What are the common causes of P26CD?

Coolant pump control wire shorted to voltage. Failed coolant pump. Corroded coolant pump connector. ECM driver fault holding the circuit high. Open in the coolant pump ground.

Command the engine coolant pump with a scan tool. Test the coolant pump control wire for a short to voltage. Inspect the coolant pump connector. Measure the coolant pump motor resistance. Verify the control output at the ECM. Clear the code and retest.

P26CD

Engine Coolant Pump Control Circuit High

System: Computer output circuits (P code)
Lamp: Check Engine Light
Category: Powertrain - Computer and Auxiliary Controls

What it means

P26CD means Engine Coolant Pump Control Circuit High.

Where it lives

For P26CD, the pump sits on the circuit this code reports. The description of P26CD reports a fault at the pump.

Check these first

Coolant pump control wire shorted to voltage
Failed coolant pump
Corroded coolant pump connector
ECM driver fault holding the circuit high
Open in the coolant pump ground

What to do next

Command the engine coolant pump with a scan tool
Test the coolant pump control wire for a short to voltage
Inspect the coolant pump connector
Measure the coolant pump motor resistance
Verify the control output at the ECM
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.