U1955 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 U1955. However, it is intended to flash the transmission control indicator lamp (TCIL) for first time VSS circuit error/malfunctions. Refer to possible causes for U1955

U1955 Code Symptoms :

The original multi-displacement system turned off opposite pairs of cylinders, allowing the engine to have three different configurations and displacements. U1955 code had an elaborate diagnostics procedure, including showing engine trouble codes on the air conditionning display. However, the system was troublesome, misunderstood by customers, and a rash of unpredictable failures led to the technology being quickly retired.

Diagnosis And Repairing U1955

U1955 OBD2 specifically refers to the camshaft (cam) timing. In this case, if the cam timing is over-retarded, the engine light will be illluminated and the code will be set.

How to fix U1955 code ?

• Clogged or faulty fuel injector (s)
• Erratic camshaft position due to low oil pressure
• Camshaft advance mechanism binding (VCT unit)
• Variable Camshaft Timing (VCT) position circuit is open or shorted

Gear changes are accomplished by a command from the BMW TCM to energize the clutch actuator to release the clutch; after which various actuators inside the transmission disengage the current gear, and depending on current operating conditions, engage the next higher or lower gear ratio. All of this happens much faster than a human driver could change gears, and in most applications, gear changes are as smooth and seamless as on any fully automatic transmission.