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Jaguar XJ6 Vanden Plas 1994 – 1994 ENGINE PERFORMANCE Self Diagnostics

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Jaguar XJ6 Vanden Plas 1994 - 1994 ENGINE PERFORMANCE Self-Diagnostics


Jaguar XJ6 Vanden Plas 1994 - INTRODUCTION

If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES, proceed with self-diagnostics. If no fault codes are present after entering self-diagnostics, proceed to TESTS W/O CODES article in this section for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.).


Jaguar XJ6 Vanden Plas 1994 - SELF-DIAGNOSTIC SYSTEM DESCRIPTION MALFUNCTION INDICATOR (CHECK ENGINE) LIGHT


All models are equipped with a malfunction indicator (CHECK ENGINE) light. When CHECK ENGINE light remains on, self-diagnostic system has detected a system failure.


Jaguar XJ6 Vanden Plas 1994 - HARD FAILURES 4.0L


Hard failures cause CHECK ENGINE light to glow. Fault codes are stored in Powertrain Control Module (PCM) memory. All codes except Codes 26 and 44 will cause CHECK ENGINE light to remain illuminated (with ignition on) until fault is corrected and PCM memory is cleared.

Codes 26 and 44 and CHECK ENGINE light will remain on only until next ignition on/off cycle. Code will no longer be available to driver, but will still be stored in PCM memory.

If light comes on and remains on during vehicle operation, cause of malfunction must be determined using DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION TABLE (4.0L) . If a sensor fails, control unit will use a substitute value in its calculations to continue engine operation. In this condition, vehicle is functional but poor driveability may occur.


Jaguar XJ6 Vanden Plas 1994 - 6.0L


Hard failures cause CHECK ENGINE light to glow and the words CHECK ENGINE will be displayed on trip computer display until ignition is turned off. Fault codes are stored in Powertrain Control Module (PCM) memory. All codes will cause CHECK ENGINE light to remain illuminated (with ignition on) until fault is corrected and PCM memory is cleared.

If light comes on and remains on during vehicle operation, cause of malfunction must be determined using DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION TABLE (6.0L) . If a sensor fails, control unit will use a substitute value in its calculations to continue engine operation. In this condition, vehicle is functional but poor driveability may occur.


Jaguar XJ6 Vanden Plas 1994 - RETRIEVING CODES 4.0L


When a system fault has been detected, trouble codes can be retrieved. Vehicle must be stationary. With ignition switch in OFF position, wait 5 seconds and then turn ignition switch to position II. DO NOT start engine. Press Vehicle Condition Monitor (VCM) button, located on VCM/trip computer display panel. VCM/trip computer display panel is located below tachometer and speedometer.

Applicable trouble code will be displayed on display panel. See appropriate code in DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION TABLE (4.0L) for probable cause. When engine is started, trouble code will be deleted from written display, but CHECK ENGINE light will remain on.


Jaguar XJ6 Vanden Plas 1994 - 6.0L


When a system fault has been detected, trouble codes can be retrieved. Vehicle must be stationary. With ignition switch in OFF position, wait 5 seconds and then turn ignition switch to position II. DO NOT start engine. Trouble codes will be displayed on trip computer display. See appropriate code in DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION TABLE (6.0L) for probable cause. When engine is started, trouble code will be deleted from written display, but CHECK ENGINE light will remain on.


Jaguar XJ6 Vanden Plas 1994 - TROUBLE CODE DEFINITION



Jaguar XJ6 Vanden Plas 1994 DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION

Code Affected Circuit Probable Cause
12 Mass Airflow Sensor Not Within Range
14 Engine Coolant Temperature Sensor Open Or Short Circuit
16 Air Temperature Sensor Not In Operating Range
17 Throttle Position Sensor Open Or Short Circuit
18 TPS/Mass Airflow Sensor Signal Resistance Low At WOT
19 TPS/Mass Airflow Sensor Signal Resistance High At Idle
22 Heated O2 Sensor/Fuel Pump Relay Voltage Not Within Range
23 Fuel Control Rich Fuel Mixture
24 Ignition Amplifier Voltage Not Within Range
26 Air Leak, Running Lean Air Leak/Lean Fuel Mixture
29 Powertrain Control Module Internal Fault
33 Fuel Injector Voltage Not Within Range
34 Fuel Injector Faulty Injector Indicated
37 EGR Solenoid Valve Voltage Not Within Range
39 EGR Function Faulty System Operation
44 Heated Oxygen Sensor Fuel Mixture Rich Or Lean
46 Idle Air Control Valve (Coil 1) Voltage Not Within Range
47 Idle Air Control Valve (Coil 2) Voltage Not Within Range
48 Idle Air Control Valve Position Not Within Specification
66 Air Injection Pump Relay Incorrect Signal
68 Speed Sensor Incorrect Signal Voltage
69 (1) Park/Neutral Position Switch Engine Cranks In Drive
69 (2) Park/Neutral Position Switch Engine Cranks In Drive
89 EVAP Canister Purge Control Valve Volts Not Within Range
(1) XJ6 only.
(2) XJS only.


Jaguar XJ6 Vanden Plas 1994 DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION

Code Affected Circuit Probable Cause
13 Manifold Absolute Pressure (MAP) Sensor Not Within Range
14 Engine Coolant Temperature Sensor Open Or Short Circuit
16 Intake Air Temperature Sensor Not In Operating Range
17 Throttle Position Sensor Not In Operating Range
18 TPS/MAP Sensor Signal Resistance Low At WOT
19 TPS/MAP Sensor Signal Resistance High At Idle
23 Fuel Control Rich Fuel Mixture
34 Fuel Injector (Right Bank) Faulty Injector Indicated
36 Fuel Injector (Left Bank) Faulty Injector Indicated
44 Heated O2 Sensor (Right Bank) Fuel Mixture Rich Or Lean
45 Heated O2 Sensor (Left Bank) Fuel Mixture Rich Or Lean
49 Power Resistor Faulty Power Resistor
67 Secondary Air Injection System Faulty Secondary Air Injection System
77 RPM Signal No RPM To PCM


Jaguar XJ6 Vanden Plas 1994 - DIAGNOSTIC TROUBLE CODE FAULT DIAGNOSIS (4.0L) DTC 12: MASS AIRFLOW SENSOR


  1. Ensure engine is not misfiring. If necessary, check crankshaft position sensor, timing ring, and sensor air gap. Check voltage at mass airflow sensor pin No. 1 or 2 (zero volts) and pin No. 5 (12 volts).
  2. Check mass airflow sensor output voltage. See ADJUSTMENTS article in this section. Ensure mass airflow sensor has not been subjected to water. If necessary, dry out air intake system. Check intake duct for blockage. Repair or replace as necessary.

Jaguar XJ6 Vanden Plas 1994 - DTC 14: ENGINE COOLANT TEMPERATURE SENSOR


Information is not available from manufacturer.


Jaguar XJ6 Vanden Plas 1994 - DTC 16: INTAKE AIR TEMPERATURE SENSOR


Information is not available from manufacturer.


Jaguar XJ6 Vanden Plas 1994 - DTC 17: THROTTLE POSITION SENSOR


Information is not available from manufacturer.


Jaguar XJ6 Vanden Plas 1994 - DTC 18: THROTTLE POSITION SENSOR


Information is not available from manufacturer.


Jaguar XJ6 Vanden Plas 1994 - DTC 19: THROTTLE POSITION SENSOR/MASS AIRFLOW SENSOR CALIBRATION


Ensure Idle Air Control Valve (IACV) and overrun fuel cutoff operate with throttle closed. Check throttle position sensor. Check voltage at mass airflow sensor pin No. 1 or 2 (zero volts) and pin No. 5 (12 volts). Check mass airflow sensor output voltage. - the ADJUSTMENTS article in this section. Repair or replace as necessary.


Jaguar XJ6 Vanden Plas 1994 - DTC 22: HEATED OXYGEN SENSOR/FUEL PUMP RELAY


  1. Ensure terminal No. 85 at fuel pump/oxygen sensor heater relay is grounded while engine is cranking. If terminal is not grounded, go to next step. If terminal is grounded, go to step 3).
  2. Check that Powertrain Control Module (PCM) terminal No. 7 (Pink/Brown wire) is grounded while engine is cranking. If terminal is not grounded, replace PCM. If terminal is grounded, check for open wiring harness between PCM and fuel pump/oxygen sensor heater relay.
  3. With ignition on, check for 12 volts at terminal No. 86 of fuel pump/oxygen sensor heater relay. If voltage is not present, check for an open circuit in White/Brown wire back to main relay. If voltage is present, check or replace faulty fuel pump/oxygen sensor heater relay.

Jaguar XJ6 Vanden Plas 1994 - DTC 23: FUEL CONTROL, RUNNING RICH


  1. If EVAP canister purge control valve has an electrical signal, go to DTC 89. If no electrical signal is present, check fuel pressure at idle. Fuel pressure should be 36.3 psi (2.5 kg/cm2 ) with vacuum hose connected to fuel pressure regulator, or 43.5 (3.0 kg/cm2 ) with vacuum hose disconnected.
  2. If fuel pressure is incorrect, check fuel pressure return line for blockage. Check vacuum signal if fuel pressure is high with vacuum hose connected. If necessary, replace fuel pressure regulator.
  3. If fuel pressure is okay, check for leaking fuel injector and DTC 34. Check mass airflow sensor. Repair or replace as necessary.

Jaguar XJ6 Vanden Plas 1994 - DTC 24: IGNITION AMPLIFIER


Check continuity of ignition amplifier wiring harness. Check for faulty ignition amplifier. Repair or replace as necessary.


Jaguar XJ6 Vanden Plas 1994 - DTC 26: AIR LEAK, RUNNING LEAN


  1. Check if air pump is running when engine is hot. Air pump should work for a short period after each hot start or work for several minutes following a cold start. If air injection system is not functioning properly, check air injection system.
  2. If air injection system is functioning properly, check exhaust manifold or oxygen sensor for leakage. Check that fuel pressure is correct when engine is running under load. Repair or replace as necessary.
  3. Check for vacuum leaks to A/C system and EGR valve. Check for leaks at EGR valve transfer pipe and intake manifold. Check air induction system for leaks at elbow and hoses. Check PCV and EVAP systems for leaks, including dipstick. Repair or replace as necessary.

Jaguar XJ6 Vanden Plas 1994 - DTC 29: POWERTRAIN CONTROL MODULE


Replace faulty PCM.


Jaguar XJ6 Vanden Plas 1994 - DTC 33: LEAKING FUEL INJECTOR


Information is not available from manufacturer.


Jaguar XJ6 Vanden Plas 1994 - DTC 34: LEAKING FUEL INJECTOR


Information is not available from manufacturer.


Jaguar XJ6 Vanden Plas 1994 - DTC 37: EGR SOLENOID VALVE


  1. Ensure EGR control solenoid is properly connected. Check continuity of wiring harness between PCM and EGR control solenoid. Repair or replace as necessary.
  2. Ensure EGR control solenoid resistance is approximately 40 ohms. Apply parking brake and service brakes. Ensure PCM is grounding EGR control solenoid Green/Red wire with engine at 1200 RPM (engine at normal operating temperature). Replace PCM if it is not grounding EGR control solenoid.

Jaguar XJ6 Vanden Plas 1994 - DTC 39: EGR FUNCTION


  1. With engine at normal operating temperature and transmission in Neutral, lift EGR valve diaphragm. Engine should run rough and RPM should decrease. If engine does not run rough, check EGR transfer pipe, intake manifold, and EGR valve for blockage.
  2. If engine runs rough, apply parking brake and service brakes. With engine hot, ensure vacuum signal to EGR valve is present at 1200 RPM. If vacuum signal is not present, ensure PCM is grounding EGR control solenoid Green/Red wire or check vacuum hose routing.
  3. If vacuum signal is present, ensure EGR valve functions properly when vacuum is applied. Replace EGR valve if necessary. Ensure PCM is receiving EGR temperature sensor signal. See SENSOR RANGE CHARTS article in this section. Check continuity of wiring harness between PCM and EGR temperature sensor. Repair or replace as necessary.

Jaguar XJ6 Vanden Plas 1994 - DTC 44: HEATED OXYGEN SENSOR


  1. Ensure heated oxygen sensor is properly connected. Check continuity of wiring harness between PCM, fuel pump/oxygen sensor heater relay, and heated oxygen sensor.
  2. Ensure heated oxygen sensor is receiving 12 volts from fuel pump/oxygen sensor heater relay. Check heated oxygen sensor ground circuit. Ensure tip of heated oxygen sensor is not damaged. Repair or replace as necessary.

Jaguar XJ6 Vanden Plas 1994 - DTC 46 & 47: IDLE AIR CONTROL VALVE


Check PCM main relay power input, ignition switch power input, and PCM battery power input circuits to PCM small signal ground circuit. See PIN VOLTAGE CHARTS article in the ENGINE PERFORMANCE Section. Voltage input readings should be within 200 millivolts of each other. If necessary, repair wiring harness. Check for faulty PCM.


Jaguar XJ6 Vanden Plas 1994 - DTC 48: IDLE AIR CONTROL VALVE POSITION


Ensure idle air control valve hoses are not blocked, pinched, or restricted. Ensure idle air control valve is not stuck. Repair or replace as necessary. Reset base idle speed. See ADJUSTMENTS article in this section.


Jaguar XJ6 Vanden Plas 1994 - DTC 66: AIR INJECTION PUMP RELAY


  1. If air injection pump is operating continuously, air injection pump relay output circuit (Green/Black wire) may be grounded. Check wiring harness for short circuit to ground. If necessary, repair wiring harness or replace faulty air injection pump relay.
  2. If air injection pump does not operate continuously, ensure air pump works for a short period after each hot start or works for several minutes following a cold start. Check air injection pump relay output circuit at pump relay. See PIN VOLTAGE CHARTS article in this section. If necessary, repair wiring harness or replace faulty air injection pump relay. Check for faulty PCM.

Jaguar XJ6 Vanden Plas 1994 - DTC 68: SPEED SENSOR


Road test vehicle and check if instrument cluster indicates road speed. If road speed is not indicated, repair or replace speed sensor/instrument cluster. If road speed is indicated, check wiring harness between PCM and instrument cluster. If necessary, repair wiring harness. Check for faulty PCM.


Jaguar XJ6 Vanden Plas 1994 - DTC 69: PARK/NEUTRAL POSITION SWITCH (XJ6)


  1. With transmission In Park or Neutral, measure voltage at terminal No. 3 (Red/Blue wire) of PCM Yellow connector. Voltage should not be present. If 5 volts is present, reset gear selector switches and/or check decoder module. Clear codes and retest
  2. If 5 volts is not present, check for continuity between ground and terminal No. 3 (Red/Blue wire) of PCM Yellow connector. With transmission in Park or Neutral, continuity should exist (terminal No. 3 grounded). If continuity exists, replace PCM. If continuity does not exist, locate and repair open in Red/Blue wire.

Jaguar XJ6 Vanden Plas 1994 - DTC 69: PARK/NEUTRAL POSITION SWITCH (XJS)


Information is not available from manufacturer.


Jaguar XJ6 Vanden Plas 1994 - DTC 89: EVAP CANISTER PURGE CONTROL VALVE


Check wiring harness and connectors for intermittent fault. Check EVAP canister purge control valve function. Valve is functional if "click" can be heard or if touch can detect it is functioning properly. Check for faulty PCM.


Jaguar XJ6 Vanden Plas 1994 - DIAGNOSTIC TROUBLE CODE FAULT DIAGNOSIS (6.0L) DTC 13: MAP ABSOLUTE PRESSURE (MAP) SENSOR


  1. MAP sensor is located inside of PCM. Inspect vacuum line to MAP sensor for damaged or kinked vacuum hose. Replace as necessary. If vacuum hose is okay, disconnect MAP sensor vacuum hose at PCM. Start engine and ensure vacuum is present at MAP sensor hose. If vacuum is not present, locate and repair vacuum blockage. If vacuum is present, go to next step.
  2. Check for other diagnostic fault codes. If any other fault codes are present, repair system fault. Clear codes, road test vehicle and recheck for codes. If no other fault codes are present, go to next step.
  3. Check fuel pressure with engine under a load. Fuel pressure should be 35-45 psi (2.5-3.2 kg/cm2 ). If fuel pressure is not as specified, repair fuel delivery system as necessary. If fuel pressure is as specified, go to next step.
  4. Check fuel evaporation system electrical wiring harness connectors for proper installation. To aid in identifying fuel evaporation system component connectors, see EMISSION SYSTEMS in THEORY/OPERATION article in this section. Clean or repair connectors as necessary. If connectors are okay, go to next step.
  5. Check PCM wiring harness for opens and shorts. See PIN VOLTAGE CHARTS article in this section. Repair wiring as necessary. If wiring is okay, clear codes and recheck for Code 13. If Code 13 is still present, replace PCM.

Jaguar XJ6 Vanden Plas 1994 - DTC 14: ENGINE COOLANT TEMPERATURE (ECT) SENSOR


  1. Check ECT sensor connector for proper installation. Clean or repair connector as necessary. If connector is okay, go to next step.
  2. Check for other diagnostic fault codes. If any other fault codes are present, repair system fault and clear codes. If no other fault codes are present, go to next step.
  3. Ensure coolant level is at proper level. Top off coolant as necessary. If coolant level is okay, check thermostat operation. Replace thermostats as necessary. If thermostat operation is okay, replace ECT sensor.

Jaguar XJ6 Vanden Plas 1994 - DTC 16: INTAKE AIR TEMPERATURE (IAT) SENSOR


Ensure EAT sensor connector is connected properly. Check IAT sensor circuit at PCM wiring harness connector for opens and shorts. See PIN VOLTAGE CHARTS article in the ENGINE PERFORMANCE Section. Repair wiring as necessary. If wiring is okay, check IAT sensor resistance. See SENSOR RANGE CHARTS article in this section. Replace IAT sensor as necessary.


Jaguar XJ6 Vanden Plas 1994 - DTC 17: THROTTLE POSITION (TP) SENSOR CALIBRATION


Ensure TP sensor connector is connected properly. Check PCM wiring harness for opens and shorts. See PIN VOLTAGE CHARTS article in this section. Repair wiring as necessary. If wiring is okay, replace TP sensor.


Jaguar XJ6 Vanden Plas 1994 - DTC 18 & 19: THROTTLE POSITION (TP) SENSOR CALIBRATION


Ensure TP sensor is functioning properly. If Code 18 or 19 is present and TP sensor is functioning properly, replace TP sensor. When replacing TP sensor, manufacturer recommends using Jaguar Diagnostic System (JDS) to check TP sensor adjustment. Use JDS manufacturers instructions.


Jaguar XJ6 Vanden Plas 1994 - DTC 23, 34 & 36: FUEL CONTROL


  1. Using a stethoscope, check fuel injector operating sound during engine cranking and idling. Ensure operational sound (clicking noise) increases as engine RPM is increased. If all injectors are functioning properly, go to step 3). If any injector is not operating properly, go to next step.
  2. Check suspect injector connector for dirty or loose terminals. Repair as necessary. If connector is okay, check injector input voltage at connector. See PIN VOLTAGE CHARTS article in this section. Repair wiring as necessary.
  3. If all injectors are functioning properly in step 1), check for loose HO2S or exhaust leak. Repair as necessary. If HO2S is tight and no exhaust leaks are found, go to next step.
  4. Check fuel evaporation system electrical wiring harness connectors for proper installation. To aid in identifying fuel evaporation system component connectors, see EMISSION SYSTEMS in THEORY/OPERATION article in this section. Clean or repair connectors as necessary. If connectors are okay, go to next step.
  5. Check for other diagnostic fault codes. If any other fault codes are present, repair system fault. Clear codes, road test vehicle and recheck for codes. If no other fault codes are present, go to next step.
  6. Check PCM wiring harness for opens and shorts. See PIN VOLTAGE CHARTS article in this section. Repair wiring as necessary. If wiring is okay, check fuel pressure with engine under a load. Fuel pressure should be 35-45 psi (2.5-3.2 kg/cm2 ). If fuel pressure is not as specified, repair fuel delivery system as necessary. If fuel pressure is as specified, go to next step.
  7. Check for plugged or damaged catalytic converter(s). See MECHANICAL INSPECTION under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC TESTING article in this section. Replace converters as necessary. If converters are okay, clean or install new fuel injectors. Clear codes, road test vehicle and recheck for codes.

Jaguar XJ6 Vanden Plas 1994 - DTC 44 & 45: HEATED OXYGEN SENSOR (HO2S)


  1. Check fuel evaporation system electrical wiring harness connectors for proper installation. To aid in identifying fuel evaporation system component connectors, see EMISSION SYSTEMS in THEORY/OPERATION article in this section. Clean or repair connectors as necessary. If connectors are okay, go to next step.
  2. Ensure HO2S connector is connected properly. Check continuity of wiring harness between ECM, HO2S relay, and heated oxygen sensor. Ensure HO2S is receiving 12 volts from HO2S relay. Check heated oxygen sensor ground circuit. Ensure tip of heated oxygen sensor is not damaged. Repair or replace as necessary. If wiring and HO2S is okay, go to next step.
  3. Check for other diagnostic fault codes. If any other fault codes are present, repair system fault. Clear codes, road test vehicle and recheck for codes. If no other fault codes are present, go to next step.
  4. Check PCM wiring harness for opens and shorts. See PIN VOLTAGE CHARTS article in this section. Repair wiring as necessary. If wiring is okay, check fuel pressure with engine under a load. Fuel pressure should be 35-45 psi (2.5-3.2 kg/cm2 ). If fuel pressure is not as specified, repair fuel delivery system as necessary. If fuel pressure is as specified, go to next step.
  5. Check for plugged or damaged catalytic converter(s). See MECHANICAL INSPECTION under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC TESTING article in this section. Replace converters as necessary. If converters are okay, replace suspect HO2S.

Jaguar XJ6 Vanden Plas 1994 - DTC 49: POWER RESISTOR


Ensure power resistor connector is connected properly. Ensure all fuel injector connectors are connected properly. Check PCM wiring harness for opens and shorts. See PIN VOLTAGE CHARTS article in this section. Repair wiring as necessary. If wiring is okay, replace suspect power resistor. Clear codes, road test vehicle and recheck for codes.


Jaguar XJ6 Vanden Plas 1994 - DTC 67: SECONDARY AIR INJECTION SYSTEM (AIR)


  1. Check condition of air injection pump, belt and connecting hoses and pipes. Repair as necessary. Clear codes, road test vehicle and recheck for codes. If components are okay, go to next step.
  2. Check if air pump clutch and air injection solenoid valve operate. Clutch and solenoid should energize for about 45 seconds after a warm start. If clutch and solenoid operates as specified, go to next step. If clutch and solenoid do not operate as specified, check air injection relay, relay power circuit and ground circuits. Repair as necessary.
  3. Ensure vacuum is available to air injection solenoid valve and vacuum hose is routed properly. Repair as necessary. If vacuum is available and hose is routed properly, go to next step.
  4. Check for leaking or blocked air delivery hose between air injection pump and air rail. Repair as necessary. If delivery hose is okay, check for leaking or plugged air injection check valves. Replace check valves as necessary. If check valves are okay, go to next step.
  5. Check for restricted airways in air injection rails and cylinder heads. Clean airways as necessary. If no restrictions are found, replace air pump. Clear codes, road test vehicle and recheck for codes.

Jaguar XJ6 Vanden Plas 1994 - DTC 77: RPM SIGNAL)


NOTE: Code 77 will detect an intermittent loss of speed signal (RPM signal) from ignition system. If will not detect a missing speed signal on cranking.

  1. Ensure both Crankshaft Position (CKP) sensor connectors are connected. One CKP sensor is located at rear of engine (flywheel sensor) and other sensor is located at front of engine (TDC sensor).
  2. Turn ignition on. Battery voltage should be present at Red wire of flywheel sensor connector and at Blue wire of TDC sensor connector. If battery voltage is not present at one or both wires, locate and repair open in Red and/or Blue wire. If battery voltage is present at both wires, go to next step.
  3. Using a high output spark tester, check for spark at ignition coil wire. If spark is present, go to next step. If spark is not present, probable cause of fault is a defective flywheel sensor or TDC sensor. Replace suspect sensor as necessary.
  4. Check PCM wiring harness for opens and shorts. See PIN VOLTAGE CHART S article in this section. Repair wiring as necessary. If wiring is okay, replace PCM. Clear codes, road test vehicle and recheck for codes.

Jaguar XJ6 Vanden Plas 1994 - CLEARING CODES


Turn ignition switch to OFF position. Remove negative battery cable for at least 30 seconds to clear PCM trouble code memory.


Jaguar XJ6 Vanden Plas 1994 - PCM LOCATION 4.0L


PCM is located under dash on passenger side of vehicle, behind lower dash panel.


Jaguar XJ6 Vanden Plas 1994 - 6.0L


Electronic Fuel Injection (EFI) PCM is located inside right side of trunk, behind trim panel.


Jaguar XJ6 Vanden Plas 1994 - SUMMARY


If no hard fault codes are present, go to TESTS W/O CODES article in this section for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.