OBD-II code P0655 indicates a problem with the control circuit for the engine hot (overheat) warning lamp. The powertrain control module (PCM) has detected an electrical fault in the output circuit that activates this warning light on the dashboard.
The bulb or LED in the instrument cluster may be burned out or damaged, preventing the light from illuminating when commanded by the PCM.
Wiring between the PCM and the instrument cluster may be frayed, shorted, open, or corroded, disrupting the signal to the warning light.
A blown fuse or failed relay can interrupt power to the engine hot warning lamp, preventing it from operating correctly.
The instrument cluster itself may have an internal fault, preventing the engine hot warning light from functioning even when the PCM sends the correct signal.
The PCM’s internal output driver for the engine hot lamp circuit may be faulty, though this is uncommon and typically only considered after other causes are ruled out.
No, the PCM is rarely the cause of P0655. The issue is almost always due to a faulty bulb, wiring problem, or instrument cluster failure. Replace the PCM only after all other potential causes have been thoroughly tested and ruled out.
While the vehicle may still be drivable, the engine hot warning light may not function correctly. This could prevent you from being alerted to an actual overheating condition, which can cause severe engine damage. It is recommended to diagnose and repair the issue promptly.
If the light illuminates when the engine is not overheating, it may indicate a short circuit in the wiring or a faulty PCM output signal. This should be diagnosed to prevent false warnings or failure of the light to illuminate during an actual overheat condition.
Yes, a poor or corroded ground connection in the circuit can disrupt the signal to the engine hot warning light, potentially triggering P0655. Always inspect ground connections during diagnosis.