P074A BMW Fault Code
Check P074A OBD Fault Code ReasonBMW HO2S Sensor Circuit Malfunction (HO2S-11) During testing the HO2S Heaters are checked for opens/shorts and excessive current draw.
The BMW test fails when current draw exceeds a calibrated limit and/or an open or short is detected. Short to VPWR in harness or HO2S. Water in harness connector. Open VPWR circuit. Open GND circuit. Low battery voltage. Corrosion or poor mating terminals and wiring Damaged HO2S heater. Damaged PCM.
P074A Code Symptoms :
The original multi-displacement system turned off opposite pairs of cylinders, allowing the engine to have three different configurations and displacements. P074A 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 P074A
P074A 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 P074A code ?
- Damaged camshaft position (CMP) sensor
- Faulty starter motor
- Improper ignition timing
- Failures of clutch motion/travel sensors.
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.
