P3981 BMW Fault Code
Check P3981 OBD Fault Code ReasonFuel Rail Pressure Sensor in Range But Low The comprehensive component monitor (CCM) monitors the FRP pressure for acceptable fuel pressure. The test fails when the fuel pressure falls below a calibrated value.
Low fuel pressure Damaged BMW FRP sensor Excessive resistance in circuit Low or no fuel A FRP PID value below 551 kpa (80 psi) indicates a failure Low or no fuel A FRP PID value greater than 896 kpa (130 psi) indicates a failure.
P3981 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 P3981 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 P3981
P3981 the main thing to check is to verify the operation of the VCT solenoid. You're looking for a sticking or stuck VCt solenoid valve caused by contamination. Refer to vehicle specific repair manual to perform component tests for the VCT unit.
How to fix P3981 code ?
- 1Camshaft Position Sensor circuit poor electrical connection
- Dirty Oil
- Insufficient cylinders compression
- Fuel injectors harness is open or shorted
Regardless of the design though, the purpose of all clutch actuating systems is to improve the driving experience by removing the need for manual clutch operation by the driver.
Computer-controlled clutch actuating systems work particularly well in dual clutch systems where one clutch controls gear changes of even-numbered gear ratios, and a second clutch that controls gear changes of odd-numbered ratios.