C157C BMW Fault Code

Description:

The issue covered by the bulletin involves a power steering noise/whine or fluid leak from the power steering pump, gear or high pressure side power steering hose during extreme low outdoor temperature operation.

C157C 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 C157C 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 C157C

C157C OBD2 may also be triggered by faults earlier down the line. For example, a dirty MAF sensor might be causing the car to overcompensate in its fuel-trim adjustments. As a result, oxygen sensors are likely to report fuel mixture problems.

How to fix C157C code ?

• Continuous oil flow to the VCT piston chamber
• EVAP system hose leaking
• Engine Control Module (ECM)
• Fuel injector leaks

In most cases, the TCM is integrated into a single housing with the BMW PCM. Nevertheless, the section of the module which controls (automatic) transmission function may be powered up separately.

In any case, the TCM is typically powered using switched (only present with the ignition switch in the ON, start, or run position) voltage. This circuit is normally equipped with a fuse, fusible link, and/or a relay. Frequently, the PCM and TCM are powered using the same relay albeit by separate circuits. Access to a reliable vehicle information source will yield necessary details of the TCM power circuit for the specific vehicle in question.