Powertrain, generic · Computer and auxiliary outputs

P0655 Engine Hot Lamp Output Control Circuit

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

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.

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

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

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–400
Time0.5–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

engine hot lampinstrument clusterlamp control circuit

Related codes

P0217P0117P0118P0650P0654

References: law.cornell.edu, saabwisonline.com.