Audi Cars 1999-05

1.8L L4 - Std 7

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Trouble Code: P1676



Drive by Wire-MIL Circuit Electrical Malfunction

Possible Causes:



Circuit from the MIL to the ECM
 
ECM has failed
 
Circuit from the EPC to the ECM
 

Trouble Code: P1677



Drive by Wire-MIL Circuit Short to B+

Possible Causes:



Circuit from the MIL to the ECM
 
ECM has failed
 
Circuit from the EPC to the ECM
 

Trouble Code: P1690



Malfunction Indication Light Malfunction

Possible Causes:



Wire from ECM to MIL is shorted or grounded
 
ECM has failed
 
MIL has failed
 

Trouble Code: P1691



Malfunction Indication Light Open

Possible Causes:



Wire from ECM to MIL is shorted or grounded
 
ECM has failed
 
MIL has failed
 

Trouble Code: P1692



Malfunction Indication Light Short to Ground

Possible Causes:



Wire from ECM to MIL is shorted or grounded
 
ECM has failed
 
MIL has failed
 

Trouble Code: P1693



Malfunction Indication Light Short to B+

Possible Causes:



Wire from ECM to MIL is shorted or grounded
 
ECM has failed
 
MIL has failed
 

Trouble Code: P2096



Post Catalyst Fuel Trim System Too Lean (Bank 1)

Possible Causes:



Oxygen sensor (before catalytic converter) is faulty
 
Oxygen sensor (behind catalytic converter) is faulty
 
Oxygen sensor heater (before catalytic converter) is faulty
 
Oxygen sensor heater (behind catalytic converter) is faulty
 
Check circuits for shorts to each other, ground or power
 
ECM has failed
 

Trouble Code: P2097



Post Catalyst Fuel Trim System Too Rich (Bank 1)

Possible Causes:



Oxygen sensor (before catalytic converter) is faulty
 
Oxygen sensor (behind catalytic converter) is faulty
 
Oxygen sensor heater (before catalytic converter) is faulty
 
Oxygen sensor heater (behind catalytic converter) is faulty
 
Check circuits for shorts to each other, ground or power
 
ECM has failed
 

Trouble Code: P2098



Post Catalyst Fuel Trim System Too Lean (Bank 2)

Possible Causes:



Oxygen sensor (before catalytic converter) is faulty
 
Oxygen sensor (behind catalytic converter) is faulty
 
Oxygen sensor heater (before catalytic converter) is faulty
 
Oxygen sensor heater (behind catalytic converter) is faulty
 
Check circuits for shorts to each other, ground or power
 
ECM has failed
 

Trouble Code: P2099



Post Catalyst Fuel Trim System Too Rich (Bank 2)

Possible Causes:



Oxygen sensor (before catalytic converter) is faulty
 
Oxygen sensor (behind catalytic converter) is faulty
 
Oxygen sensor heater (before catalytic converter) is faulty
 
Oxygen sensor heater (behind catalytic converter) is faulty
 
Check circuits for shorts to each other, ground or power
 
ECM has failed
 

Trouble Code: P2101



Throttle Actuator Control Motor Range/Performance

Possible Causes:



TACM wiring harness connector is damaged or open
 
TACM wiring may be crossed in the wire harness assembly
 
TACM (motor) circuit is open, or TACM assembly is damaged (possible open circuit)
 
TACM or the Throttle Valve is dirty
 
Throttle Position sensor has failed
 
ECM has failed
 

Trouble Code: P2123



Accelerator Pedal Position Sensor -D- Circuit High Input

Possible Causes:



Ground between engine and chassis may be broken
 
Throttle position sensor may have failed
 
Accelerator Pedal Position Sensor has failed
 
Throttle position sensor wiring may have shorted
 
Throttle position sensor has failed
 
Faulty voltage supply
 
ECM has failed
 

Trouble Code: P2127



Accelerator Pedal Position Sensor -E- Circuit Low Input

Possible Causes:



Ground between engine and chassis may be broken
 
Throttle position sensor may have failed
 
Accelerator Pedal Position Sensor has failed
 
Throttle position sensor wiring may have shorted
 
Throttle position sensor has failed
 
Faulty voltage supply
 
ECM has failed
 

Trouble Code: P2128



Accelerator Pedal Position Sensor -E- Circuit High Input

Possible Causes:



Ground between engine and chassis may be broken
 
Throttle position sensor may have failed
 
Accelerator Pedal Position Sensor has failed
 
Throttle position sensor wiring may have shorted
 
Throttle position sensor has failed
 
Faulty voltage supply
 
ECM has failed
 

Trouble Code: P2138



Throttle Position Sensor D/E Voltage Correlation

Possible Causes:



ETC TP sensor connector is damaged or shorted
 
ETC TP sensor circuits shorted together in the wire harness
 
ETC TP sensor signal circuit is shorted to VREF (5v)
 
ETC TP sensor is damaged or the ECM has failed
 

Trouble Code: P2181



Cooling System Performance Malfunction

Possible Causes:



ECT sensor has failed
 
ECT Sensor (on Radiator) has failed
 
ECT sensor signal circuit is open (inspect wiring & connector)
 
ECT sensor signal circuit is shorted
 
Cooling system malfunction, or the thermostat is stuck
 
Engine not operating at normal operating temperature
 
EOT sensor is damaged or it has failed
 

Trouble Code: P2400



EVAP Leak Detection Pump (LDP) Control Circuit Open

Possible Causes:



EVAP LDP power supply circuit is open
 
EVAP LDP solenoid valve is damaged or it has failed
 
EVAP LDP canister has a leak or a poor seal
 
ECM has failed
 
EVAP canister system has an improper seal
 
Evaporative Emission (EVAP) canister purge regulator valve 1 has failed
 
Leak Detection Pump (LDP) is faulty
 
Aftermarket EVAP parts that do not conform to specifications
 
EVAP component seals leaking (i.e., leaks in the Purge valve, fuel tank pressure sensor, canister vent solenoid, fuel vapor control valve tube assembly or fuel vapor vent valve).
 

Trouble Code: P2401



EVAP Leak Detection Pump Control Circuit Low

Possible Causes:



EVAP LDP power supply circuit is open
 
EVAP LDP solenoid valve is damaged or it has failed
 
EVAP LDP canister has a leak or a poor seal
 
ECM has failed
 
EVAP canister system has an improper seal
 
Evaporative Emission (EVAP) canister purge regulator valve 1 has failed
 
Leak Detection Pump (LDP) is faulty
 
Aftermarket EVAP parts that do not conform to specifications
 
EVAP component seals leaking (i.e., leaks in the Purge valve, fuel tank pressure sensor, canister vent solenoid, fuel vapor control valve tube assembly or fuel vapor vent valve).
 

Trouble Code: P2402



EVAP Leak Detection Pump Control Circuit High

Possible Causes:



EVAP LDP power supply circuit is open
 
EVAP LDP solenoid valve is damaged or it has failed
 
EVAP LDP canister has a leak or a poor seal
 
ECM has failed
 
EVAP canister system has an improper seal
 
Evaporative Emission (EVAP) canister purge regulator valve 1 has failed
 
Leak Detection Pump (LDP) is faulty
 
Aftermarket EVAP parts that do not conform to specifications
 
EVAP component seals leaking (i.e., leaks in the Purge valve, fuel tank pressure sensor, canister vent solenoid, fuel vapor control valve tube assembly or fuel vapor vent valve).
 

Trouble Code: P2403



EVAP Leak Detection Pump Sense Circuit Open

Possible Causes:



EVAP LDP power supply circuit is open
 
EVAP LDP solenoid valve is damaged or it has failed
 
EVAP LDP canister has a leak or a poor seal
 
ECM has failed
 
EVAP canister system has an improper seal
 
Evaporative Emission (EVAP) canister purge regulator valve 1 has failed
 
Leak Detection Pump (LDP) is faulty
 
Aftermarket EVAP parts that do not conform to specifications
 
EVAP component seals leaking (i.e., leaks in the Purge valve, fuel tank pressure sensor, canister vent solenoid, fuel vapor control valve tube assembly or fuel vapor vent valve).
 

Trouble Code: P2404



EVAP Leak Detection Pump Sense Circuit Range/Performance

Possible Causes:



EVAP LDP power supply circuit is open
 
EVAP LDP solenoid valve is damaged or it has failed
 
EVAP LDP canister has a leak or a poor seal
 
ECM has failed
 
EVAP canister system has an improper seal
 
Evaporative Emission (EVAP) canister purge regulator valve 1 has failed
 
Leak Detection Pump (LDP) is faulty
 
Aftermarket EVAP parts that do not conform to specifications
 
EVAP component seals leaking (i.e., leaks in the Purge valve, fuel tank pressure sensor, canister vent solenoid, fuel vapor control valve tube assembly or fuel vapor vent valve).
 

 
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