake manifold in the engine compartment. An Accelerator Pedal Position sensor (APP) determines the driver demand to control throttle opening. This value is input into the EMS and the throttle is opened to the correct angle by means of an electric motor integrated into the throttle body. Sensors in the throttle body are used to determine the position of the throttle plate and the rate of change in its angle. A software strategy within the ECM enables the throttle position to be calibrated each ignition cycle. When the ignition is turned 'ON', the ECM opens and closes the throttle fully, thus performing a self-diagnostic and calibration. The throttle body is connected to the ECM via a pair of twisted wires to avoid electrical interference.   Acceleration Control (310-02A Acceleration Control - 4.0L)


C0175 Electronic Throttle Pin Out Table

Pin No Description Input/Output
1 Signal 1 Output
2 5 volt supply Input
3 Signal 2 Output
4 Ground -
5 Actuator + Input
6 Actuator - -

ACCELERATOR PEDAL POSITION SENSOR (APP)



The Accelerator Pedal Position Sensor (APP) is used in conjunction with the Electronic Throttle Body to provide a drive-by-wire system. The sensor is a resistive type. Sensors in the accelerator pedal are used to determine the driver's request for vehicle speed, acceleration and deceleration. This value is input into the EMS and the throttle is opened to the correct angle by means of an electric motor integrated into the throttle body.

The APP sensor signals are checked for range, and for plausibility. Two separate reference voltages are supplied to the pedal. If one sensor fails, the other can be used as a 'limp – home' input.

The wires that connect the ground and signal from both potentiometers to the EMS are twisted together into two pairs, avoiding having to use a screen wire.

If signal failure occurs, the ECM enters limp home mode. The APP Sensor is located at the accelerator pedal .

C0787 APP Sensor Connector Pin Out Table

Pin No Description Input/Output
1 Sensor 2 ground -
2 Sensor 1 demand Output
3 Sensor 1 ground -
4 NC -
5 Sensor 2 demand Output
6 Supply 2 5 volt Input
7 Supply 1 5 volt Input
8 NC -

OXYGEN SENSORS

Oxygen Sensor-Upstream



Oxygen Sensor-Downstream



There are four oxygen sensors located in the exhaust system. Two upstream (UHEGO) before the catalytic converter and two down stream (HEGO) after the catalytic converter. The sensors monitor the level of oxygen in the exhaust gases and is used to control the fuel/air mixture. Positioning a sensor in the stream of exhaust gasses from each bank enables the ECM to control the fuelling on each bank independently of the other, allowing much closer control of the air / fuel ratio and catalyst conversion efficiency.

The Oxygen Sensor needs to operate at high temperatures in order to function correctly. To achieve the high temperatures required, the sensors are fitted with heater elements that are controlled by a PWM signal from the ECM. The heater elements are operated immediately following engine start and also during low load conditions when the temperature of the exhaust gases is insufficient to maintain the required sensor temperatures. A non-functioning heater delays the sensor’s readiness for closed loop control and influences emissions. The PWM duty cycle is carefully controlled to prevent thermal shock to cold sensors.

UHEGO (Universal Heated Exhaust Gas Oxygen) sensors also known as Linear or "Wide Band" sensors produces a constant voltage, with a variable current that is proportional to the oxygen content. This allows closed loop fuelling control to a target lambda, i.e. during engine warm up (after the sensor has reached operating temperature and is ready for operation). This improves emission control.

The HEGO sensor uses Zirconium technology that produces an output voltage dependant upon the ratio of exhaust gas oxygen to the ambient oxygen. The device contains a Galvanic cell surrounded by a gas permeable ceramic, the voltage of which depends upon the level of O2 defusing through. Nominal output voltage of the device for l =1 is 300 to 500m volts. As the fuel mixture becomes richer (l<1) the voltage tends towards 900m volts and as it becomes leaner (l>1) the voltage tends towards 0 volts. Maximum tip temperature is 1,000 Degrees Celsius for a maximum of 100 hours.

Sensors age with mileage, increasing their response time to switch from rich to lean and lean to rich. This increase in response time influences the ECM closed loop control and leads to progressively increased emissions. Measuring the period of rich to lean and lean to rich switching monitors the response rate of the upstream sensors.

Diagnosis of electrical faults is continually monitored in both the upstream and downstream sensors. This is achieved by checking the signal against maximum and minimum threshold, for open and short circuit conditions.

Oxygen sensors must be treated with the utmost care before and during the fitting process. The sensors have ceramic material within them that can easily crack if dropped / banged or over-torqued. The sensors must be torqued to the required figure, (40-50Nm), with a calibrated torque wrench. Care should be taken not to contaminate the sensor tip when anti-seize compound is used on the thread.

Failure Modes Failure Symptoms It is possible to fit front and rear sensors in their opposite location. However the harness connections are of different gender and colour to ensure that the senors cannot be incorrectly connected. In addition to this the upstream sensors have two holes in the sensor tip, whereas the down stream sensors have four holes in the sensor tip for the gas to pass through.

KNOCK SENSORS



The ECM uses active knock control, which serves to prevent engine damaging pre-ignition or detonation under all operating conditions enabling the engine to operate without additional safety margins. For the ECM to be able to determine the point at which a cylinder is pre-detonating, 2 piezo-ceramic sensors are mounted on the engine block. Each sensor monitors engine knock by converting the engine block noise into a suitable electrical signal, which is then transmitted back to the ECM via a twisted pair cable. The signal is then processed within the ECM to identify the data that characterises knocking.

This information is compared to known signal profiles to determine whether knock is present. If so, the closed loop control system then retards the ignition on that cylinder, for a number of cycles, after which it gradually moves back towards its original setting.

Failure Symptoms

The following describes the failure symptoms of the knock sensors:

One sensor is located in the centre of the engine valley and the other is located on the front RH side of the cylinder block.

CRANKSHAFT SPEED AND POSITION SENSOR



The Crankshaft Position Sensor (CKP) is located on the top of the transmission bell housing just to the left of the centre line with the sensor tip adjacent to the flywheel rim. The sensor is a variable reluctance type with a resistance of 1100 Ohms +- 150 Ohms.

The sensor produces the signal which enables the ECM to determine the angle of the crankshaft, and the engine RPM. From this, the point of ignition, fuel injection, etc. is calculated. If the signal wires are reversed a 3° advance in timing will occur, as the ECM uses the falling edge of the signal waveform as its reference / timing point for each tooth.

The sensor picks up its signal from a reluctor ring machined into the diameter of the drive plate. The reluctor ring has 36 teeth at 10° intervals and 3° wide. One of the teeth is removed to provide a reference mark which is 60 degrees BTDC No.1 cylinder.

The sensor operates by generating an output voltage caused by the change in magnetic field that occurs as the teeth pass in front of the sensor. The output voltage varies with the speed of the teeth passing the sensor. The higher the engine speed, the higher the output voltage.

The ECM transmits the engine speed over the CAN bus.

If the CKP sensor fails while the engine is running the engine will stall, misfire or run poorly and a relevant fault code will be stored. If the engine is not running when a fault occurs then the engine will not start.

CAMSHAFT POSITION SENSOR (CMP)



The Camshaft Position Sensor (CMP) is a variable reluctance type sensor located at the front of the engine in the valve cover above number 4 cylinder.

The CMP sensor produces one pulse for every two engine revolutions. The sensor picks up on a reluctor on the LH camshaft.

ENGINE COOLANT TEMPERATURE SENSOR



The Engine Coolant Temperature sensor (ECT) is a Negative Temperature Coefficient (NTC) type sensor. As coolant temperature rises the resistance of the sensor falls.

The sensor is located at the front of the engine behind and below the throttle body.

Should the sensor fail the ECM use the oil temperature sensor signal as a backup coolant temperature signal.

ENGINE OIL TEMPERATURE SENSOR



Oil temperature is monitored through a level sensor mounted in the engine sump.

The sensor operates in the range -40 TO 150 degrees Celsius.

MASS AIR FLOW /INLET AIR TEMPERATURE SENSOR (MAF/IAT)



The MAF and IAT sensor is located in the air duct between the air filter and throttle body.

The air mass flow is determined by the cooling effect of inlet air passing over a “hot film” element contained within the device. The higher the air flow the greater the cooling effect and the lower the electrical resistance of the element. The signal from the device is then calculated by the ECM to determine the Air Mass Flow into the engine.

The measured air mass flow is used in determining the fuel quantity to be injected in order to maintain the stichometric air/fuel mixture required for correct operation of the engine and exhaust catalysts. Should the device fail there is a software backup strategy that will be evoked once a fault has been diagnosed.

The Inlet Air Temperature (IAT) sensor is integrated into the Mass Air Flow meter. It is a temperature dependent resistor (thermistor), i.e. the resistance of the sensor varies with temperature. This thermistor is a negative temperature coefficient (NTC) type element meaning that the sensor resistance decreases as the sensor temperature increases. The sensor forms part of a voltage divider chain with an additional resistor in the ECM. The voltage from this network changes as the sensor resistance changes, thus relating the air temperature to the voltage measured by the ECM.

The fixed default value for air temperature is 35°C

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR



The MAP sensor provides a voltage proportional to the absolute pressure in the intake manifold.

This signal allows the load on the engine to be calculated and used within the internal calculations of the ECM.

The sensor is located in the EGR valve at the front LH side of the engine.

DIFFERENTIAL PRESSURE FEEDBACK-ELECTRONIC/MANIFOLD ABSOLUTE PRESSURE SENSOR (DPFE/MAP)

This pressure transducer monitors the pressure differential on either side of an orifice in the EGR system flow path and transmits that information to the ECM. The pressure drop measured across this orifice is used to estimate the flow rate of recirculated exhaust gas. An Electronic Vacuum Regulator (EVR) is used to control the vacuum signal to the EGR valve based on the electrical signal from the ECM. The ECM monitors the EGR level based on the feedback from the DPFE/MAP transducer, which creates a closed loop system.

EXHAUST GAS RETICULATION VALVE (EGR)

The EGR (exhaust gas recirculation) Valve is a PWM controlled valve that allows burned exhaust gas to be recirculated back into the engine. Since exhaust gas has much less oxygen than air, it is basically inert. It takes the place of air in the cylinder and reduces combustion temperature. As the combustion temperature is reduced, so are the oxides of nitrogen (NOx) emissions.

CRUISE CONTROL SWITCHES



1   On/Suspend/Off Switch
2   Resume/Accelerate/Decelerate (+/–) Switches
3   Active cruise control time gap switches (for future release)
4   Clock spring
5   Wiper control column switch

The V6 ECM incorporates a cruise control function. Active Cruise Control (ACC) is also an option. The EMS uses a set of resistive ladders to interface with the driver cruise control requirements. The cruise control is operated from the steering wheel mounted switches. There are three illuminated rocker switches on a resistive ladder.   Speed Control (310-03A Speed Control)


The cruise control does not have a master switch, it is enabled by pressing the set switch.

GENERATOR



The Generator has a multi function voltage regulator for use in a 14V charging system with 6÷12 zener diode bridge rectifiers.

The ECM monitors the load on the electrical system via PWM signal and adjusts the generator output to match the required load. The ECM also monitors the battery temperature to determine the generator regulator set point. This characteristic is necessary to protect the battery; at low temperatures battery charge acceptance is very poor so the voltage needs to be high to maximise any recharge ability, but at high temperatures the charge voltage must be restricted to prevent excessive gassing of the battery with consequent water loss.   Generator (414-02A Generator and Regulator - 4.0L)


The Generator has a smart charge capability that will reduce the electrical load on the Generator reducing torque requirements, this is implemented to utilise the engine torque for other purposes. This is achieved by monitoring three signals to the ECM:

FUEL INJECTORS



The ECM controls six fuel injectors located on the cylinder head. The injectors are fed from a common fuel rail as part of a ‘return less’ fuel system.

Fuel rail pressure is constant at 4.5 bar (59 psi) and is regulated by a regulator that is integral to the fuel pump module. The ECM monitors the output power stages of the injector drivers for electrical faults. The injector has a default resistance of 14.5 Ohms at 20 Degrees Celsius.   Fuel Charging and Controls (303-04A Fuel Charging and Controls - 4.0L)


SPARK PLUGS

It is essential that only factory-approved spark plugs be used in service. DO NOT attempt to use ‘equivalent’ spark plugs. Use of unapproved spark plugs may cause the misfire detection system to malfunction, and the ECM to store misfire faults.

IGNITION COILS



The Land Rover V6 engine is fitted with ignition coils that are driven directly by the ECM. The coils are mounted on top of the inlet manifold and are connected to the spark plugs by High Tension (HT) leads. The positive supply to the coil is fed from fuse 19 in the Battery Junction Box (BJB). Each coil contains a power stage to trigger the primary current. The ECM sends a signal to each of the coils power stage to trigger the power stage switching. Each bank has a feedback signal that is connected to each power stage. If the coil power stage fails the feedback signal is not sent, causing the ECM to store a fault code.

FUEL PUMP RELAY

The V6 engine has a return less fuel system. The system pressure is maintained at a constant 4.5 bar , with no reference to intake manifold pressure. The fuel is supplied to the injectors from a fuel pump located within the fuel tank. The electrical supply to this fuel pump is controlled by the ECM via the fuel pump relay, in the event of a vehicle impact the ECM will receive a crash signal from the restraints control module and will cut the power supply to the fuel pump relay. The fuel system is pressurised as soon as the ECM is powered up, the pump is then switched off until engine start has been achieved.

The fuel pump relay is located in the Central Junction Box (CJB). The Fuel pump is contained within the fuel tank.   Fuel Tank and Lines (310-01A Fuel Tank and Lines - 4.0L)


VISCOUS FAN CONTROL

The ECM controls an electronically controlled viscous coupled fan to provide engine cooling. The ECM supplies the fan with a PWM signal that controls the amount of slippage of the fan, thus providing the correct amount of cooling fan speed and airflow. The EMS uses a Hall Effect sensor to determine the fan speed.

STARTER RELAY

The starter relay is supplied with power from fuseable link 19 in the Battery Junction Box.

The ECM controls the starter relay by supplying a 12 volt signal to the relay coil when the ignition is in crank position. This relies on the transmission gear position being either P or N.

CONDENSER FAN CONTROL

The ECM receives CAN messages from the ATC control module for idle speed adjustment and for cooling fan.

AirConCoolingRequest

This signal defines the level of cooling (from engine cooling fan(s)) required by the ATC system. Calibration within the EMS determines the fan speed required, and which fans will be used, at each requested level.

AirConIdleSpeedRequest

This signal defines whether or not an increase in the engine idle speed is required by the ATC system. The amount of idle speed increase is defined in the EMS calibration.

INTAKE MANIFOLD TUNING VALVE (IMTV)



The Intake Manifold Tuning Valve (IMTV) moves a plate within the inlet manifold to allow or block sonic pulses between the split manifold halves. This, in effect, extends the inlet tracts for better low rpm torque. The IMTV is a two position valve and is either fully open or fully closed.   Intake Air Distribution and Filtering (303-12A Intake Air Distribution and Filtering - 4.0L)


ECM ADAPTIONS

The ECM has the ability to adapt the values it uses to control certain outputs. This capability ensures the EMS can meet emissions legislation and improve the refinement of the engine throughout its operating range.

The components which have adaptions associated with them are:



UHEGO/HEGO and MAF/IAT Sensor

There are several adaptive maps associated with the fuelling strategy. Within the fuelling strategy the ECM calculates short-term adaptions and long term adaptions. The ECM will monitor the deterioration of the HO2S over a period of time. It will also monitor the current correction associated with the sensors.

The ECM will store a fault code in circumstances where an adaption is forced to exceed its operating parameters. At the same time, the ECM will record the engine speed, engine load and intake air temperature.

CKP Sensor

The characteristics of the signal supplied by the CKP sensor are learned by the ECM. This enables the ECM to set an adaption and support the engine misfire detection function. Due to the small variation between different flywheels and different CKP sensors, the adaption must be reset if either component is renewed, or removed and refitted. It is also necessary to reset the flywheel adaption if the ECM is renewed or replaced. The ECM supports four flywheel adaptions for the CKP sensor. Each adaption relates to a specific engine speed range. The engine speed ranges are detailed in the table below:

Adaptions Engine Speed, rev/min
1 1800 - 3000
2 3001 - 3800
3 3801 - 4600
4 4601 - 5400

Misfire Detection

Legislation requires that the ECM must be able to detect the presence of an engine misfire. It must be able to detect misfires at two separate levels. The first level is a misfire that could lead to the vehicle emissions exceeding 1.5 times the Federal Test Procedure (FTP) requirements for the engine. The second level is a misfire that may cause catalyst damage.

The ECM monitors the number of misfire occurrences within two engine speed ranges. If the ECM detects more than a predetermined number of misfire occurrences within either of these two ranges, over two consecutive journeys, the ECM will record a fault code and details of the engine speed, engine load and engine coolant temperature. In addition, the ECM monitors the number of misfire occurrences that happen in a 'window' of 200 engine revolutions. The misfire occurrences are assigned a weighting according to their likely impact on the catalysts. If the number of misfires exceeds a certain value, the ECM stores catalyst-damaging fault codes, along with the engine speed, engine load and engine coolant temperature.

The signal from the crankshaft position sensor indicates how fast the poles on the flywheel are passing the sensor tip. A sine wave is generated each time a pole passes the sensor tip. The ECM can detect variations in flywheel speed by monitoring the sine wave signal supplied by the crankshaft position sensor.

By assessing this signal, the ECM can detect the presence of an engine misfire. At this time, the ECM will assess the amount of variation in the signal received from the crankshaft position sensor and assigns a roughness value to it. This roughness value can be viewed within the real time monitoring feature, using T4. The ECM will evaluate the signal against a number of factors and will decide whether to count the occurrence or ignore it. The ECM can assign a roughness and misfire signal for each cylinder, (i.e. identify which cylinder is misfiring).

T4 Diagnostics

The ECM stores faults as Diagnostic Trouble Codes (DTC), referred to as 'P' codes. The 'P' codes are defined by OBD legislation and, together with their associated environmental and freeze frame data, can be read using a third party scan tool or T4. T4 can also read real time data from each sensor, the adaptive values currently being employed and the current fuelling, ignition and idle settings.

P Code No Component/ Signal Fault Description
P0011 CMP/CKP/VVT Bank A CMP/CKP Position error high , VVT retard position high
P0012 CMP/CKP/VVT Bank A CMP/CKP Position error low, VVT retard position low
P0021 CMP/CKP/VVT Bank B CMP/CKP Position error, VVT retard position high
P0022 CMP/CKP/VVT Bank B CMP/CKP Position error low , VVT retard position low
P0026 VVT Bank A circuit malfunction range high/ low
P0028 VVT Bank B circuit malfunction range high/ low
P0031 UHEGO Bank A heater control circuit low
P0032 UHEGO Bank A heater control circuit high
P0051 UHEGO Bank B heater control circuit low
P0052 UHEGO Bank B heater control circuit high
P0069 HAC Sensor circuit/range performance
P0071 Ambient air temperature sensor Range performance
P0072 Ambient air temperature sensor Circuit low input
P0073 Ambient air temperature sensor Circuit high input
P0075 VVT Bank A open circuit
P0076 VVT Bank A short to ground
P0077 VVT Bank A short to battery
P0081 VVT Bank B open circuit
P0082 VVT Bank B short to ground
P0083 VVT Bank B short to battery
P0087 Fuel pressure system Low fault
P0088 Fuel pressure system High fault
P0089 Fuel pressure system Noise fault
P0093 Fuel pressure system Large leak
P0096 IAT Sensor range performance
P0101 AFM Circuit range performance
P102 AFM Circuit low input
P103 AFM Circuit high input
P0106 MAP Sensor range performance
P0107 MAP Circuit low input
P0108 MAP Circuit high input
P0111 IAT Stuck high/ low at engine start, stuck high
P0112 IAT Sensor 1 circuit low input
P0113 IAT Sensor 1 circuit high input
P0116 ECT Implausible signal
P0117 ECT Circuit low input
P0118 ECT Circuit high input
P0121 Throttle circuit 1 and 2 Range/ performance
P0122 Throttle circuit 1 Low input
P0123 Throttle circuit 1 High input
P0125 ECT Insufficient coolant temperature for closed loop control
P0128 Thermostat monitor Low coolant temperature – thermostat stuck open
P0131 UHEGO Bank A short circuit to ground
P0132 UHEGO Bank A Short circuit to battery
P0133 UHEGO Bank A slow response
P0136 HEGO Bank A adaptions
P0137 HEGO Bank A short circuit to ground
P0138 HEGO Bank A short circuit to battery
P0139 HEGO Bank A slow response
P0140 HEGO Bank A no activity
P0141 HEGO Bank A heater control circuit malfunction
P0151 UHEGO Bank B short circuit to ground
P0152 UHEGO Bank B short circuit to battery
P0153 UHEGO Bank B slow response
P0156 HEGO Bank B adaptions
P0157 HEGO Bank B short circuit to ground
P0158 HEGO Bank B short circuit to battery
P0159 HEGO Bank B slow response
P0160 HEGO Bank B no activity
P0161 HEGO Bank B heater control circuit malfunction
P00171 lambda control Bank A too lean
P0172 lambda control Bank A too rich
P0174 lambda control Bank B too lean
P0175 lambda control Bank B too rich
P0181 Fuel rail temperature sensor Temperature signal implausible
P0182 Fuel rail temperature sensor Circuit low input
P0183 Fuel rail temperature sensor Circuit high input
P0191 Fuel rail pressure sensor Range /performance
P0192 Fuel Rail Pressure Sensor Low Input
P0193 Fuel Rail Pressure Sensor High Input
P0196 Oil temperature sensor Range/performance
P0197 Oil temperature sensor Low input
P0198 Oil temperature sensor High input
P0201 Injector Circuit Malfunction - Cylinder 1
P0202 Injector Circuit Malfunction - Cylinder 2
P0203 Injector Circuit Malfunction - Cylinder 3
P0204 Injector Circuit Malfunction - Cylinder 4
P0205 Injector Circuit Malfunction - Cylinder 5
P0206 Injector Circuit Malfunction - Cylinder 6
P0207 Injector Circuit Malfunction - Cylinder 7
P0208 Injector Circuit Malfunction - Cylinder 8
P0222 APP sensor 2 Low input
P0223 APP sensor 2 High input
P0227 APP sensor 1 Low input
P0228 APP sensor 1 High input
P0229 APP sensor Intermittent fault
P0297 Active speed control Vehicle over speed condition
P0300 Misfire Random/ multiple cylinder misfire
P0301 Misfire Cylinder 1
P0302 Misfire Cylinder 2
P0303 Misfire Cylinder 3
P0304 Misfire Cylinder 4
P0305 Misfire Cylinder 5
P0306 Misfire Cylinder 6
P0307 Misfire Cylinder 7
P0308 Misfire Cylinder 8
P0313 Misfire Misfire under low fuel condition
P0316 Misfire Misfire detected in first 1000 revs
P0326 Knock sensor Sensor 1 high/low performance error
P0327 Knock sensor Bank A sensor low input fault
P0328 Knock sensor Bank A high input fault
P0331 Knock sensor Sensor 2 high/low performance error
P0332 Knock sensor Bank B sensor low input fault
P0333 Knock sensor Bank A high input fault
P0335 Crank sensor Sensor circuit malfunction during crank/ running
P0336 Crank sensor Range/performance fault
P0340 Intake CMP sensor bank A Fault during cranking/running
P0341 Intake CMP sensor bank A Range/performance fault
P0345 Intake CMP sensor bank B Fault during cranking/running
P0346 Intake CMP sensor bank B Range/performance fault
P0351 Ignition coil Circuit malfunction cylinder 1
P0352 Ignition coil Circuit malfunction cylinder 2
P0353 Ignition coil Circuit malfunction cylinder 3
P0354 Ignition coil Circuit malfunction cylinder 4
P0355 Ignition coil Circuit malfunction cylinder 5
P0356 Ignition coil Circuit malfunction cylinder 6
P0357 Ignition coil Circuit malfunction cylinder 7
P0358 Ignition coil Circuit malfunction cylinder 8
P0365 Exhaust CMP sensor bank A Fault during cranking/running
P0366 Exhaust CMP sensor bank A Range/performance fault
P0390 Exhaust CMP sensor bank B Fault during cranking/running
P0391 Exhaust CMP sensor bank B Range/performance fault
P0401 EGR system Insufficient flow detected
P0403 EGR system Valve circuit high/low input
P0405 Differential pressure sensor Short to ground
P0406 Differential pressure sensor Short to battery
P0409 Differential pressure sensor Range performance
P0420 Catalyst system bank A Efficiency below threshold
P0430 Catalyst system bank Efficiency below threshold
P0441 Purge valve Range performance
P0442 DMTL Medium leak detected
P0447 DMTL Short to ground
P0448 DMTL Short to battery
P0455 DMTL Large leak detected
P0456 DMTL Small leak detected
P0458 Purge valve Short to ground
P0459 Purge valve Short to battery
P0461 Fuel level sensor Range/performance fault
P0480 Radiator fan module Control circuit malfunction
P0493 Viscous fan Speed Out of range
P0501 Vehicle speed Range/performance malfunction
P0504 Brake switch Circuit malfunction
P0506 Idle Control System RPM Lower Than Expected
P0507 Idle Control System RPM higher Than Expected
P0512 Crank request circuit High/low input
P0513 Security key Key invalid
P0532 Air conditioning refrigerant pressure sensor Low input
P0533 Air conditioning refrigerant pressure sensor High input
P0560 Battery back up Malfunction
P0562 Sensor power supply Low input
P0563 Sensor power supply High input
P0566 Cruise control cancel switch ON fault
P0567 Cruise control resume switch ON fault
P0568 Cruise control Low/high input
P0569 Decelerate/set/inch switch ON fault
P0570 Accelerate/set/inch switch On fault
P0574 Cruise control Speed monitoring
P0576 Cruise control Low input
P0577 Cruise control High input
P0604 ECM self test RAM error
P0605 ECM self test ROM error
P0606 ECM self test Processor error
P0616 Starter relay Low input
P0617 Starter relay High input
P0627 Primary fuel pump no commands received
P0628 Fuel pump Electrical low
P0629 Fuel pump Electrical high
P0633 Security No ID in ECM
P0634 ECM temperature Internal temperature too high
P0646 Air conditioning clutch relay Low input
P0647 Air conditioning clutch relay High input
P0661 Manifold valve output drive 1 Open circuit or short circuit to ground
P0662 Manifold valve output drive 1 Short circuit to battery
P0664 Manifold valve output drive 2 Open circuit or short circuit to ground
P0665 Manifold valve output drive 2 Short circuit to battery
P0668 ECM temperature sensor Short to ground
P0669 ECM temperature sensor Short to battery
P0687 EMS control relay Relay malfunction
P0831 Clutch switch circuit A Low input
P0832 Clutch switch circuit A High input
P0834 Clutch switch circuit B Low input
P0835 Clutch switch circuit B High input
P0851 Park / Neutral Switch Input Circuit Low
P0852 Park / Neutral Switch Input Circuit High
P1136 E Box fan Fan malfunction
P1146 Generator command line Low input/ communication error
P1155 HEGO Heater bank A  
P1160 UHEGO Bank A Slow activation
P1197 UHEGO Bank A Slow activation/open shorted
P1198 UHEGO Bank B Slow activation/open shorted
P1233 Secondary fuel pump Output circuit open
P1234 Primary fuel pump No commands received
P1236 Primary fuel pump Pump not working when requested
P1244 Alternator command line High input
P1260 Security limited start Theft attempt
P1339 Secondary fuel pump Driver circuit output low/high
P1367 Ignition coil bank A  
P1368 Ignition coil bank A  
P1452 DMTL Reference current too low
P1453 DMTL Reference current too high
P1482 DMTL heater control circuit Low
P1483 DMTL heater control circuit High
P1582 Flight recorder Data stored
P1624 Security ID ID transfer process failed
P1629 Generator FR line failure
P1632 Generator Charge system failure
P1646 UHEGO sensor bank A Slow activation/ control module open shorted
P1647 UHEGO sensor bank B Slow activation/ control module open shorted
P1670 E Box fan Malfunction low
P1671 E Box fan Malfunction high
P1697 Cruise control Shorter/Longer switch ON fault
P1700 Low gear ratio plausibility check
P2066 Secondary fuel pump Range check
P2070 Manifold valve output drive 1 Performance check stuck open/closed
P2071 Manifold valve output drive 2 Performance check stuck open/closed
P2101 Electric throttle Range performance
P2103 Electric throttle Throttle duty at 100% continuously
P2105 Electric throttle MIL request duel fuel cut off
P2106 Intended reduced availability Re-configuration failure
P2118 Electric throttle system Over current detection by hardware
P2119 Electric throttle Throttle stuck open
P2122 APP sensor Circuit 2 low input
P2123 App sensor Circuit 2 high input
P2228 HAC sensor Circuit low
P2229 HAC sensor Circuit high
P2299 Accelerator pedal Brake override
P2401 DMTL Pump Ground short
P2402 DMTL Pump Battery short
P2404 DMTL Pump Noise/reference leak fault
P2450 DMTL COV stuck open
P2451 DMTL COV stuck closed
P2503 Charging system Voltage low
P2504 Charging system Voltage high
P2601 Water pump Performance fault
P2610 Engine off timer Timer malfunction
P2632 Secondary fuel pump driver circuit Output circuit open
P2633 Secondary fuel pump driver circuit Output low
P2634 Secondary fuel pump driver circuit High input
P6365 Primary fuel pump Pump not working when requested
P2636 Secondary fuel pump Low flow/ performance

CENTRAL JUNCTION BOX

The Central Junction box is used to initiate the power up and power down routines within the ECM. When the ignition is turned on, 12V is applied to the Ignition Sense input to pin 30 of connector C0635. The ECM then starts its power up routines and turns on the ECM main relay.

When the ignition is turned OFF the ECM will maintain its powered up state for several seconds (this may be up to 20 minutes in extreme cases when cooling fans are required) while it initiates its power down routine and on completion will turn off the ECM main relay.

POWER SUPPLIES

The ECM requires a permanent battery level voltage supply and a switched battery level voltage supply. The switched voltage supply is controlled by the ECM via a relay based on the condition of the Central Junction Box input (key position 2).

At key "OFF”, the ECM will maintain the switched supply active until internal self checks have been completed. The Main Supply fuse is located in the engine compartment fuse box.

PURGE VALVE

Purge Valve and Hoses



1  - Electric throttle
2  - Air intake manifold
3  - Fuel feed jump hose
4  - Purge hose connector
5  - Purge valve
6  - Purge valve bracket
7  - Hose clamp
8  - Manifold to purge valve hose

To meet increasing legislation in fuel evaporative loss the Evaporative Emissions Loss Control System has been introduced to minimise the evaporative loss of fuel vapour from the fuel system to the atmosphere. This is achieved by venting the fuel system through a vapour trap (charcoal cannister). The charcoal acts like a sponge and stores the vapour until the canister is purged under the control of the ECM.

The charcoal canister is connected with the inlet manifold, after the throttle body, via a purge valve. This valve is opened and closed according to a PWM signal from the ECM. The canister is purged by drawing clean air through the charcoal, which carries the hydrocarbons into the engine where they are burnt. To maintain drivability and emission control purging must be closely controlled as a 1% concentration of fuel vapour from the canister in the air intake may shift the air/fuel ratio by as much as 20%. Purging must be carried out at regular intervals, to regenerate the charcoal, as its storage capacity is limited, and is cycled with the Fuelling Adaption, as both cannot be active at the same time.

The ECM alters the PWM signal to the purge valve to control the rate of purging of the canister. The purging of the canister is done in a controlled manner in order to maintain the correct stichometric air/fuel mixture for the engine. It also ensures the canister itself is purged frequently enough to prevent fuel saturation of the charcoal leading to an excessive build up of fuel vapour (and hence vapour pressure) in the system which could increase the likelihood of vapour leaks.   Evaporative Emissions (303-13A Evaporative Emissions - 4.0L)