Porsche 911 diagnostics
Public library of published fault codes: description, symptoms, probable causes, checks to perform, related parts and direct access to the AI assistant.
Symptoms : Engine warning light, engine running rough, loss of power.
Probable causes : Spark plugs, ignition coils, fuel injectors, air intake, low compression.
Checks to perform : Read the codes cylinder by cylinder, check the spark plugs and ignition coils, check the air intakes, and check compression if necessary.
Do not keep trying to start the engine if it is running very rough, to avoid damaging the catalytic converters.
Probable causes : cylinder 1 spark plug; cylinder 1 ignition coil; fuel injector; compression; wiring harness
Checks to perform : Reverse the coil; check the spark plug; test the fuel injector; measure compression
System: Misfire detected in cylinder 1.
Probable causes : cylinder 2 spark plug; cylinder 2 coil; fuel injector; compression; wiring harness
Checks to perform : Reverse the coil; check the spark plug; test the fuel injector; measure compression
System: Misfire detected in cylinder 2.
Probable causes : cylinder 3 spark plug; cylinder 3 ignition coil; fuel injector; compression; wiring harness
Checks to perform : Reverse the coil; check the spark plug; test the fuel injector; measure compression
System: Misfire detected in cylinder 3.
Probable causes : cylinder 4 spark plug; cylinder 4 coil; fuel injector; compression; wiring harness
Checks to perform : Reverse the coil; check the spark plug; test the fuel injector; measure compression
System: Misfire detected in cylinder 4.
Probable causes : cylinder 5 spark plug; cylinder 5 ignition coil; fuel injector; compression; wiring harness
Checks to perform : Reverse the coil; check the spark plug; test the fuel injector; measure compression
System: Misfire detected in cylinder 5.
Probable causes : cylinder 6 spark plug; cylinder 6 ignition coil; fuel injector; compression; wiring harness
Checks to perform : Reverse the coil; check the spark plug; test the fuel injector; measure compression
System: Misfire detected in cylinder 6.
Probable causes : knock sensor; wiring harness; connector; sensor clamp
Checks to perform : Check connector; measure signal; verify sensor attachment
System: Engine: Low signal from knock sensor 1.
Probable causes : knock sensor; wiring harness; connector; sensor clamp
Checks to perform : Check connector; measure signal; verify sensor attachment
System: Engine: Low signal from knock sensor 2.
Probable causes : crankshaft position sensor; connector; wiring harness; air gap; engine control unit
Checks to perform : Check connector; measure resistance; check wiring harness; verify signal during diagnostics
System: Crankshaft sensor signal or inconsistent engine speed.
Probable causes : camshaft sensor; timing; wiring harness; connector
Checks to perform : Check connector; read actual values; check signal; check timing
System: Engine — Inconsistent camshaft position sensor signal.
Probable causes : secondary air pump; valve; hose; relay; clogged passages
Checks to perform : Test the pump; check the valves; inspect the hoses; read the activation status in the diagnostic system
System: Engine — Secondary Air Injection System Malfunction.
Symptoms : Engine warning light; sometimes there are no unusual sensations.
Probable causes : Oxygen sensor, catalytic converter fatigue, exhaust leak, incorrect air-fuel mixture.
Checks to perform : Check for exhaust leaks, upstream/downstream lambda values, fuel mixture adjustments, and history of misfires.
First check for causes of rich or lean mixtures before concluding that the catalytic converter is the problem.
Probable causes : Worn catalytic converter; oxygen sensor; exhaust leak; incorrect fuel mixture
Checks to perform : Check the oxygen sensors; check for exhaust leaks; check the air-fuel ratio adjustments
System: Engine — Insufficient catalytic efficiency on bank 2.
Probable causes : fuel tank cap; EVAP purge valve; hose; canister; leak
Checks to perform : Check cap; EVAP smoke test; check purge solenoid valve
System: Engine — General EVAP system/tank ventilation fault.
Probable causes : fuel tank cap; hose; canister; solenoid valve
Checks to perform : Check the cap; perform a smoke test; check the hoses
System: Engine. A small leak has been detected in the tank ventilation system.
Probable causes : missing cap; disconnected hose; canister; solenoid valve
Checks to perform : Check the cap; inspect the hoses; perform an EVAP smoke test
System: Engine — A major leak has been detected in the tank ventilation system.
Probable causes : ABS sensor; instrument cluster; wiring harness; vehicle signal
Checks to perform : Read wheel speed sensors; check ABS sensors; inspect the wiring harness
System: Engine. Inconsistent vehicle speed signal.
Probable causes : air intake; throttle body; idle actuator; clogging
Checks to perform : Check intake; clean throttle body; read idle adjustment
System: Engine idle speed is below the setpoint.
Probable causes : air intake; throttle valve; idle actuator; intake hose
Checks to perform : Check air intakes; clean the throttle valve; verify proper fit
System: Engine idle speed higher than the setpoint.
Probable causes : low battery; alternator; ground; DME relay
Checks to perform : Check the battery; measure the alternator output; check the ground connections; check the relays
System: Inconsistent power supply voltage to the engine control unit.
Probable causes : dead battery; alternator; ground; power cable
Checks to perform : measure battery voltage; test the alternator; check ground connections
System: Engine. System voltage too low.
Probable causes : ECU connector; CAN harness; faulty module; power supply
Checks to perform : Read fault codes from all ECUs; check the power supply; inspect the CAN bus
System: Engine — Communication error or CAN timeout, according to the DME.
Probable causes : throttle body; wiring harness; connector; adapter
Checks to perform : Perform throttle adaptation; read throttle angle values; inspect the connector and wiring harness.
System: Engine: Throttle position sensor 1 signal inconsistent.
