U0508 BMW Fault Code

Description:

BMW Mass Air Flow (MAF) Sensor Intermittent The MAF sensor circuit is monitored by the PCM for sudden voltage (or air flow) input change through the comprehensive component monitor (CCM).

If during the last 40 warm-up cycles in key ON engine running the PCM detects a voltage (or air flow) change beyond the minimum or maximum calibrated limit, a continuous memory diagnostic trouble code (DTC) is stored.

U0508 Code Symptoms :

If your vehicle failed a U0508 test and the U0508 Check Engine Light is NOT on, chances are you have a problem with the OBDII system, a burned out MIL lamp, or a faulty catalytic converter. The converter is essentially an afterburner that cleans up the exhaust after it exits the engine. The OBDII system uses U0508 a ownstream oxygen sensor to monitor the efficiency of the converter, and it should detect a drop in converter efficiency if the converter has been contaminated or is failing (ignition misfiring, leaky exhaust valves, and oil burning can all damage the converter). What you want to look : Any conditions that might cause ignition misfire, an overly rich or lean fuel condition, or loss of compression.

Diagnosis And Repairing U0508

U0508 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 U0508 code ?

• Failures of clutch motion/travel sensors.
• Faulty spark plug (s)
• EVAP system hose leaking
• Variable Camshaft Timing (VCT) position circuit poor electrical connection

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.