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Home >> Jaguar >> 1995 >> XJ-6 (X300) L6-4.0L (AJ16) >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Testing and Inspection >> Initial Inspection and Diagnostic Overview >> Description of On-Board Diagnostics >> Diagnostic Trouble Code Monitoring Procedures >> Fuel and Air Metering >> Adaptive Fuel

Adaptive Fuel

DIAGNOSTIC CODES:
P1171, P0170, P1172, P0172, P0174,
P0175, P1176, P1177, P1178, P1179

If the adaptive fuelling corrections exceed the limits then a fault is present and remains present until the system returns within the limits. There are limits on both the fuel and air mass flow rate corrections.

The strategy will report to the Diagnostic Status Manager (DSM) when a fuelling system fault is present and the DSM will then decide whether to store a fault code and illuminate the MIL lamp.

System Too Lean
System Too Lean - Bank 1-Reduced Flow P0174
System Too Lean - Bank 2-Reduced Flow P0171

Possible causes:
- Exhaust air leak on A, B
- Misfire on that bank
- Oxygen sensor wiring problem - partial open circuit sensor A, B
- Partially blocked injector on that bank
- Oxygen sensor low Mark Space Ratio (MSR) - Sensor fault, lean shift on A, B
- ECM fault - interface or Analogue to Digital Convertor (ADC) problem with sensor input A, B

Lean Fuelling
Lean Fuelling - Banks land 2 P1171

Possible causes:
- Run out off fuel
- Fuel pump relay fault - not driving pump
- Fuel pump failure - low pressure out of pump
- Low voltage supply to fuel pump
- Blocked fuel pipe or filter
- Fuel filter very dirty
- Pressure regulator fault - low fuel rail pressure
- Blocked injectors on both banks - dirty fuel
- Fuel pipe I rail leaks
- Wiring fault on injector supply, partial short circuit to ground
- Air flow meter low output
- Both oxygen sensors (A & B) fail to switch rich
- ECM fault - reads Battery Voltage Correction (BVC) wrongly (higher than actual)

System Too Rich
System Too Rich - Bank 1 - Excess Flow P0172
System Too Rich - Bank 2 - Excess Flow P0175

Possible causes:
- Exhaust leak on A, B
- Misfire on that bank
- Oxygen sensor wiring problem - partial short circuit to ground, sensor A, B
- Leaky injector on that bank
- Oxygen sensor high Mark Space Ratio (MSR) - Sensor fault, rich shift on A, B
- ECM fault - interface or Analogue to Digital Convertor (ADC) problem with sensor input A, B

Rich Fuelling
Rich Fuelling - Banks land 2 P1172

Possible causes:
- Pressure regulator fault - high fuel rail pressure
- Blocked fuel pipe in return to tank
- Vacuum pipe ruptured between manifold and pressure regulator
- Leaking injectors on both banks
- Airflow meter high output
- Both oxygen sensors (A and B) fail to switch lean
- ECM fault - reads Battery Voltage Correction wrongly (lower than actual)

Lean Fuelling Trim
Lean Fuelling Trim, Long Term P1176

These tests monitor the performance of the adaptive fuelling system. There are limits on both fuel mass flow rate and air mass flow rate. If the corrections it applies exceed these limits then the appropriate fault is present until the system returns within limits.

Possible causes:
- Fuel pump relay fault - not driving pump
- Low voltage supply to fuel pump
- Fuel pump failure - low pressure out of pump
- Blocked fuel pipe or fuel filter
- Fuel filter very dirty
- Pressure regulator fault - low fuel rail pressure
- Blocked injectors on both banks - dirty fuel
- Wiring fault on injector supply - partial short circuit to Ground
- Airflow meter low output
- Fuel pipe/rail leaks
- ECM fault - reads Battery Voltage Correction wrongly (higher than actual)

Rich Fuelling Trim
Rich Fuelling Trim, Long Term P1177

These tests monitor the performance of the adaptive fuelling system. There are limits on both fuel mass flow rate (FMFR) and air mass flow rate (AMFR). If the corrections it applies exceed these limits then the appropriate fault is present until the system returns within limits.

Possible causes:
- Blocked fuel pipe in return to tank
- Pressure regulator fault - high fuel rail pressure
- Vacuum pipe ruptured between manifold and pressure regulator
- Leaking injectors on both banks
- Air flow meter high output
- Injector problem - high flow or leaky injectors
- One or both oxygen sensor get a rich bias - sensor fault
- ECM fault - reads Battery Voltage Correction wrongly (lower than actual)

Lean Fuelling Trim
Lean Fuelling Trim, Long Term (AMFR) P1178

These tests monitor the performance of the adaptive fuelling system. There are limits on both fuel mass flow rate and air mass flow rate. If the corrections it applies exceed these limits then the appropriate fault is present until the system returns within limits.

Possible causes:
- Air leak in inlet manifold
- Airflow meter low output
- ECM fault - reads Battery Voltage Correction wrongly (higher than actual)

Rich Fuelling Trim
Rich Fuelling Trim, Long Term P1179

These tests monitor the performance of the adaptive fuelling system. There are limits on both fuel mass flow rate and air mass flow rate. If the corrections it applies exceed these limits then the appropriate fault is present until the system returns within limits.

Possible causes:
- Air leak in exhaust
- Air flow meter high output
- ECM fault - reads Battery Voltage Correction wrongly (lower than actual)



















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