P174A BMW Fault Code

Description:

Brake Switch Circuit Input Malfunction Indicates PCM did not receive a brake pedal position (BPP) input. Open or short in BPP circuit Open or short in stoplamp circuits damaged PCM Malfunction in module(s) connected to BPP circuit.

(Rear Electronic Module [REM] Windstar and LS6/LS8 or Lighting Control Module (LCM) Continental and Town Car. Damaged brake switch Misadjusted brake switch Check for proper function of stoplamps.

P174A 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 P174A 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 P174A

P174A 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 P174A code ?

• Damaged ECM
• Clogged or faulty fuel injector (s)
• Camshaft advance mechanism binding (VCT unit)
• Faulty Fuel injector

As the engine heats up and combustion becomes easier and more complete, the PCM will command the idling control valve to increase the amount of air entering the engine to suit the changing conditions.

However, when the load on the engine changes, say, when some electrical consumers or other systems are either turned on or off, the PCM adapts the signal voltage to the idle control valve to ensure that the idling speed remains stable, and at the RPM specified by the manufacturer.