OBD-II code · Powertrain (generic, extended)
P2603 Coolant Pump Control Circuit Low
The electric coolant pump drive line reads below the lower threshold — typically a short to ground or a failed driver stage.
Is it safe to drive with P2603?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyDrive line shorted to ground
- PossibleDriver stage failed
- Less likelyConnector pins corroded - high contact resistance
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–2.5 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Electric Coolant Pump, Coolant Pump Wiring
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.