C12DF BMW Fault Code
Check C12DF OBD Fault Code ReasonVariable Cam Timing Over-advanced (Bank 1) The comprehensive component monitor (CCM) monitors the VCT position for an over-advanced camshaft timing.
The test fails when the camshaft timing exceeds a maximum calibrated value or remains in an advanced position.
BMW cam timing improperly set No oil flow to the VCT piston chamber Low oil pressure VCT solenoid valve stuck closed Camshaft advance mechanism binding (VCT unit) C12DF DTC is a check of the VCT unit.
C12DF Code Symptoms :
While fuel economy was increased, acceleration was seriously compromised, and the loss of engine vacuum led to a dangerous loss of braking assist when the C12DF code system was in four-cylinder mode. In addition to these issues, while the company proposed a hydraulically controlled system that could be switched from within the car, the version they implemented had to be manually changed in the engine compartment using hand tools.
Diagnosis And Repairing C12DF
Parts or components should not be replaced with reference to only a C12DF DTC. The vehicle service manual should be consulted for more information on possible causes of the fault, along with required testing.
How to fix C12DF code ?
- Erratic camshaft position due to low oil pressure
- Faulty oil control valve (OCV)
- Faulty spark plug (s)
- Faulty front heated oxygen sensor
On some transmissions, such as automated manual transmissions or automatic transmissions with manual mode, the GSP switch lets the TCM know whether or not the driver has selected automatic or manual function.
On manual transmissions, the GSP switch informs the TCM which gear the driver is selecting, and may function as a neutral safety switch, depending on system design. The TCM also uses the gate select position switch to monitor transmission operation. For example, if the driver selects manual mode and selects 3rd gear on an automatic transmission, the TCM may monitor speed sensors to detect clutch and brake slippage.
