Engine Controls - System & Component Testing - 4.0l & 4.6l Land Rover Range Rover II

INTRODUCTION

Before testing separate components or systems, perform BASIC DIAGNOSTIC PROCEDURES article. Since many computer-controlled and monitored components will cause a Diagnostic Trouble Code (DTC) to set if they malfunction, also perform SELF-DIAGNOSTICS in SELF-DIAGNOSTICS - 4.0L & 4.6L article.

Note. Testing individual components does not isolate short or open circuits. Perform all resistance and voltage tests using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate shorted or open wiring harness.

ENGINE CONTROL MODULE (ECM)

Note. ECM is located in right front corner of engine compartment. (Scheme 1)

Scheme 1

1. Using a backprobe set, check for continuity in Black wires between ground connection and ECM Black 18-pin connector terminals No. 5, 9 and 10, individually. (Scheme 2) See «WIRING DIAGRAMS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__wiring-diagrams). If continuity exists, go to next step. If continuity does not exist, repair open in suspect Black wire. (Scheme 1): Locating ECM
2. Start engine and allow to idle. Using a backprobe set, measure voltage between ground and ECM Black 18-pin connector terminals No. 5, 9 and 10. Voltage should be less than one volt. If voltage is greater than one volt, check for an open, corrosion or loose ground connection. See «WIRING DIAGRAMS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__wiring-diagrams).

Power Circuits

1. Turn ignition on. Using a backprobe set, measure voltage between ground and ECM Black 18-pin connector terminal No. 8 (White wire). See «WIRING DIAGRAMS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__wiring-diagrams) .
2. If battery voltage does not exist, check fuse No. 26 (20-amp), located in engine compartment fuse box. If fuse is okay, check for an open in White wire between ECM and fuse box. If fuse is not okay, repair short in White wire between ECM and fuse box and replace fuse. See «WIRING DIAGRAMS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__wiring-diagrams) .

Scheme 2

CAMSHAFT POSITION (CMP) SENSOR & CRANKSHAFT POSITION (CKP) SENSOR SYNCHRONIZATION

1. CKP sensor is located on the left side of flywheel housing. CMP sensor is located on left front of engine.
2. Compare CKP sensor wave pattern with known-good pattern. Check wave pattern for bent teeth on reluctor ring and regularity. See DTCS P0300-P0308: MISFIRE DETECTED IN ONE OR MORE CYLINDERS testing in «SELF-DIAGNOSTICS - 4.0L & 4.6L»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-self-diagnostics-40l-46l) article. If wave pattern is okay, go to next step. If CKP wave pattern is okay and engine misfire DTCs are set, see DTC P0300-P0308: MISFIRE DETECTED IN ONE OR MORE CYLINDERS testing in «SELF-DIAGNOSTICS - 4.0L & 4.6L»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-self-diagnostics-40l-46l) article. If wave pattern is not okay, go to «CRANKSHAFT POSITION (CKP) SENSOR»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__crankshaft-position-ckp-sensor) .
3. Compare CMP sensor wave pattern with known-good wave pattern. See DTC P0340: CAMSHAFT POSITION (CMP) SENSOR MALFUNCTION in «SELF-DIAGNOSTICS - 4.0L & 4.6L»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-self-diagnostics-40l-46l) article. If wave pattern is okay, go to next step. If wave pattern is not okay, go to «CAMSHAFT POSITION (CMP) SENSOR»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__camshaft-position-cmp-sensor) .
4. Compare synchronization of CKP sensor and CMP sensor wave patterns with known-good patterns. See DTC P0340: CAMSHAFT POSITION (CMP) SENSOR MALFUNCTION in «SELF-DIAGNOSTICS - 4.0L & 4.6L»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-self-diagnostics-40l-46l) article. If wave patterns are synchronized, both sensors are okay. If wave patterns are not synchronized, go to «CAMSHAFT POSITION (CMP) SENSOR»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__camshaft-position-cmp-sensor) .

CAMSHAFT POSITION (CMP) SENSOR

1. Check for CMP sensor output wave pattern. If there is no sensor output wave pattern, go to step 4). If there is an output wave pattern, go to next step.
2. Compare wave pattern with known-good wave pattern. See DTC P0340: CAMSHAFT POSITION (CMP) SENSOR MALFUNCTION in «SELF-DIAGNOSTICS - 4.0L & 4.6L»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-self-diagnostics-40l-46l) article. If wave pattern is okay, go to next step. If wave pattern is not okay, ensure correct cam reluctor ring and cam shaft are installed in engine. It is possible for an incorrect camshaft to be installed in engine. If camshaft and reluctor ring are correct, ensure CMP sensor is correctly installed. Repair as necessary and recheck wave pattern.
3. Compare synchronization of CKP sensor and CMP sensor wave patterns with known-good patterns. See DTC P0340: CAMSHAFT POSITION (CMP) SENSOR MALFUNCTION in «SELF-DIAGNOSTICS - 4.0L & 4.6L»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-self-diagnostics-40l-46l) article. If wave patterns are synchronized, both sensors are okay. If wave patterns are not synchronized, cam timing is incorrect. Repair as necessary and recheck wave pattern.
4. Remove CMP sensor. Without touching engine block, wave CMP sensor close enough to generate an output signal. If there is still no output signal from sensor, go to next step. If there is an output wave pattern, repeat step 2). If step 2) has been repeated one time already, substitute a known-good ECM and recheck system. If symptom or indication goes away, replace original ECM.
5. Check for poor connections or loose wires between CMP sensor and ECM. See «WIRING DIAGRAMS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__wiring-diagrams) . Repair as necessary and recheck. If no problems are found with wires or connectors, replace CMP sensor and recheck. Ensure wave pattern is okay.

CRANKSHAFT POSITION (CKP) SENSOR

1. Check CKP sensor installation. Ensure sensor is secure, and that the heat shield and connector are correctly installed. If incorrect spacer is installed sensor will have either a weak signal or hit the reluctor ring. Remove CKP sensor and ensure tip is not bent or damaged. Repair or replace components as necessary.
2. Remove "D" plate from transmission bell housing and inspect condition of reluctor ring. Rotate engine and check runout of reluctor ring. If any teeth are bent or reluctor ring does not run true, replace reluctor ring and flywheel. After replacing reluctor ring check CKP sensor wave pattern. See DTC P0335 & P0336: CRANKSHAFT POSITION (CKP) SENSOR MALFUNCTION testing in «SELF-DIAGNOSTICS - 4.0L & 4.6L»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-self-diagnostics-40l-46l) article. If wave pattern is okay, repair is complete. If wave pattern is not okay, go to next step.
3. Check for poor connections or loose wires between CKP sensor and ECM. See «WIRING DIAGRAMS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__wiring-diagrams) . Repair as necessary and recheck wave pattern. If wave pattern is okay, repair is complete. If wave pattern is not okay, go to next step.
4. Measure CKP sensor resistance between sensor terminals. Nominal sensor resistance is 1235-1365 ohms. If sensor resistance is not 1000-1600 ohms, replace CKP sensor and recheck CKP sensor wave pattern.

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

Turn ignition off. Disconnect ECT sensor connectoron left side of engine. Drain small amount of coolant. Remove ECT sensor from vehicle and measure resistance at various temperatures. Replace ECT sensor if not within specification. See ENGINE COOLANT TEMPERATURE SENSOR RESISTANCE .

ENGINE COOLANT TEMPERATURE SENSOR RESISTANCE

ENGINE FUEL TEMPERATURE (EFT) SENSOR

EFT sensor is located on left side of engine, mounted to fuel rail. Turn ignition off and disconnect sensor connector. Remove EFT sensor from vehicle and measure resistance at various temperatures. Replace sensor if not within specification. See ENGINE FUEL TEMPERATURE SENSOR RESISTANCE .

ENGINE FUEL TEMPERATURE SENSOR RESISTANCE

HEATED OXYGEN SENSOR (HO2S)

1. There are 2 Primary Heated Oxygen Sensors (HO2S-1) located in front of each catalytic convertor. There are 2 Secondary Heated Oxygen Sensors (HO2S-2) located after each catalytic convertor. Start engine and bring to normal operating temperature.
2. Compare wave patterns with known-good wave patterns. See DTCS P0130-P0133, PO136-P0139, P0150-P0153, P0156-P159, P0171-P0172, P0174-P0175, P1137-P1139, P1157-P1159, P1171-P1172 & P1185-P1196: HO2S CIRCUIT MALFUNCTION testing in «SELF-DIAGNOSTICS - 4.0L & 4.6L»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-self-diagnostics-40l-46l) article.
3. Refer to «HEATED OXYGEN SENSOR VOLTAGE»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l) or «HEATED OXYGEN SENSOR HEATER RESISTANCE»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l) for correct values.

HEATED OXYGEN SENSOR VOLTAGE

HEATED OXYGEN SENSOR HEATER RESISTANCE

INTAKE AIR TEMPERATURE (IAT) SENSOR

Intake air temperature sensor is located on air cleaner housing. Turn ignition off and disconnect sensor connector. Remove sensor from vehicle and measure resistance at various temperatures. Replace sensor if not within specification. Refer to the INTAKE AIR TEMPERATURE SENSOR RESISTANCE .

INTAKE AIR TEMPERATURE SENSOR RESISTANCE

KNOCK SENSOR (KS)

There are 2 knock sensors located on either side of engine block. One mounted between cylinders No. 3 and 5, the other mounted between cylinders No. 2 and 4. Check for continuity between KS terminal and KS body. If continuity exists, replace KS.

MASS AIRFLOW SENSOR (MAF)

1. In heavily polluted atmospheres MAF sensor may become contaminated causing incorrect voltage outputs. An air intake system that is restricted, has air leaks or missing components will cause incorrect voltage outputs. Turn ignition on. Measure voltage between ground and MAF sensor 3-pin connector terminal No. 1 (Brown/Orange wire). See «WIRING DIAGRAMS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__wiring-diagrams) . If battery voltage does not exist, go to next step. If battery voltage exists, go to step 3 .
2. Measure voltage between ground and ECM Black 18-pin connector terminal No. 7 (Brown/Orange wire). If battery voltage does not exist, repair open or short in Brown/Orange wire between ECM and relay. See «WIRING DIAGRAMS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__wiring-diagrams) . If battery voltage exists, repair open in Brown/Orange wire between MAF sensor and relay. See «WIRING DIAGRAMS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__wiring-diagrams) .
3. Start engine and allow to idle. Backprobe MAF sensor 3-pin connector. Measure output voltage between sensor output terminal No. 2 (Blue/Green wire) and sensor ground terminal No. 3 (Red/Black wire). See «WIRING DIAGRAMS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__wiring-diagrams) . Voltage output should increase as air flow increases. See «MASS AIRFLOW SENSOR OUTPUT VOLTAGE»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l) .

MASS AIRFLOW SENSOR OUTPUT VOLTAGE

Scheme 3

PARK/NEUTRAL SWITCH

Note. ECM is located in right front corner of engine compartment. (Scheme 1)

Turn ignition on. Using a backprobe set, measure voltage at ECM Red 36-pin connector terminal No. 18 (Black/Orange wire). With shift lever in Park or Neutral voltage should be zero. With shift lever in Drive 12 volts should exist.

THROTTLE POSITION (TP) SENSOR

Note. On models equipped with Advanced EVAP systems, TP sensor and fuel tank pressure sensor share a 5.0 volt reference voltage. A fuel tank pressure sensor failure that causes a short circuit will affect TP sensor output and set a TP sensor DTC.

Check TP sensor output voltage. See THROTTLE POSITION SENSOR SIGNAL VOLTAGE . TP sensor output voltage should change smoothly as throttle position changes. Turn ignition off and disconnect TP sensor 3-pin connector. TP sensor resistance measured between terminals No. 1 and No. 3 should be 3200-4800 ohms. Replace TP sensor if output voltage or resistance is not as specified.

THROTTLE POSITION SENSOR SIGNAL VOLTAGE

Vehicle Speed Sensor

See DTC P0500: VEHICLE SPEED SENSOR (VSS) SIGNAL OUT OF RANGE in SELF-DIAGNOSTICS - 4.0L & 4.6L article.

Main Relay

1. Main relay may also be called the engine main control relay. Main relay is in the engine compartment fuse box which is located at the right side of the engine compartment.
2. Check for battery voltage at component side of fuse No. 37 (20-amp). See «WIRING DIAGRAMS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__wiring-diagrams). If battery voltage exists, go to next step. If battery voltage does not exist, check fuse. If fuse is not okay, repair short in circuit between fuse No. 37 and ECM Black 18-pin connector terminal No. 17 (Blue/Red wire). See «WIRING DIAGRAMS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__wiring-diagrams). If fuse is okay, repair open in power supply circuit between fuse No. 37 and battery. See appropriate POWER DISTRIBUTION wiring diagram in SYSTEM WIRING DIAGRAMS article in the WIRING DIAGRAMS section.
3. Disconnect negative battery cable. Disconnect all 3 ECM connectors. Check for continuity between component side of fuse No. 37 and ECM Black 18-pin connector terminal No. 17 (Blue/Red wire). (Scheme 2) See «WIRING DIAGRAMS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__wiring-diagrams). If continuity exists, go to step 5. If continuity does not exist, go to next step.
4. Check for continuity between component side of fuse No. 37 (20-amp) and engine compartment fuse box Pink 8-pin connector terminal No. 2 (Blue/Red wire). See «WIRING DIAGRAMS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__wiring-diagrams). If continuity exists, go to next step. If continuity does not exist, remove engine main control relay and check main relay coil continuity. If continuity exists, repair open in shorting link No. 6 located in engine compartment fuse box. If continuity does not exist, replace engine main control relay and recheck.
5. Reconnect negative battery cable. Using a fused jumper wire and backprobe set, connect battery ground to ECM Black 18-pin connector terminal No. 17 (Blue/Red wire). (Scheme 2) See «WIRING DIAGRAMS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__wiring-diagrams). Using a backprobe set, measure voltage at ECM Black 18-pin connector terminal No. 7 (Brown/Orange wire). If battery voltage does not exist, go to next step. If battery voltage exists, engine control relay is operating properly at this time. Substitute a known-good ECM and recheck for original symptom or indication. If symptom or indication goes away, replace original ECM.
6. Measure voltage at engine compartment fuse box Pink 8-pin connector terminal No. 3 (Brown/Orange wire). See «WIRING DIAGRAMS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__wiring-diagrams). If battery voltage exists, repair open in Brown/Orange wire between engine compartment fuse box and ECM Black 18-pin connector terminal No. 7. If battery voltage does not exist, check fuse No. 37 (20-amp).
7. If fuse is okay, replace engine control main relay and recheck for original symptom or indication. If fuse is not okay, check for a short in Brown/Orange wire between fuse box and all attached components. See «WIRING DIAGRAMS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__wiring-diagrams). Repair as necessary.

Fuel Pump Relay

1. Fuel pump relay is in engine compartment fuse box, which is located on right side of engine compartment. Before checking fuel pump relay, check inertia fuel shut-off switch located on engine compartment firewall. Check for continuity between inertia fuel shut-off switch terminals No. 1 (White/Orange wire) and No. 3 (White/Blue wire). If continuity exists, go to next step. If continuity does not exist, depress inertia fuel shut-off switch plunger to reset switch. If continuity still does exist, replace inertia fuel shut-off switch.
2. Turn ignition on. Measure voltage between ground and fuel pump relay terminal No. 1, located in engine compartment fuse box. See «WIRING DIAGRAMS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__wiring-diagrams). If battery voltage exists, go to next step. If battery voltage does not exist, repair power supply circuit between fuse box and battery. See appropriate POWER DISTRIBUTION wiring diagram in the SYSTEM WIRING DIAGRAMS article in the WIRING DIAGRAMS section.
3. Turn ignition off. Measure voltage between ground and fuel pump relay terminal No. 3. If battery voltage exists, go to next step. If battery voltage does not exist, check fuse No. 39 (10-amp). If necessary, replace fuse, and repair power supply circuit between fuse box and battery. See appropriate POWER DISTRIBUTION wiring diagram in SYSTEM WIRING DIAGRAMS article in the WIRING DIAGRAMS section.
4. Turn ignition off. Disconnect all 3 ECM connectors. Check for continuity in Blue/Purple wire between ECM Black 36-pin connector terminal No. 24 and engine compartment fuse box Pink 8-pin connector terminal No. 4. (Scheme 3) See «WIRING DIAGRAMS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__wiring-diagrams). If continuity exists, go to next step. If continuity does not exist, repair open in Blue/Purple wire.
5. Using a fused jumper wire and backprobe set, connect the ECM Black 36-pin connector terminal No. 24 (Blue/Purple wire) to ground. (Scheme 3) See «WIRING DIAGRAMS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__wiring-diagrams). Turn ignition on. Check fuel pump operation. If fuel pump is not operating, go to next step. If fuel pump is operating, substitute a known-good ECM and recheck for original symptom or indication. If symptom or indication goes away, replace original ECM.
6. Measure voltage between ground and engine compartment fuse box Gray 8-pin connector terminal No. 1 (White/Orange wire). If battery voltage exists, repair open in circuit between engine compartment fuse box, inertia fuel shut-off switch and fuel pump. If battery voltage does not exist, recheck fuse No. 39 (10-amp). If fuse is okay, replace fuel pump relay. If fuse is not okay, repair short in circuit between engine compartment fuse box, inertia fuel shut-off switch and fuel pump.

FUEL DELIVERY

Note. Regulated fuel pressure should be 35-37 psi (2.4-2.6 kg/cm 2 ) with engine at idle. Pressure will vary depending on amount of intake manifold vacuum acting on fuel pressure regulator.

Relieving Fuel Pressure

Fuel pressure can be released at either the fuel supply line at the fuel rail or at the fuel filter. Position shop towel around fitting to protect against fuel spray. Carefully loosen fitting. When fuel pressure has been released, tighten fitting.

Fuel Pressure Check

1. Ensure engine temperature is less than normal operating temperature. If engine is at normal operating temperature, there may be abnormal pressure readings because of hot-soak fuel vaporization. Removing fuel filler cap may reduce effect of fuel vaporization. Turn ignition off. Relieve fuel pressure. See «RELIEVING FUEL PRESSURE»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__relieving-fuel-pressure) under FUEL DELIVERY. Install fuel pressure gauge to fuel rail. Install shut-off valves in fuel supply and return lines. Activate fuel pump and bleed air from fuel pressure gauge.
2. Allow fuel pressure to stabilize and record fuel pressure. Fuel system pressure should be 35-38 psi (2.4-2.6 kg/cm 2 ) at idle. Turn fuel pump off and monitor gauge for changes in fuel pressure. If fuel pressure does not change, go to «FUEL INJECTOR BALANCE CHECK»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__fuel-injector-balance-check) . If fuel pressure decreases, close shut-off valve on fuel supply line and check fuel pressure. If fuel pressure decreases, go to next step. If fuel pressure does not decrease, check valve in fuel pump is faulty. Replace fuel pump.
3. If fuel pressure continues to decrease, close shut-off valve on fuel return line and check fuel pressure. If fuel pressure does not decrease, replace fuel pressure regulator. If fuel pressure continues to decrease, check fuel system for a leak. Repair as necessary. If no leaks are found, one or more fuel injectors may be leaking. Go to «FUEL INJECTOR BALANCE CHECK»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__fuel-injector-balance-check) .

For testing, see Fuel Pump Relay under MODULES, MOTORS, RELAYS & SOLENOIDS.

FUEL CONTROL

Fuel Injector Balance Check

1. Ensure engine temperature is less than normal operating temperature. If engine is at normal operating temperature, there may be abnormal pressure readings because of hot-soak fuel vaporization. Removing fuel filler cap may reduce effect of fuel vaporization. Turn ignition off. Relieve fuel pressure. See «RELIEVING FUEL PRESSURE»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__relieving-fuel-pressure) under FUEL DELIVERY. Install fuel pressure gauge to fuel rail.
2. Connect fuel injector tester to No. 1 injector. Connect tester Red lead to battery positive terminal and Black lead to battery negative terminal. Activate fuel pump and bleed air from fuel pressure gauge. Turn fuel pump off and allow fuel pressure to stabilize. Record stabilized fuel pressure. Set fuel injector tester for a 500 mS pulse.
3. Using fuel injector tester, trigger fuel injector No. 1 and record stabilized fuel pressure. Move tester to fuel injector No. 2. Turn fuel pump on and allow fuel pressure to stabilize. Record stabilized fuel pressure. Trigger fuel injector No. 2 and record stabilized fuel pressure. Repeat procedure for remaining fuel injectors, recording fuel pressures before and after triggering each fuel injector. Ensure fuel system is pressurized before triggering each fuel injector.
4. Compare injector pressure drop for all injectors to the average pressure drop. Injector pressure drop is the difference between recorded pressures before and after fuel injector is triggered. For example, if the pressure before the injector is triggered is 30 psi and after is 16 psi, the injector pressure drop will be 14 psi. Add pressure drop values for all 8 injectors and divide by 8 to obtain the average fuel injector pressure drop.
5. The pressure drop for each injector should be within 2 psi (more or less than) of the average injector pressure drop. For example, if the average fuel pressure drop is 14 psi, then the injector pressure drop for each injector could be 12-16 psi.
6. Closely monitor injector pressure drop on each cylinder that has a misfire. If an injector is clogged or restricted, the injector pressure drop will be more than 2 psi greater (i.e., more than 16 psi) than the average. If the injector is allowing to much fuel or is leaking, the injector pressure drop will be more than 2 psi less (i.e., less than 12 psi) than the average. Replace any injector with a fuel pressure drop more than 2 psi greater or less than the average pressure drop. If pressure drop for all injectors are within 2 psi of the average go to «FUEL INJECTOR ELECTRICAL CHECK»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__fuel-injector-electrical-check) .

Fuel Injector Electrical Check

1. Using a backprobe set, connect Snap-On Personal Automotive Computer (PAC) tester to suspect fuel injector driver terminal. See «IDENTIFYING FUEL INJECTOR DRIVER CONNECTOR TERMINALS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l). Set Snap-On PAC tester to 100 volt scale and 5.0 mS. Start engine and allow it to idle. Compare fuel injector wave pattern with known-good wave pattern. (Scheme 4)
2. If injector coil release spikes average approximately 80 volts, go to next step. An injector coil with a short will have average coil release spikes lower than 80 volts. Replace faulty fuel injector if coil release spikes average less than 80 volts.
3. Reset Snap-On PAC tester to 50 volt scale. Start engine and allow to idle. Check "On" time voltage for each injector. If "On" time voltage is constant at one volt or less, fuel injector drivers are operating properly. If "On" time voltage is not constant at one volt or less, go to next step.
4. If "On" time voltage is more than one volt, injector driver is not providing a consistent ground for the injector coil. Check for poor connections or loose wires between suspect fuel injector and ECM. See «WIRING DIAGRAMS»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__wiring-diagrams). Perform repairs as necessary. If no problems are found, substitute a known-good ECM and recheck for original symptom or indication. If symptom or indication goes away, replace original ECM.

IDENTIFYING FUEL INJECTOR DRIVER CONNECTOR TERMINALS

Scheme 4

Idle Speed Control (ISC) Stepper Motor

Turn ignition off. Disconnect IAC valve 4-pin connector. Measure resistance of IAC valve motor coils between terminals "A" and "D", and between "B" and "C". See WIRING DIAGRAMS . If resistance either coil is not 51-55 ohms, replace IAC valve and ensure warm idle position is 20-30 steps.

IGNITION SYSTEM

Note. For basic ignition checks, see 1995-98 BASIC DIAGNOSTIC PROCEDURES -- RANGE ROVER article.

TIMING CONTROL SYSTEMS

Note. Ignition timing is controlled by Land Rover's Generic Engine Management System (GEMS) and is not adjustable.

IDENTIFYING EVAP SYSTEMS

On 1997 and 1998 Range Rover 2 different EVAP systems are used. Refer to underhood emission label for identification of Advanced or Pre-Advanced EVAP system. See .

Scheme 5

PRE-ADVANCED EVAP SYSTEM

Note. The following pressure test procedure is intended to provide a method for ensuring that the EVAP system does not leak excessively and that it will effectively control evaporative emissions.

Scheme 6

1. Ensure fuel tank contains at least 2 gallons of fuel unless there has never been fuel in the system. Ensure fuel filler cap is properly installed. Disconnect line from fuel vapor separator, at EVAP canister. (Scheme 6) Using a "T" fitting and adapter, connect nitrogen cylinder and regulator, and a water manometer (0-30" H2O or more) to end of line from fuel vapor separator, at EVAP canister.
2. Pressurize EVAP system to 26.5-27.5" of H2O, allow to stabilize, and turn off nitrogen supply. Monitor water manometer for changes in EVAP system pressure. If system pressure decreases more than 2.5" of H2O in 2.5 minutes, go to next step. EVAP system is okay if pressure decreases within specification or increases slightly.
3. Maintain EVAP system pressure at 26.5-27.5" of H2O. Using soapy water, locate EVAP system leak. (Scheme 6) Repair as necessary and repeat pressure test.

ADVANCED EVAP SYSTEM

Note. Temperature differences between vehicle and test equipment can cause misleading test results because of expansion and contraction of test gases during test. Ensure vehicle and test equipment temperatures are similar.

Scheme 7

1. Ensure fuel filler cap is properly installed. Using Land Rover TestBook (use diagnostic disc DRG0002), close EVAP canister vent solenoid. Connect EVAPS Diagnostic Station System (LRA-19-004) to vehicle according to manufacturer's instructions. Connect EVAP diagnostic station Red hose to service port. (Scheme 7)
2. Open valve on nitrogen cylinder. Turn control panel valve to PRESSURE position and pressurize EVAP system to 14.5" H2O. Turn control panel valve to OFF/HOLD position and monitor pressure gauge for 2 minutes. If pressure decrease is less than 6" H2O within 2 minutes, system is okay at this time. Go to step 4. If pressure decrease is more than 6" H2O within 2 minutes, go to next step.
3. Turn control panel valve to PRESSURE position and pressurize EVAP system to 30.0" H2O. Using an ultrasonic leak detector, check all system hoses, connections and joints for leaks. Repair as necessary and repeat EVAP system pressure test. When pressure test is completed, go to next step.
4. Insert Blue pressure release hose into pressure exhaust evacuation pipe. Turn control panel valve to PRESSURE RELEASE position. Using TestBook, open EVAP canister vent solenoid. Monitor pressure gauge until EVAP system pressure is zero inches of H2O. Turn control panel valve to OFF/HOLD position and close nitrogen cylinder valve. When repairs are completed, perform «EVAP SYSTEM PRESSURE TEST DRIVE CYCLE»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-system-component-testing-40l-46l__evap-system-pressure-test-drive-cycle).

EVAP System Pressure Test Drive Cycle

1. Turn ignition on for 30 seconds. Ensure Engine Coolant Temperature (ECT) is less than 140°F (60°C).
2. Start engine and allow to idle for 2 minutes. Perform 2 light accelerations from zero to 35 MPH using light pedal pressure and slow to a stop. Perform 2 medium accelerations from zero to 45 MPH using moderate pedal pressure and slow to a stop. Perform 2 hard accelerations from zero to 55 MPH using heavy pedal pressure.
3. When second acceleration cycle is completed, increase vehicle speed to 60 MPH and continue for 5 minutes. Reduce speed to 50 MPH and continue for 5 minutes. Reduce speed to 35 MPH, continue for 5 minutes and slow to a stop.
4. Allow engine to idle for 2 minutes. Check for DTCs using Land Rover TestBook or OBD-II scan tool. If any DTC is indicated, perform specified repairs. See DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION table in «SELF-DIAGNOSTICS - 4.0L & 4.6L»(/land-rover/range-rover/ii-1994-2002/remont/testing-diagnostics/#engine-controls-self-diagnostics-40l-46l) article. If no DTCs are indicated, repair is complete.

CANISTER PURGE SOLENOID

Measure resistance between canister purge solenoid terminals. See WIRING DIAGRAMS . Resistance should be 22-40 ohms. Replace canister purge solenoid if resistance is not as specified.

MISCELLANEOUS CONTROLS

Note. Although some of the controlled devices listed here are not technically engine performance components, they can affect driveability if they malfunction.

A/C REQUEST/GRANT SIGNALS

Note. ECM is located in right front corner of engine compartment. (Scheme 1)

When A/C switch is turned on, a 12-volt A/C request signal will be seen at ECM Red 36-pin connector terminal No. 28 (Yellow/Black wire). When ECM confirms proper system operating conditions, a 12-volt A/C grant signal will be seen at ECM Black 36-pin connector terminal No. 1 (Black/Gray wire).

CONDENSER FAN REQUEST

Note. ECM is located in right front corner of engine compartment. (Scheme 1)

When A/C activation requires engine cooling fans to be turned on a 12-volt signal is sent to ECM Red 36-pin connector terminal No. 29 (Purple/Black wire). ECM will activate condenser fan relay by providing a ground through ECM Black 36-pin connector terminal No. 3 (Green/White wire).

WIRING DIAGRAMS

See ENGINE PERFORMANCE WIRING DIAGRAMS - 4.0L & 4.6L article.

See also:
• SELF-DIAGNOSTICS - 4.0L & 4.6L
• 1995-98 BASIC DIAGNOSTIC PROCEDURES -- RANGE ROVER
• ENGINE PERFORMANCE WIRING DIAGRAMS - 4.0L & 4.6L
• WIRING DIAGRAMS
• CRANKSHAFT POSITION (CKP) SENSOR
• CAMSHAFT POSITION (CMP) SENSOR
• ENGINE COOLANT TEMPERATURE SENSOR RESISTANCE
• RELIEVING FUEL PRESSURE
• FUEL INJECTOR BALANCE CHECK
• Fuel Pump Relay
• FUEL INJECTOR ELECTRICAL CHECK
• EVAP SYSTEM PRESSURE TEST DRIVE CYCLE