1. Fault code: P0340 - No camshaft signal
2. Fault code: P0341 - Unreliable camshaft signal
3. Fault code: P0008 - Only camshaft signal working mode
Fault code explanation:
Regarding the camshaft fault codes:
1. Most camshaft sensors use Hall effect sensors. When the signal wheel passes the sensor, there is a corresponding change in signal voltage. The ECU uses this signal and compares it with the tooth gap position of the crankshaft sensor to determine the top dead center (compression top dead center or exhaust top dead center) of one cylinder.
2. Under normal circumstances: The adjacent two phase signals should have regular changes between high and low voltages, that is: 01-01-01 or 10-10-10.
3. Note: Signal waveform, signal voltage threshold, phase relationship;
1.1. P0340 - No camshaft signal
Operating conditions: Engine running process] Engine startup process
Conditions for setting DTC: ECU does not receive the camshaft signal
The effective edge of the phase signal received by the system (there is a signal but does not match the system pulse spectrum) that is, the two adjacent signal sampling windows have a signal that remains unchanged (the state is always 00-00-00 or 11-11-11)
Fault cause:
Incorrect installation position of the signal disc
Camshaft signal is interfered with
Camshaft sensor ground wire open circuit
Camshaft signal line open circuit or ground short circuit
Camshaft sensor signal line short-circuited to high voltage
Failure mode:
Engine fault light is on
Engine speed and torque are limited or speed limited torque is not limited
Cruise, exhaust braking failure;
1.2. Fault code P0341 - Unreliable camshaft signal
Operating conditions: Engine running or startup process
Fault setting conditions: The system receives the effective edge of the camshaft signal (there is a signal but does not meet the requirements), and the two adjacent signal sampling windows are unstable (the state is like 00-10 or 10-11)
Fault cause: Poor contact in the signal circuit, etc.
Failure mode:
Gasoline engine: Perform group ignition in sequence, try ignition in the starting condition
Adjust the detonation control method, use the specified cylinder's detonation threshold control, since it is impossible to distinguish and control all cylinders, to avoid risks, take the most sensitive value to control all cylinders (gasoline vehicle);
1.3. P0008 - Only camshaft signal working mode
Operating conditions: Engine startup or engine running process
Conditions for setting DTC: Engine control unit ECU does not receive the crankshaft signal
Failure mode: Engine speed and torque are limited or speed limited torque is not limited