C127A BMW Fault Code

Description:

Catalytic converters must be warm before they can work properly. On a cold start the PCM provides a rich mixture to keep the cold engine running.
All that extra fuel goes into the catalytic converter. But the exhaust isn't very hot, because, ah, the engine is pretty cold. GM has employed several strategies to fire up the catalytic converter quicker and reduce cold start emissions. One way is to use a secondary air pump that pumps outside air directly into the catalytic converter.

C127A Code Symptoms :

The rule of C127A code when it comes to emissions-related vehicle repair is that any modification that changes the vehicle from a certified configuration to a non-certified configuration is considered tampering: this applies to both vehicle owners and repair facilities and is, therefore, a Federal offense. Replacing a catalyst with a straight pipe is one traditional example of C127A.

Likewise, overriding the OBD system through the use of high-tech defeat devices or non-certified computer chips, for example, would also be considered tampering. The OBD system may, however, be repaired back to its original certified configuration with certified performance chips or appropriate aftermarket parts.

Diagnosis And Repairing C127A

Parts or components should not be replaced with reference to only a C127A DTC. The vehicle service manual should be consulted for more information on possible causes of the fault, along with required testing.

How to fix C127A code ?

• Air fuel ratio (A/F) Sensor 1 Bank 1 harness is open or shorted
• Continuous oil flow to the VCT piston chamber
• Fuel tank leaking
• Incorrect fuel filler cap used

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.