B204C BMW Fault Code

Description:

Vehicle Speed Sensor (VSS) Intermittent Indicates the powertrain control module (PCM) detected an error in the vehicle speed information. Vehicle speed data is received from either the vehicle speed sensor (VSS), transfer case speed sensor (TCSS), anti-lock brake system (ABS) control module, generic electronic module (GEM), or central timer module (CTM). This DTC is set the same way as B204C. However, it is intended to flash the transmission control indicator lamp (TCIL) for first time VSS circuit error/malfunctions. Refer to possible causes for B204C

B204C 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 B204C 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 B204C

Parts or components should not be replaced with reference to only a B204C DTC. The vehicle service manual should be consulted for more information on possible causes of the fault, along with required testing.

How to fix B204C code ?

• Clogged or faulty fuel injector (s)
• Erratic camshaft position due to low oil pressure
• Fuel injectors harness is open or shorted
• Variable Camshaft Timing solenoid stuck open

A good starting point in your diagnosis is checking all system fuses and fusible links. This can be done using the BMW DVOM on the voltage setting. You will want to test the fuses with circuits loaded.

Some fuses will appear normal until a load is placed on their respective circuit; at which point they will fail. This has been the cause of many 'phantom malfunctions'. Consult your vehicle information source for fuse and fusible link locations. If all fuses are in working order, you may want to check TCM relay operation by swapping identical relays. Usually the horn relay, starter relay, fuel pump relay, air conditioning clutch relay, and controller relays are similar enough in design to swap for diagnostic purposes.