C3901 BMW Fault Code
Check C3901 OBD Fault Code ReasonEngine Coolant Temperature (ECT) Circuit High Input Indicates the sensor signal is greater than Self-Test maximum. The ECT sensor maximum is 4.6 volts or -50 C (-58 F). Note on some vehicles that are not equipped with an ECT sensor, CHT can be used and can set this DTC. Open circuit in harness Sensor signal short to power Damaged PCM Improper harness connection Damaged sensor ECT V PID reading greater than 4.6 volts with key ON and engine OFF or during any engine operating mode indicates a hard fault.
C3901 Code Symptoms :
There are currently two main types of cylinder deactivation used today, depending on the type of engine. C3901 code for the pushrod design which uses solenoids to alter the oil pressure delivered to the lifters. In their collapsed state, the lifters are unable to elevate their companion pushrods under the valve rocker arms, resulting in valves that cannot be actuated and remain closed.
Diagnosis And Repairing C3901
C3901 OBD2 specifically refers to the camshaft (cam) timing. In this case, if the cam timing is over-retarded, the engine light will be illluminated and the code will be set.
How to fix C3901 code ?
- Camshaft advance mechanism binding (VCT unit)
- Continuous oil flow to the VCT piston chamber
- Faulty variable valve timing (VVT)
- Improper ignition timing
