P2602 critical

Coolant Pump Control Circuit Low

The P2602 code means the vehicle's onboard diagnostic system has detected: Coolant Pump Control Circuit Low. This is a critical severity code.

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Keep driving?: No -- stop driving
DIY difficulty: hard
Estimated cost: $250 - $850 (parts and labor)

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Common Symptoms

Engine overheating
Coolant pump not running at full speed
Temperature gauge climbing rapidly
Steam or coolant smell

Probable Causes (Ranked by Likelihood)

Short to ground in pump control circuit Very High
Failed coolant pump motor windings High
Corroded pump connector causing high resistance Moderate
ECM driver circuit shorted low Low

Step-by-Step Diagnostic Procedure

Test pump control circuit for shorts to ground
Measure pump motor winding resistance
Inspect pump connector pins for corrosion
Check ECM pump driver output voltage

Frequently Asked Questions

Why is the pump not running at full speed?

A short to ground in the control circuit or high resistance in the motor windings reduces the voltage and current available to the pump, slowing it down.

Can corroded connectors cause P2602?

Yes. Corrosion increases resistance in the circuit, dropping voltage at the pump motor. This is especially common in vehicles exposed to road salt.

How do I check pump motor windings?

Disconnect the pump and measure resistance across the motor terminals with a multimeter. Compare to manufacturer specifications. Very low or infinite resistance indicates failure.