P0D73 BMW Fault Code
Check P0D73 OBD Fault Code ReasonThe Transmission Range Sensor (also referred to as the PRNDL input an/or neutral safety switch) tells the transmission control module (TCM) an the engine control module (PCM) that the transmission is in park, reverse, neutral, drive, low, 2nd, 3rd etc. It is attached directly to the manual valve of transmission, so when the shift lever is moved from park to drive, the Transmission Range Sensor communicates this critical information to the above mentioned vehicle control module systems.
P0D73 Code Symptoms :
![See P0D73 in engine](../obd/35.jpg)
The original multi-displacement system turned off opposite pairs of cylinders, allowing the engine to have three different configurations and displacements. P0D73 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 P0D73
P0D73 OBD2 reports a sensor fault, replacement of the sensor is unlikely to resolve the underlying problem. The fault is most likely to be caused by the systems that the sensor is monitoring, but might even be caused by the wiring to the sensor itself.
How to fix P0D73 code ?
![See P0D73 repair manual](../obd/17.jpg)
- Engine Control Module (ECM)
- EVAP canister or fuel tank leaks
- Faulty ignition coil (s)
- EVAP canister or fuel tank leaks
As long as the throttle plate remains closed, the idling speed and quality is controlled by the PCM via the idle control valve, and as can be seen from the above it should be clear that idle control on a gasoline engine is a complex affair.
For instance, if the engine is started in sub-zero temperatures, the PCM will command the idling control valve to allow less air to enter the engine to enrich the air/fuel mixture to create a condition which is roughly analogous to how chokes worked on carburetted engines to control idling in cold weather.