Coolant Pump Control Circuit High
The P2502 code means the vehicle's onboard diagnostic system has detected: Coolant Pump Control Circuit High. This is a critical severity code.
- Keep driving?
- No -- stop driving
- DIY difficulty
- hard
- Estimated cost
- $200 - $800 (parts and labor)
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Common Symptoms
- Engine overheating
- Coolant pump running continuously
- Battery drain when parked
- Check engine light illuminated
Probable Causes (Ranked by Likelihood)
- Short to power in coolant pump control wiring Very High
- Coolant pump relay stuck closed High
- ECM coolant pump driver failure Moderate
- Aftermarket wiring causing voltage feedback Low
Step-by-Step Diagnostic Procedure
-
Check coolant pump relay operation and resistance
-
Inspect control wiring for short to battery voltage
-
Test ECM coolant pump output with bidirectional control
-
Verify coolant pump current draw is within specification
Frequently Asked Questions
Why is my coolant pump running all the time with P2502?
A short to power or stuck relay causes the pump to run continuously, even with the engine off, draining the battery.
Can P2502 drain my battery overnight?
Yes. A continuously running coolant pump can fully drain the battery within a few hours.
How do I test the coolant pump relay?
Remove the relay and check for continuity across load terminals with no power applied. Continuity means contacts are welded shut.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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