P0804

DTC P0804, sometimes indicated as P080400 is an OBD diagnostic trouble code indicating a generic fault with the vehicle powertrain (i.e. engine and gearbox). This code identifies an error with the causing 1-4 upshift (skip shift) lamp control circuit malfunction.

This code means that the engine control module (ECM) has detected a problem with the 1-4 gear upshift lamp control circuit. This can be caused by a number of things, including a wiring problem, a bad sensor, or a faulty ECM.
If you have this code, first check the wiring and connectors for any signs of damage or corrosion. Next, check the operation of the 1-4 gear upshift lamp. If it doesn't light up when the gear shift is moved to the 1-4 position, then the problem is most likely the sensor. Finally, if the wiring and sensor are both OK, then the ECM may be bad and needs to be replaced.

• P0804: 1-4 Upshift (Skip Shift) Lamp Control Circuit Malfunction
• P0804: Upshift/Skip Shift Lamp Control Circuit
• P0804: 1-4 Upshift (Skip Shift) Lamp Circuit Malfunction
• P0804: 1-4 Upshift (Skip shift) warning lamp – circuit malfunction
• P0804 00: 1-4 Upshift (Skip shift) warning lamp - circuit malfunction