What does P0815 Upshift Switch Circuit mean?
The P0815 OBD code refers to a malfunction in the upshift switch circuit.
This code is typically seen in vehicles with paddle shifters, which are used as a type of sport shifter in high-performance models.
When this code is stored, it means that the powertrain control module (PCM) has detected an issue with the transmission gear selection in comparison to the upshift switch input signals or with the voltage in the switch circuit.
Symptoms of this code may include disabled manual upshift function, shift indicator reflecting incorrect gear, or no symptoms at all.
Possible causes include a defective upshift switch, shorted or open circuits in the switch circuit, or a faulty PCM or programming error.
To diagnose and repair this code, a diagnostic scanner, a digital volt/ohmmeter (DVOM), and vehicle-specific diagnostic information are necessary.
Troubleshooting steps involve testing voltage, ground, and signal output at the upshift switch, as well as testing the switch circuits to the PCM or transmission.
If necessary, switches that do not test within system specifications should be replaced.
It's important to address this code as soon as possible, as it indicates a serious electrical issue or mechanical failure.
P0815 Symptoms
- Manual (paddle) upshift function disabled
- Shift indicator reflects incorrect gear
- No symptoms may be exhibited
Possible P0815 Causes
- Defective upshift switch
- Shorted or open circuits in upshift switch circuit
- Faulty PCM or a programming error
Troubleshooting P0815 error code
- Use a diagnostic scanner to retrieve all stored codes and freeze frame data
- Clear the codes and test-drive the vehicle until the PCM enters readiness mode or the code is reset
- If the code is intermittently reset, worsen the conditions to make an accurate diagnosis
- Search vehicle information source for diagnostic flow-charts, connector pin-out charts, connector face views, and component testing procedures/specifications
- Use a digital volt/ohmmeter (DVOM) to test voltage, ground, and signal output at the upshift switch
- If system circuits are functional, test upshift switch circuits to the PCM or transmission
- Test upshift switches as required using vehicle diagnostic information and the DVOM
- Replace switches that do not test within system specifications
