U2129 BMW Fault Code

Description:

Intake Manifold Runner Control Malfunction (Stuck Open) The IMRC system is monitored for failure during continuous, key ON engine OFF or key ON engine running self-test. The test fails when the signal on the monitor pin is less than an expected calibrated range at closed throttle. IMRC monitor signal circuit shorted to BMW PWR GND or SIG RTN Damaged IMRC actuator Damaged PCM An IMRCM PID reading approximately near 1 volt at closed throttle may indicate a fault.

U2129 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 U2129 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 U2129

Parts or components should not be replaced with reference to only a U2129 DTC. The vehicle service manual should be consulted for more information on possible causes of the fault, along with required testing.

How to fix U2129 code ?

• EVAP canister or fuel tank leaks
• Faulty Air Flow Meter
• Faulty oil control valve (OCV)
• Faulty variable valve timing (VVT)

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.