P2602
Coolant Pump Control Circuit Low
- Severity
- High
- Driving
- Drivable — book it in
The coolant pump control circuit is reading low - typically shorted to earth or an open circuit. The module cannot control the pump, so coolant may not circulate when it should, or the pump may run when it should not and flatten the battery.
Possible causes
- CommonFailed electric coolant pump
- CommonCorroded connector or damaged wiring
- CommonBlown fuse or failed relay
- CommonAir lock in the cooling system after a previous repair
- CommonLow coolant level
- PossibleDebris or scale jamming the pump impeller
- RareFailed control module driver
What you might notice
- Engine running hot
- Temperature gauge climbing, particularly in traffic
- Heater blowing cool
- Coolant warning
- Check engine light on
- On a turbocharged engine, the pump running after switch-off may have stopped
What to check, in order
- Disconnect the pump and check whether the low reading persists at the harness.
- Watch the temperature gauge and stop if it climbs. An engine without coolant circulation overheats quickly, and overheating damage is expensive and permanent.
- Check the coolant level when the engine is cold. Never open a hot cooling system - it is pressurised and above its normal boiling point.
- Check the fuse and relay for the pump circuit before anything else.
- Listen for the pump. Many run at ignition-on and continue after switch-off, so silence when one should be running is a clear finding.
- Check for an air lock if the cooling system has been opened recently - an air-locked pump cannot circulate coolant even though it is running.
- Inspect the connector for corrosion.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
P00xxP01xxP02xxP03xxP04xxP05xxP06xxP07xxP08xxP09xxP0AxxP0BxxP0CxxP0DxxP0ExxP0FxxP10xxP11xxP12xxP13xxP14xxP15xxP16xxP17xxP18xxP19xxP1AxxP1BxxP1CxxP1DxxP1ExxP1FxxP20xxP21xxP22xxP23xxP24xxP25xxP26xxP27xxP28xxP29xxP2AxxP2BxxP2CxxP2DxxP2ExxP2FxxP30xxP31xxP32xxP33xxP34xxP35xxP36xxP37xxP38xxP39xxP3AxxP3BxxP3CxxP3DxxP3ExxP3Fxx
Computer output circuits and control module
P2600P2601P2602P2603P2604P2605P2606P2607P2608P2609P2610P2611P2612P2613P2614P2615P2616P2617P2618P2619P2620P2621P2622P2623P2624P2625P2626P2627P2628P2629P2630P2631P2632P2633P2634P2635P2636P2637P2638P2639P2640P2641P2642P2643P2644P2645P2646P2647P2648P2649P2650P2651P2652P2653P2654P2655P2656P2657P2658P2659P2660P2661P2662P2663P2664P2665P2666P2667P2668P2669P2670P2671