The engine module switches this hard-wired output with its own driver and checks the circuit electrically (open, short to ground or voltage) – it cannot see whether the lamp lights; on CAN-based cars such faults appear as U codes. P0655 concerns the engine hot or coolant warning lamp that the engine module switches by wire from the coolant temperature signal. CARB links overtemperature protection strategies to this lamp: a protective reaction that only starts after the hot lamp lights needs no MIL. No manufacturer document available to us uses this code; the description follows CARB and the component. If the circuit fails, the driver may not be warned of overheating – check it promptly even though the check engine light usually stays off. Actual overheating is P0217; the coolant sensor circuit is P0117/P0118.
Medium severity. Can I keep driving?If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
Symptoms
- Temperature warning lamp does not light at bulb check or when overheating
- Warning lamp stays on without overheating
- Code stored, check engine light depending on the maker
Most likely causes
- Wire or connector between module and receiver open, corroded or shorted
- Bulb/LED or instrument cluster faulty
- Lamp supply missing (fuse)
- Output driver in the module faulty
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
What each character of P0655 means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 6: Control modules and outputs
- 55: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0655?
If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
What causes code P0655?
The most common causes are: wire or connector between module and receiver open, corroded or shorted; bulb/LED or instrument cluster faulty; lamp supply missing (fuse).
Related codes
- P0217Engine Coolant Over Temperature Condition
- P0117Engine Coolant Temperature Sensor 1 Circuit Low
- P0118Engine Coolant Temperature Sensor 1 Circuit High
- P0650MIL Control Circuit/Open
- P0654Engine RPM Output Circuit/Open
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.