P2603Coolant Pump A Control Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P2603 means the drive line of electric coolant pump A reads high - usually a short to the supply side, or an overcurrent seen by the driver stage. Ford's 2020-2023 gasoline OBD summary assigns pump A to the auxiliary high-temperature loop for cabin heating and sets P2602/P2603 when the smart driver reports a fault within 5 s. For the 3.6 L LLT, GM's 2008 table checks the after-run pump for a circuit fault to voltage (pending code only, no warning light). VW's 2014 books use a current threshold: about 0.60-1.20 A on the Passat and CC, 5.5-10 A on the Touareg. Under CARB, output components need monitoring for circuit faults. P2600 is the open circuit, P2601 performance, P2602 the low-side fault. Heater output or after-run cooling may be lost.
- What you may notice
- Fault code stored; MIL depends on the maker (GM 2008 LLT table none, GM 2023 ECM table Type B)
- Weak cabin heating
- Higher coolant temperature after hot shutdown
- Likely causes
- LikelyControl wire shorted to battery voltage
- PossibleSeized or sluggish pump drawing excessive current
- RareFaulty driver stage in the ECM
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €60 – €500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.