Engine Controls - Self-Diagnostics - Without Codes Land Rover Range Rover L322

INTRODUCTION

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

The Range Rover Petrol Engine Management System consists of the Bosch ME7.2 Engine Control Module (ECM) controlling the BMW 4.4L V8 M62 engine.

ME7.2 is a development of the Bosch M5.2.1 Engine Management System used on the Land Rover "Thor" V8 engine, the major difference being that ME7.2 is a "drive-by-wire" Engine Management system, i.e. ME7.2 has electronic throttle control.

Another significant system difference is the extensive use of a Controller Area Network (CAN) system to provide the interface to other vehicle systems.

INPUTS & OUTPUTS

INPUTS & OUTPUTS

MODE $06 DATA

Mode $06 enables access to the most current diagnostic results and thresholds of non-continuous diagnostic routines. Each individual parameter is identified by a Component Identifier (CID). (Scheme 1)

Following a power failure or after a delete error memory (Mode $03) request all values will be set to $00. Values are stored in the battery backed RAM.

Scheme 1

OBD DRIVE CYCLE INFORMATION

The following drive cycles may be used to exercise the monitors described in this document.

DRIVE CYCLE A

1. Switch on the ignition for 30 seconds.
2. Ensure engine coolant temperature is less than 60°C (140°F).
3. Start the engine and allow to idle for 2 minutes.
4. Connect a generic scan tool and check for fault codes.

DRIVE CYCLE B

1. Switch ignition on for 30 seconds.
2. Ensure engine coolant temperature is less than 60°C (140°F).
3. Start the engine and allow to idle for 2 minutes.
4. Perform 2 light accelerations, i.e. 0 to 35 mph with light pedal pressure.
5. Perform 2 medium accelerations, i.e. 0 to 45 mph with moderate pedal pressure.
6. Perform 2 hard accelerations, i.e. 0 to 55 mph with heavy pedal pressure.
7. Allow engine to idle for 2 minutes.
8. Connect a generic scan tool and, with the engine still running, check for fault codes.

DRIVE CYCLE C

1. Switch ignition on for 30 seconds.
2. Ensure engine coolant temperature is less than 60°C (140°F).
3. Start the engine and allow to idle for 2 minutes.
4. Perform 2 light accelerations, i.e. 0 to 35 mph with light pedal pressure.
5. Perform 2 medium accelerations, i.e. 0 to 45 mph with moderate pedal pressure.
6. Perform 2 hard accelerations, i.e. 0 to 55 mph with heavy pedal pressure.
7. Cruise at 60 mph for 8 minutes.
8. Cruise at 50 mph for 3 minutes.
9. Allow engine to idle for 3 minutes.
10. Connect a generic scan tool and, with the engine still running, check for fault codes.

DRIVE CYCLE D

1. Switch ignition on for 30 seconds.
2. Ensure engine coolant temperature is less than 35°C (95°F).
3. Start the engine and allow to idle for 2 minutes.
4. Perform 2 light accelerations, i.e. 0 to 35 mph with light pedal pressure.
5. Perform 2 medium accelerations, i.e. 0 to 45 mph with moderate pedal pressure.
6. Perform 2 hard accelerations, i.e. 0 to 55 mph with heavy pedal pressure.
7. Cruise at 60 mph for 5 minutes.
8. Cruise at 50 mph for 5 minutes.
9. Cruise at 35 mph for 5 minutes.
10. Allow engine to idle for 2 minutes.
11. Connect a generic scan tool and check for diagnostic trouble codes.

DRIVE CYCLE E

1. Ensure fuel tank is at least a quarter full.
2. Carry out Drive Cycle A.
3. Switch off ignition.
4. Leave vehicle undisturbed for 20 minutes.
5. Switch on ignition.
6. Connect a generic scan tool and check for diagnostic trouble codes.

DRIVE CYCLE F

1. Switch ignition on for 30 seconds.
2. Ensure Engine Coolant Temperature is less than 60°C (140°F).
3. Start Engine.
4. Ensure vehicle is in "High Range".
5. Allow engine to idle for 2 minutes.
6. Cruise at 50 mph for 2 minutes.
7. Allow engine to idle for 2 minutes.
8. Select "Low Range".
9. Allow engine to idle for 2 minutes.
10. Perform 2 light accelerations (0 to 10 mph with light pedal pressure).
11. Perform 2 medium accelerations (0 to 20 mph with moderate pedal pressure).
12. Cruise at 30 mph for 2 minutes.
13. Select "High Range".
14. Cruise at 50 mph for 2 minutes.
15. Allow engine to idle for 2 minutes.
16. Connect a generic scan tool and check for diagnostic trouble codes.

ON BOARD MONITORING

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

CATALYST MONITORING

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Catalyst Monitoring Description

Catalyst monitoring is based on the monitoring of oxygen storage capability. The (non-linear) correlation between conversion efficiency and storage capability has been shown in various investigations.

The engine closed loop feedback control results in regular lambda (normalized air/fuel ratio) oscillations in the exhaust gas. These oscillations are damped by the oxygen storage activity of the catalyst. The amplitude of the remaining lambda oscillations downstream of the catalyst indicates the storage capability.

The monitoring function compares the signal amplitudes obtained from the downstream oxygen sensors with modeled signal amplitudes. The modeled signal amplitudes are derived from a model of a borderline catalyst. If the measured amplitudes exceed those of the model, then the catalyst is considered to be defective.

Unlike the previous catalyst monitoring function, this operates over a single range of engine speed and load.

The monitoring function can be broken down into the following sub-sections

1. Computation of the downstream oxygen sensor signal amplitudes.
2. Modeling of a borderline catalyst and the downstream oxygen sensor signal amplitudes.
3. Signal evaluation.
4. Fault processing.
5. Function enable criteria.

Catalyst Monitoring Structure

For monitoring structure flow chart (Scheme 2)

Scheme 2

Computation Of The Downstream Oxygen Sensor Signal Amplitudes

The first step is the calculation of the amplitude of the signal oscillations of the oxygen sensor downstream of the catalyst. This is accomplished by extracting the oscillating signal component, computing the absolute value and averaging over time.

Modeling Of A Borderline Catalyst & The Downstream Oxygen Sensor Signal Amplitudes

The model simulates the oxygen storage capability of a borderline catalyst. The signal of the downstream oxygen sensor is simulated in the catalyst model; this is based on real-time engine operating data (air fuel ratio and airflow rate). The amplitude of the modeled signal oscillations is then calculated.

Signal Evaluation

The signal amplitude of the downstream sensors is compared with the model over a given time. If these signal amplitudes exceed the modeled amplitudes, then the oxygen storage capability of the catalyst is less than that of a borderline catalyst.

Fault Processing

If the test result for the catalyst in the vehicle shows a lower oxygen storage capability than the model, then a fault is detected and an internal flag will be set. If the fault is detected again during the next drive cycle, then the MIL will be illuminated and a diagnostic trouble code (DTC) stored.

Since the monitored engine has a catalyst for each of two cylinder banks, two evaluations are made with differing fault thresholds, one test is for deterioration in one of the catalysts and the second is at a reduced threshold to check for deterioration in both catalysts.

Function Enable Criteria

The monitoring principle is based on the detection of relevant oscillations of the downstream oxygen sensor signal during regular lambda control. It is necessary to check the driving conditions to ensure that regular lambda control is possible, e.g. fuel cut-off not present. During these conditions and for a certain time afterwards, the computation of the amplitude values and their post-processing is suspended, so that a distortion of the monitoring information is avoided.

Block Diagram Of System Operation

For system operation block diagram (Scheme 3)

Scheme 3

Catalyst Monitoring Operation

For catalyst monitoring operation and enabling conditions (Scheme 4)

Scheme 4

Catalyst Monitoring Drive Cycle Information

Catalyst monitoring drive cycle information for each DTC

1. P0420 Drive Cycle C
2. P0430 Drive Cycle C

MISFIRE MONITORING

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Misfire Monitoring Description

The method of engine misfire detection is based on evaluating the engine speed fluctuations. In order to detect misfiring at any cylinder the torque of each cylinder is evaluated by metering the time between two ignition events, which is a measure for the mean value of the speed of this angular segment. This means, a change of the engine torque results in a change of the engine speed.

Additionally the influence of the load torque will be determined. This means the influences of different road surfaces, e.g. pavement, pot holes etc. If the mean engine speed is to be measured, influences caused by road surfaces have to be eliminated. This method consists of the following main parts

1. Data acquisition, adaptation of sensor wheel is included.
2. Calculation of engine roughness.
3. Comparison with a threshold depending on operating points.
4. Some extreme conditions, during which misfire detections should be disabled for a short time.
5. Fault processing, counting procedure of single misfire events.

Misfire Monitoring Structure

For monitoring structure flow chart (Scheme 5)

Scheme 5

Data Acquisition

The duration of the crankshaft segments is measured continuously for every combustion cycle.

Sensor Wheel Adaptation

Within a defined engine speed range and during fuel cut-off, the adaptation of the sensor wheel tolerances, instead of misfire detection, is carried out. With progressing adaptation the sensitivity of the misfire detection is increasing. The adaptation values are stored in a non-volatile memory and are taken into consideration for the calculation of the engine roughness.

Misfire Detection

The following operating steps are performed for each measured segment corrected by the sensor wheel adaptation.

Calculation Of The Engine Roughness

The engine roughness is derived from the differences of the segment durations. Different statistical methods are used to distinguish between normal changes of the segment duration and the changes due to misfiring.

Detecting Of Multiple Misfiring

If several cylinders are misfiring (e.g. alternating one combustion/one misfire event) the calculated engine roughness values may be so low, that the threshold is not exceeded during misfiring and therefore misfiring would not be detected.

Based on this fact, the periodicity of the engine roughness value is used as additional information during multiple misfiring. The engine roughness value is filtered and a new multiple filter value is created. If this filter value increases due to multiple misfiring, the roughness threshold is decreased. By applying this strategy, multiple misfiring is detected reliably.

Calculation Of The Engine Roughness Threshold Value

The engine roughness threshold value consists of the base value, which is determined by a load/speed dependent map. During warm-up an engine coolant temperature dependent correction value is added. In case of multiple misfiring the threshold is reduced by an adjustable factor. Without sufficient sensor wheel adaptation the engine roughness threshold is limited to a speed dependent minimum value.

A change of the threshold towards a smaller value is limited by a variation constant.

Determination Of Misfiring

Misfire detection is performed by comparing the engine roughness threshold value with the engine roughness value.

If a misfire event is detected in a cylinder, the misfire detection of the next cylinder in firing order is deactivated to prevent a faulty diagnosis.

Statistics, Fault Processing

Within an interval of 1000 crankshaft revolutions the detected misfiring events are added for each cylinder. If the sum of all cylinder misfire incidents exceeds a predetermined value, the fault code for emission relevant misfiring is preliminarily stored. If only one cylinder is misfiring, a cylinder selective fault code is stored. If more than one cylinder is misfiring, the fault code for multiple misfiring is also stored.

Within an interval of 200 crankshaft revolutions the detected number of misfiring events is weighted and calculated for each cylinder. The weighting factor is determined by a load/speed dependent map. If the sum of cylinder misfire incidents exceeds a predetermined value, the fault code for indicating catalyst damage relevant misfiring is stored and the MIL is illuminated at once (blinking).

If the cylinder selective count exceeds the predetermined threshold, the following measures take place

1. The oxygen sensor closed loop system is switched to open loop.
2. The cylinder selective fault code is stored. If more than one cylinder is misfiring, the fault code for multiple misfire is also stored.
3. The fuel supply to the respective cylinder is cut-off.

All misfire counters are reset after each interval.

Fault Processing For Emissions Relevant Misfire

For fault processing for emissions relevant to a misfire flow chart (Scheme 6)

Scheme 6

Misfire Monitoring Operation

For misfire monitoring operation and enabling conditions (Scheme 7)

Scheme 7

Misfire Monitoring Drive Cycle Information

Misfire monitoring drive cycle information for each DTC

1. P0300 Drive Cycle C
2. P0301 Drive Cycle C
3. P0302 Drive Cycle C
4. P0303 Drive Cycle C
5. P0304 Drive Cycle C
6. P0306 Drive Cycle C
7. P0307 Drive Cycle C
8. P0308 Drive Cycle C
9. P1300 Drive Cycle C

Note. To provide compatibility with later 2005 model year DTCs, from disc 14 of the Range Rover TestBook/T4 diagnostic software, the DTCs in the following table will be displayed with new DTC numbers and descriptions. (Scheme 8)

If a standard scan tool is used then the original codes detailed previously will be displayed. If Land Rover TestBook/T4 scan tool is used some DTC changes have been made.

Scheme 8

SECONDARY AIR INJECTION SYSTEM MONITORING

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Secondary Air Injection System Description

At cold start the secondary air injection pump and valve are switched on for their normal operating function. The secondary air delivered into the exhaust gas causes a lean mixture indicated by the output voltage of the front oxygen sensor.

Any time the oxygen sensor indicates a rich mixture (voltage > a fixed limit) within a predetermined time range and the calculation of the relative secondary air mass is < (less than) a defined threshold, the secondary air injection system appears to be faulty.

A correction procedure follows immediately after the secondary air injection system is switched off. The air fuel ratio influence is determined by the deviation of the lambda-controller.

If influence < (less than) a fixed threshold, finally a fault will be detected.

If influence > (greater than) a fixed threshold the results of the diagnosis will be rejected.

As long as a lean mixture (voltage < a fixed limit) is indicated from the front oxygen sensor within a predetermined time range and the correction of air fuel ratio influence (after secondary air injection pump shuts-off) is < (less than) a fixed threshold a fault will also be detected.

Secondary Air Injection System Monitoring Structure

For secondary air injection system monitoring structure flow chart (Scheme 9)

Scheme 9

Secondary Air Injection System Monitoring Operation

For secondary air injection system monitoring operation and enabling conditions (Scheme 10)

Scheme 10

Secondary Air Injection System Drive Cycle Information

Secondary air injection system drive cycle information for each DTC

1. P0412 Not Applicable
2. P0413 Not Applicable
3. P0414 Not Applicable
4. P0418 Not Applicable
5. P0491 Not Applicable
6. P0492 Not Applicable
7. P1413 Not Applicable
8. P1414 Not Applicable

EVAPORATIVE EMISSION SYSTEM LEAK MEASUREMENT

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Leak Measurement Description

The evaporative emission system monitoring permits the detection of leaks in the evaporative emission system with a diameter of 0.020" (0.5 mm) and or greater.

By means of a Diagnostic Module Tank Leakage (DM-TL), an electrical actuated pump located at the atmospheric connection of the evaporative emission canister, a pressure test of the evaporative emission system is performed in the following order

Scheme 11

Scheme 12

Scheme 13

1. Reference Leak Measurement During the Reference Leak Measurement, the electrical actuated pump delivers through the reference restriction. The ECM system measures the pump's electrical current consumption in this section. (Scheme 11)
2. Leak Measurement During the Leak Measurement, the electrical actuated pump delivers through the EVAP canister into the fuel tank system. The pressure in the evaporative emission system may be up to 2500 Pa depending on the fuel level in the tank. The ECM measures the pump's electrical current consumption. A comparison of the currents of the reference leak measurement and the leak measurement is a measure for the leakage in the tank. (Scheme 12)
3. Pressure Release After the test the remaining pressure in the evaporative system is bled off through the EVAP canister by switching off the pump and solenoid. (Scheme 13)

EVAP System Leak Measurement Monitoring Structure

For EVAP system monitoring structure flow charts (Scheme 14), (Scheme 15) and (Scheme 16).

Scheme 14

Scheme 15

Scheme 16

EVAP System Diagnosis Frequency & MIL illumination

Diagnosis Frequency and MIL illumination: No refueling detected; leak > 0.040" (1.0 mm). (Scheme 17)

Scheme 17

Diagnosis Frequency and MIL illumination: After refueling detected; leak > 0.020" (0.5 mm). (Scheme 18)

Scheme 18

Description Of EVAP Canister Purge System Flow Check

The purge flow from the EVAP canister through the EVAP canister purge valve is monitored after fuel system adaptation is completed and the lambda controller is at closed loop condition. The diagnosis is started during regular purging.

EVAP Canister Purge System Monitoring Structure

For EVAP system monitoring structure flow chart (Scheme 19)

Scheme 19

Step 1 - For Rich Or Lean Mixture

Flow through the EVAP canister purge valve is assumed as soon as the lambda controller is compensating for a rich or a lean shift. After this procedure the diagnosis is completed and the EVAP canister purge system resumes working normally.

Step 2 - For A Stoichiometric Mixture

In this case the lambda controller does not need to compensate for a deviation. Therefore, after finishing the regular purging, the EVAP canister purge valve is opened and closed abruptly several times.

The effect of additional cylinder charge will trigger a variation of the engine idle speed.

A predetermined value is reached if the system functions properly and the diagnosis procedure is completed.

To start the diagnosis function (step 2) several conditions have to be satisfied

1. Vehicle speed = 0.
2. Engine at idle speed.
3. Closed loop of lambda controller.
4. Engine coolant temperature > fixed limit.
5. Transfer gears in high range.

Furthermore if the diagnosis has already been started and one of the conditions has not been satisfied continuously, the process will be interrupted and started again later

1. Engine idle speed variation < fixed limit.

Fuel Evaporative Emission System Monitoring

For fuel evaporative emission system monitoring and enabling conditions (Scheme 20)and (Scheme 21).

Scheme 20

Scheme 21

EVAP System Drive Cycle Information

Drive cycle information for each DTC

1. P0440 Drive Cycle C
2. P0443 Drive Cycle C
3. P0444 Drive Cycle C
4. P0445 Drive Cycle C
5. P1450 Not Applicable
6. P1451 Not Applicable
7. P1452 Not Applicable
8. P1453 Not Applicable
9. P1455 Drive Cycle A
10. P1489 Drive Cycle A
11. P0442 See «DRIVE CYCLE FOR P0422 & P0455»(/land-rover/range-rover/l322-2002-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-without-codes__drive-cycle-for-p0422-p0455) .
12. P0455 See «DRIVE CYCLE FOR P0422 & P0455»(/land-rover/range-rover/l322-2002-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-without-codes__drive-cycle-for-p0422-p0455) .

Drive Cycle For P0422 & P0455

1. Refuel the vehicle.
2. Leave the vehicle to stand for at least 5 hours with an ambient temperature of greater than 36°F (2°C).
3. Drive the vehicle for at least 20 minutes.
4. Switch the engine off.
5. Check that the fuel level is between 15% and 85 % full.
6. Connect a generic scan tool and check for fault codes.

Note. To provide compatibility with later 2005 model year DTCs, from disc 14 of the Range Rover TestBook/T4 diagnostic software, the DTCs in the following table will be displayed with new DTC numbers and descriptions. (Scheme 22)

If a standard scan tool is used then the original codes detailed previously will be displayed.

Scheme 22

FUEL SYSTEM MONITORING

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Mixture Primary Control

The air mass taken in by the engine and the engine speed are measured. These signals are used to calculate an injection signal. This mixture primary control follows fast load and speed changes.

Lambda-Control

The ECM compares the oxygen sensor signal of the sensor upstream of the catalyst with a reference value and calculates a correction factor for the primary control.

Adaptive Primary Control

Drifts and faults in sensors and actuators of the fuel delivery system as well as unmetered air leakage into the intake system influence the primary control. This causes deviations in the air fuel ratio. The adaptive primary control determines the controller correction in two different ranges.

Ranges Of Learning Correction Coefficients tra & fra

Lambda deviations in range 1 are compensated by an additive correction value multiplied by an engine speed term. By this means an additive correction per time unit is derived. (Scheme 23)

Scheme 23

Lambda deviations in range 2 are compensated by a multiplicative factor. (Scheme 23)

Each value is determined only within its corresponding range. But each adaptive value corrects the primary control within the whole load and speed range of the engine. After the next start, the stored adaptive values are included in the calculation of the primary control; just before the closed loop fuelling control is activated.

Abbreviations For The Fuel Delivery System

1. NU1 Upper engine speed threshold, range 1.
2. QU1 Upper air flow threshold, range 1.
3. tra Additive learning correction coefficient per time unit (range 1).
4. TRADN Lower diagnosis threshold of tra.
5. TRADX Upper diagnosis threshold of tra.
6. QL2 Lower air flow threshold, range 2.
7. QU2 Upper air flow threshold, range 2.
8. RLU2 Upper engine load threshold, range 2.
9. RLL2 Lower engine load threshold, range 2.
10. fra Multiplicative learning correction coefficient (range 2).
11. FRADN Lower diagnosis threshold of fra.
12. FRADX Upper diagnosis threshold of fra.

Diagnosis Of Fuel Delivery System

Faults in the fuel delivery system can occur which cannot be compensated for by the adaptive control. In this case the adaptive values leave a predetermined range. If the adaptive value is outside this predetermined range, and if the condition is again present on a subsequent drive cycle, the MIL is illuminated and the appropriate DTC's are stored.

Fuel System Monitoring Structure

For fuel system monitoring structure and flow chart (Scheme 24)

Scheme 24

Fuel System Monitoring & Enabling Conditions

For fuel system monitoring and enabling conditions (Scheme 25)

Scheme 25

Fuel System Drive Cycle Information

Drive cycle information for each DTC

1. P0171 Drive Cycle C
2. P0172 Drive Cycle C
3. P0174 Drive Cycle C
4. P0175 Drive Cycle C
5. P1171 Drive Cycle C
6. P1172 Drive Cycle C
7. P1174 Drive Cycle C
8. P1175 Drive Cycle C

Note. To provide compatibility with later 2005 model year DTCs, from disc 14 of the Range Rover TestBook/T4 diagnostic software, the DTCs in the following table will be displayed with new DTC numbers and descriptions. (Scheme 26)

If a standard scan tool is used then the original codes detailed previously will be displayed.

Scheme 26

OXYGEN SENSOR MONITORING

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Oxygen Sensor Monitoring Description

The response rates of the up stream oxygen sensors are monitored by measuring the period of the lambda control oscillations. (Scheme 27)

Scheme 27

Oxygen Sensor Monitoring Structure

For oxygen sensor monitoring structure and flow chart (Scheme 28)

Scheme 28

Diagnosis Procedure Of The Monitor Sensor (Downstream)

The activity of the monitor sensor after reaching operating conditions is determined by two different procedures

1. Oscillation Check (Line Crossing) If the following checks are correct, the monitor sensor will be regarded as satisfactory: The monitor sensor signal (sensor voltage) is greater than or equal to the nominal value of the TV-Correction and voltage increases, if the lambda control goes to the lean side, or The monitor sensor signal (sensor voltage) is less than the nominal value of the TV-Correction and voltage decreases, if the lambda control goes to the rich side.
2. Fuel Cut Off Check Additionally to the previous checks (A and B) the signal behavior of the monitor sensor is checked in case of fuel cut off. Therefore the monitor sensor voltage has to be below a given nominal value in case of fuel cut off. If the monitor sensor is detected faulty by checks A or B, a DTC is stored and the MIL is illuminated at the next driving cycle.

Oxygen Sensor Heater Monitoring Description

For proper function of the oxygen sensor, the sensor element must be heated. A non-functioning heater delays the sensor readiness for closed loop control and influences emissions.

The monitoring function measures both, sensor heater current (voltage drop over a shunt) and the heater voltage (heater supply voltage) to calculate the sensor heater resistance.

The monitoring function is activated once per trip, if the heater has been switched on for a certain time period and the current has stabilized.

Characteristics

1. ECM controlled switching of the sensor heater.
2. One shunt for each pair of O2 sensors upstream and downstream of the catalysts for current measurement.

Oxygen Sensor Heater Monitoring Structure

For oxygen sensor heater monitoring structure and flow chart (Scheme 29)

Scheme 29

Oxygen Sensor Circuit Monitoring

Monitoring for electrical faults in the O2S's both upstream and downstream of the catalyst. (Scheme 30)and (Scheme 31).

Implausible voltages

1. Analogue to Digital Converter voltages exceeding the maximum threshold (VMAX) are caused by a short circuit to B+.
2. Analogue to Digital Converter voltages falling below the minimum threshold (VMIN) are caused by a short circuit of the sensor signal or sensor ground to the ECM ground.
3. An open circuit of the sensor can be detected if the Analogue to Digital Converter voltage remains within a specified range after the sensor has been heated for a certain time.

Scheme 30

Scheme 31

Oxygen Sensor Monitoring Drive Cycle Information

Drive cycle information for each DTC

1. P0030 Drive Cycle C
2. P0031 Drive Cycle C
3. P0032 Drive Cycle C
4. P0036 Drive Cycle C
5. P0037 Drive Cycle C
6. P0038 Drive Cycle C
7. P0050 Drive Cycle C
8. P0051 Drive Cycle C
9. P0052 Drive Cycle C
10. P0056 Drive Cycle C
11. P0057 Drive Cycle C
12. P0058 Drive Cycle C
13. P0130 Drive Cycle C
14. P0132 Drive Cycle C
15. P0133 Drive Cycle C
16. P0134 Drive Cycle C
17. P0135 Drive Cycle C
18. P0136 Drive Cycle C
19. P0138 Drive Cycle C
20. P0139 Drive Cycle C
21. P0140 Drive Cycle C
22. P0141 Drive Cycle C
23. P0150 Drive Cycle C
24. P0152 Drive Cycle C
25. P0153 Drive Cycle C
26. P0154 Drive Cycle C
27. P0155 Drive Cycle C
28. P0156 Drive Cycle C
29. P0158 Drive Cycle C
30. P0159 Drive Cycle C
31. P0160 Drive Cycle C
32. P0161 Drive Cycle C

Note. To provide compatibility with later 2005 model year DTCs, from disc 14 of the Range Rover TestBook/T4 diagnostic software, the DTCs in the following table will be displayed with new DTC numbers and descriptions. (Scheme 32)

If a standard scan tool is used then the original codes detailed above will be displayed.

Scheme 32

THERMOSTAT MONITORING

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Thermostat Monitoring Description

The diagnostic checks for a partially open thermostat, under conditions when the thermostat would be expected to be shut. (Scheme 33)

Scheme 33

A second coolant temperature sensor is installed in the outlet from the radiator. If the enablement criteria are met and the engine coolant temperature is less than the normal thermostat opening temperature, then the diagnostic will run.

The diagnostic looks at the difference between engine coolant temperature and the radiator outlet temperature. This gives the temperature drop across the radiator.

If the temperature drop is less than a threshold, and there is flow across the radiator, this points to leakage through the thermostat.

Thermostat Monitoring Structure

For thermostat monitoring structure and flow chart (Scheme 34)

Scheme 34

Thermostat Circuit Monitoring

For thermostat circuit monitoring and enabling conditions (Scheme 35)

Scheme 35

Thermostat Drive Cycle Information

Drive cycle information for each DTC

1. P0128 Drive Cycle D
2. P1117 Drive Cycle D
3. P1118 Drive Cycle D

Note. To provide compatibility with later 2005 model year DTCs, from disc 14 of the Range Rover TestBook/T4 diagnostic software, the DTCs in the following table will be displayed with new DTC numbers and descriptions. (Scheme 36)

If a standard scan tool is used then the original codes detailed above will be displayed.

Scheme 36

POSITIVE CRANKCASE VENTILATION (PCV) SYSTEM MONITORING

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

PCV System Description

Crankcase gases from the engine enter the separator (1) via the breather hose (4). Oil drains from the separator back to the sump through the drain hose (9) and pipe (14). Crankcase gases are drawn into the intake manifold through the breather hose (5) and PCV valve (17). An additional drain hose (12) runs from the lowest point of the PCV valve to the sump via the drain pipe (14). (Scheme 37)

None of the components in the breather system require servicing and the PCV valve is securely attached to the intake manifold.

All the hoses are securely fastened with clamps (8) and (9), and clips (6), (7) and (13).

Scheme 37

PCV Monitoring Strategy Description

If any of the pipes or hoses in the breather system are disconnected, then the additive per time part (tra) of the fuel system diagnostic will reach the enrichment limit on both cylinder banks. This means that fault codes P1171 and P1174 will be stored. (Scheme 38)

Scheme 38

PCV Monitoring Drive Cycle Information

PCV monitoring drive cycle information for each DTC

1. P1171 Drive Cycle C
2. P1172 Drive Cycle C
3. P1174 Drive Cycle C
4. P1175 Drive Cycle C

Note. To provide compatibility with later 2005 model year DTCs, from disc 14 of the Range Rover TestBook/T4 diagnostic software, the DTCs in the following table will be displayed with new DTC numbers and descriptions. (Scheme 39)

If a standard scan tool is used then the original codes detailed above will be displayed.

Scheme 39

CRANKSHAFT SPEED & POSITION SENSOR

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Crankshaft Speed & Position Sensor Description

The Crankshaft Speed and Position Sensor interface consists of an input signal, a reference signal (ground) and a ground screen.

There are two diagnostic checks of the Crankshaft Speed and Position Sensor, a fault is detected if

1. A signal has been received from the Camshaft Sensor but no signal has been received from the Crankshaft Speed and Position Sensor.
2. The difference between the counted number of teeth and the actual number of teeth is greater than 1. (Scheme 40)

Scheme 40

Crankshaft Speed & Position Sensor Drive Cycle Information

Crankshaft speed and position sensor monitoring drive cycle information for each DTC

1. P0335 Drive Cycle A
2. P0370 Drive Cycle A

CAMSHAFT POSITION CONTROL INTERFACE (VANOS)

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Camshaft Position Control Interface (VANOS) Description

The Camshaft Position Control Interface consists (for each bank) of 1 PWM output drive to control the inlet camshaft position, and 1 PWM input signal for camshaft position feedback. (Scheme 41)

There is one diagnostic check of the Camshaft Position Signal, a fault is detected if

1. If the signal does not change state (high to low or low to high voltage) every crankshaft revolution.

There are five diagnostic checks of the Variable Camshaft Timing, a fault is detected if

1. The enabling conditions are satisfied and the PWM output drive voltage is less than 3 volts.
2. The enabling conditions are satisfied and the PWM output drive voltage is lees than 5 volts.
3. The enabling conditions are satisfied and the PWM output drive current is greater than 2.4 amps.
4. The alignment with the crank angle is less than 160° or greater than 185°.
5. The time taken to change timing is greater than 4-10 seconds (dependent upon the Engine Coolant Temperature).

Scheme 41

Camshaft Position Control Interface Drive Cycle Information

Camshaft Position Control Interface monitoring drive cycle information for each DTC

1. P0340 Drive Cycle A
2. P0345 Drive Cycle A
3. P1523 Drive Cycle A
4. P1524 Drive Cycle A
5. P1525 Drive Cycle A
6. P1526 Drive Cycle A
7. P1527 Drive Cycle A
8. P1528 Drive Cycle A
9. P0010 Drive Cycle C
10. P0011 Drive Cycle C
11. P0012 Drive Cycle C
12. P0020 Drive Cycle C
13. P0021 Drive Cycle C
14. P0022 Drive Cycle C

Note. To provide compatibility with later 2005 model year DTCs, from disc 14 of the Range Rover TestBook/T4 diagnostic software, the DTCs in the following table will be displayed with new DTC numbers and descriptions. (Scheme 42)

If a standard scan tool is used then the original codes detailed above will be displayed.

Scheme 42

ENGINE COOLANT TEMPERATURE SENSOR

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Engine Coolant Temperature Sensor Description

The engine coolant temperature interface consists of 1 analogue voltage input signal for engine coolant temperature and a reference ground. Note that the sensor itself is a dual element sensor with one element used by the ECM and the second element used by the Instrument Pack. (Scheme 43)

There are four diagnostic checks of the Engine Coolant Temperature sensor, a fault is detected if

1. If the resistance of the sensor is less than 0.05 k/ohms.
2. If the resistance of the sensor is greater than 75.8 k/ohms.
3. The time taken to reach the closed loop fuelling enable temperature exceeds a threshold.
4. The difference between the Engine Coolant Temperature Model and the temperature indicated by the Engine Coolant Temperature sensor is greater than a threshold.

Scheme 43

Engine Coolant Temperature Drive Cycle Information

Engine coolant temperature monitoring drive cycle information for each DTC

1. P0116 Drive Cycle D
2. P0117 Drive Cycle D
3. P0118 Drive Cycle D
4. P0125 Drive Cycle D

MASS AIRFLOW SENSOR & INTAKE AIR TEMPERATURE SENSOR

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Mass Airflow Sensor Description

Note. The Mass Airflow Sensor is a combined Mass Airflow sensor and Intake Air Temperature sensor.

The Mass Airflow Interface consists of 1 analogue voltage input signal for Air Flow, a reference supply (5V) voltage and ground reference voltage. (Scheme 44)

There are four Mass Airflow sensor diagnostic checks, a fault is detected if

1. The mass airflow signal exceeds a minimum threshold.
2. The mass airflow signal exceeds a maximum threshold.
3. The actual airflow is greater than the calculated airflow derived from the throttle position.
4. The actual airflow is less than the calculated airflow derived from the throttle position.

Scheme 44

Mass Airflow Sensor Drive Cycle Information

Mass Airflow Sensor monitoring drive cycle information for each DTC

1. P0102 Drive Cycle C
2. P0103 Drive Cycle C
3. P1102 Not Applicable
4. P1103 Not Applicable

Note. To provide compatibility with later 2005 model year DTCs, from disc 14 of the Range Rover TestBook/T4 diagnostic software, the DTCs in the following table will be displayed with new DTC numbers and descriptions. (Scheme 45)

If a standard scan tool is used then the original codes detailed above will be displayed.

Scheme 45

INTAKE AIR TEMPERATURE SENSOR

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Intake Air Temperature Interface Description

The intake air temperature interface consists of 1 analogue voltage input signal for Intake Air Temperature. (Scheme 46)

There is one Intake Air Temperature Sensor diagnostic, a fault is detected if

1. The resistance of the sensor exceeds a minimum or maximum threshold.

Scheme 46

Intake Air Temperature Sensor Drive Cycle Information

Intake Air Temperature Sensor monitoring drive cycle information for each DTC

1. P0112 Drive Cycle B
2. P0113 Drive Cycle B

KNOCK SENSOR

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Knock Sensor Interface Description

The knock sensor interface consists of 4 input signal and 4 screen grounds. (Scheme 47)

There are four knock sensor diagnostic checks, a fault is detected if

1. The engine speed is greater than 2200 RPM, the ECT is greater than 40.5°C (104.9°F) input voltage exceeds a minimum voltage threshold.
2. The engine speed is greater than 2200 RPM, the ECT is greater than 40.5°C (104.9°F) and the input voltage exceeds a maximum voltage threshold.
3. The engine speed is less than 5400 RPM, the ECT is greater than 40°C (104°F) and no knock sensor signal has been received.
4. The engine speed is less than 5400 RPM, the ECT is greater than 40°C (104°F) and the knock signal has deviated from the test signal.

Scheme 47

Knock Sensor Drive Cycle Information

Knock sensor monitoring drive cycle information for each DTC

1. P0324 Drive Cycle C
2. P0327 Drive Cycle C
3. P0328 Drive Cycle C
4. P0332 Drive Cycle C
5. P0333 Drive Cycle C
6. P1327 Drive Cycle C
7. P1328 Drive Cycle C
8. P1332 Drive Cycle C
9. P1333 Drive Cycle C

FUEL TANK LEVEL SENSOR

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Fuel Tank Level Sensor Description

There are three fuel level sensor diagnostic checks. (Scheme 48) A fault is detected if

1. The fuel consumption calculated by the ECM and the change in the fuel tank level differs by 15%.
2. The fuel level signal received from the instrument pack is greater than or equal to 127%.
3. No fuel level signal has been received from the instrument pack within the last 2.5 seconds.

Scheme 48

Fuel Tank Level Sensor Drive Cycle Information

Fuel level signal monitoring drive cycle information for each DTC

1. P0461 Not Applicable
2. P0463 Not Applicable
3. P0464 Not Applicable

THROTTLE POSITION SENSOR

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Throttle Position Sensor Description

The throttle position sensor interface consists of 2 analogue signals from which Driver Demand is determined. (Scheme 49)

There are three Throttle Position Sensor diagnostic checks, a fault is detected if

1. The enabling conditions have been meet and the signal voltage from potentiometer number 1 is less than 0.25 volts or the signal voltage from potentiometer number 2 is less than 0.19 volts.
2. The enabling conditions have been meet and the signal voltage from either of the potentiometers exceeds 4.75 volts.
3. The engine speed is greater than 1320 RPM and the difference between the two potentiometer signals is greater than 6.3%.
4. The engine speed is greater than 1320 RPM, the difference between the 2 potentiometer signals is greater than 6.3% and the difference between the potentiometer signal and substitute throttle position is greater than 10.2%.

Scheme 49

Throttle Position Sensor Drive Cycle Information

Throttle position sensor monitoring drive cycle information for each DTC

1. P0120 Drive Cycle A
2. P0121 Drive Cycle A
3. P0122 Drive Cycle A
4. P0123 Drive Cycle A
5. P0221 Drive Cycle A
6. P0222 Drive Cycle A
7. P0223 Drive Cycle A

ENGINE CONTROL MODULE SELF TEST

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Engine Control Module Self Test Description

The ECM performs a number of self-test integrity diagnostics on its internal hardware and software to check for faults. An error is detected if the ECM receives no CAN messages for at least 0.5 seconds and the calculated checksums at power up/down do not match the values stored in FLASH EPROM. (Scheme 50)

Scheme 50

Engine Control Module Self Test Drive Cycle Information

Engine control module self test monitoring drive cycle information for each DTC

1. P1646 Drive Cycle A
2. P0604 Drive Cycle A
3. P0605 Drive Cycle C
4. P0606 Drive Cycle C

Note. To provide compatibility with later 2005 model year DTCs, from disc 14 of the Range Rover TestBook/T4 diagnostic software, the DTCs in the following table will be displayed with new DTC numbers and descriptions. (Scheme 51)

If a standard scan tool is used then the original codes detailed above will be displayed.

Scheme 51

AMBIENT AIR TEMPERATURE INTERFACE

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Ambient Air Temperature Interface Description

The ECM receives Ambient Temperature via CAN. The DTC is be logged by the ECM if the Instrument Pack sends a fault condition signal. (Scheme 52)

Scheme 52

Ambient Air Temperature Drive Cycle Information

Ambient Air Temperature monitoring drive cycle information for each DTC

1. P1114 Drive Cycle A

Note. To provide compatibility with later 2005 model year DTCs, from disc 14 of the Range Rover TestBook/T4 diagnostic software, the DTCs in the following table will be displayed with new DTC numbers and descriptions. (Scheme 53)

If a standard scan tool is used then the original codes detailed above will be displayed.

Scheme 53

VEHICLE SPEED INTERFACE

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Vehicle Speed Interface Description

The Vehicle Speed Interface consists of 1 digital input from the ABS Control Module. (Scheme 54)

There is one Vehicle Speed Interface diagnostic checks, a fault is detected if

1. The enabling conditions have been satisfied and the output signal from the ABS Control Module is less than 6.2 mph.

Scheme 54

Vehicle Speed Interface Monitoring Drive Cycle Information

Vehicle speed interface monitoring drive cycle information for each DTC

1. P0500 Drive Cycle C

TRANSFER BOX CONTROL MODULE INTERFACE

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Transfer Box Control Module Interface Description

The ECM communicates with the Transfer Box Control Module via CAN. The data within the CAN message is checked for robustness and CAN generated fault information. (Scheme 55)

Scheme 55

Transfer Box Control Module Interface Drive Cycle Information

Transfer box control module interface monitoring drive cycle information for each DTC

1. P1700 Drive Cycle F
2. P1709 Drive Cycle F

Note. To provide compatibility with later 2005 model year DTCs, from disc 14 of the Range Rover TestBook/T4 diagnostic software, the DTCs in the following table will be displayed with new DTC numbers and descriptions. (Scheme 56)

If a standard scan tool is used then the original codes detailed above will be displayed.

Scheme 56

CAN SYSTEM

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

CAN System Description

The ECM communicates with several vehicle system Control Modules by using the CAN high-speed data system. An error is detected if the ECM receives no CAN messages for at least 0.5 seconds from the TCM or for at least 1.0 second from the Transfer Box Control Module. (Scheme 57)

Scheme 57

CAN System Drive Cycle Information

CAN system monitoring drive cycle information for each DTC

1. P1646 Drive Cycle A
2. P1651 Drive Cycle A

Note. To provide compatibility with later 2005 model year DTCs, from disc 14 of the Range Rover TestBook/T4 diagnostic software, the DTCs in the following table will be displayed with new DTC numbers and descriptions. (Scheme 58)

If a standard scan tool is used then the original codes detailed above will be displayed.

Scheme 58

FUEL INJECTORS

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Fuel Injectors Description

Each fuel injector (total of 8) is driven directly by the ECM.

The ECM monitors the output power stages of the injector drivers for electrical faults. (Scheme 59) A fault is detected if any of the following conditions is satisfied

1. Fuel injector driver short circuit to B+, i.e. the driver current is greater than 2.4 Amps.
2. Fuel injector driver short circuit to GND, i.e. the driver voltage is less than 3 volts.
3. Fuel injector driver open circuit, i.e. the driver voltage is less than 5 V.

Scheme 59

Fuel Injectors Monitoring Drive Cycle information

Fuel injectors monitoring drive cycle information for each DTC

1. P0201 to P0208 Drive Cycle A
2. P0261 Drive Cycle A
3. P0262 Drive Cycle A
4. P0264 Drive Cycle A
5. P0265 Drive Cycle A
6. P0267 Drive Cycle A
7. P0268 Drive Cycle A
8. P0270 Drive Cycle A
9. P0271 Drive Cycle A
10. P0273 Drive Cycle A
11. P0274 Drive Cycle A
12. P0276 Drive Cycle A
13. P0277 Drive Cycle A
14. P0279 Drive Cycle A
15. P0280 Drive Cycle A
16. P0282 Drive Cycle A
17. P0283 Drive Cycle A

IDLE SPEED CONTROL ACTUATOR

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Idle Speed Control Actuator Description

The ECM controls the engine idle speed based on various engine/vehicle operating conditions. (Scheme 60)

There is one Idle Speed Control Actuator functional check, a fault is detected if

1. The enabling conditions are satisfied and the actual engine speed differs from the desired engine speed by more than 100 RPM.

Idle Speed Control Actuator Drive Cycle Information

Fuel injectors monitoring drive cycle information for each DTC

1. P0506 Drive Cycle C
2. P0507 Drive Cycle C

ELECTRONIC THROTTLE INTERFACE

Note. For specific Diagnostic Trouble Code (DTC) testing, see DIAGNOSTIC TESTS article.

Electronic Throttle Interface Description

The Electronic Throttle Interface consists of 2 PWM output drives to control the throttle blade position, with 2 analogue signals for throttle position feedback. The 2 position signals have inverted characteristics. (Scheme 61)

There are three Electronic Throttle diagnostic checks, a fault is detected if

1. The battery voltage is greater than 7 volts and the difference between the actual and target throttle position is greater than 4%.
2. Throttle Control Unable to learn the lower mechanical stop position.
3. Throttle Control Return spring problem.

Scheme 60

Electronic Throttle Interface Drive Cycle Information

Electronic throttle interface monitoring drive cycle information for each DTC

1. P1630 Drive Cycle C
2. P1638 Drive Cycle A
3. P1639 Drive Cycle A

Note. To provide compatibility with later 2005 model year DTCs, from disc 14 of the Range Rover TestBook/T4 diagnostic software, the DTCs in the following table will be displayed with new DTC numbers and descriptions. see scheme 62

If a standard scan tool is used then the original codes detailed above will be displayed.

Scheme 61

See also:
• DIAGNOSTIC TESTS
• DRIVE CYCLE FOR P0422 & P0455