What does it mean?
This diagnostic trouble code (DTC) is a generic powertrain code and applies to many OBD-II vehicles (1996-newer). This may include, but is not limited to, vehicles from Mercedes-Benz, Jaguar, Range Rover, Ford, Volvo, Sprinter, etc. Although generic, the exact repair steps may vary depending on the year, make, model, and powertrain configuration.
If your vehicle has stored a P0814 code, it means that the Powertrain Control Module (PCM) has detected a malfunction in the transmission range display circuit. This type of code is limited to vehicles with automatic transmissions.
The Transmission Control Module (TCM) may be a standalone module or part of the PCM. The transmission range display sensor is often integrated into the neutral safety switch. The transmission range display sensor is actuated by the shift lever and provides a voltage signal to the PCM and the Instrument Panel Control Module (IPCM) that reflects the specific gear that has been selected. Various engine and transmission outputs are monitored by the PCM to determine if the transmission range display sensor is in the appropriate position. Additionally, the PCM monitors the voltage of the transmission range sensor circuit to ensure it is within established parameters.
If the PCM detects that the vehicle is moving in a way that is not conducive to the gear selection input from the transmission range display sensor or if the circuit voltage is not within allowable parameters, a P0814 code may be stored and a Malfunction Indicator Lamp (MIL) illuminated. Several ignition cycles (with a failure) may be required for the MIL to illuminate.
How severe is this DTC?
A stored P0814 code indicates that a serious electrical problem or a type of mechanical failure has occurred. In any case, the conditions that contributed to the storage of a code of this nature should be rectified as soon as possible.
What are some of the symptoms of the code?
Symptoms of a P0814 fault code may include:
- The gear shift indicator (on the dashboard or console) is inoperative
- The gear shift indicator reflects an incorrect gear
- No start or engine starts with transmission engaged
- No symptoms may appear
What are some common causes of the code?
Causes of this code may include:
- Faulty transmission range display sensor
- Short or open circuits in the transmission range display sensor circuit
- Broken or faulty gear shift indicator
- Faulty PCM or programming error
What are the troubleshooting steps for P0814?
A diagnostic scanner, a digital volt/ohmmeter (DVOM), and a source of vehicle-specific diagnostic information will be needed to diagnose a P0814 code.
You can use your vehicle information source to locate a Technical Service Bulletin (TSB) that matches the vehicle’s year, make, and model; as well as engine size, stored codes, and presented symptoms. If you find one, it may provide useful diagnostic information.
Use the scanner (connected to the vehicle’s diagnostic connector) to retrieve all stored codes and relevant freeze frame data. It is a good idea to record this information before clearing the codes, then test the vehicle until the PCM enters readiness mode or the code resets.
If the PCM enters readiness mode at that point, the code is intermittent and may be much more difficult to diagnose. If this is the case, the conditions that contributed to the code being stored may need to worsen before an accurate diagnosis can be made.
If the code is immediately reset, the next step in your diagnosis will require you to consult your vehicle information source for diagnostic flowcharts, connector pinout diagrams, connector face views, and component testing procedures/specifications.
Step 1
Use the DVOM to test the voltage, ground, and signal output at the transmission range display sensor or neutral safety switch. The input and output circuits of the transmission range display sensor typically consist of either reference voltage (drive gear) or ground (park or neutral).
Step 2
If the system circuits are functional, use the DVOM to test the transmission range display sensor. Replace sensors that do not test according to system specifications.
Transmission range display sensor codes are most often attributed to sensor failure