What are the common causes of P261B?

A coolant pump B that will not run when commanded. A weak coolant pump B motor. Intermittent power in the pump B control circuit. A pump B relay that does not latch.

Command coolant pump B on a scan tool and watch temperature. Test the pump B control circuit under load. Check the pump B relay and fuse. Confirm power and ground at the pump B connector. Replace coolant pump B if it will not run when commanded. Clear the code and retest.

P261B

Coolant Pump B Control Circuit Performance/Stuck Off

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

What it means

P261B means Coolant Pump B Control Circuit Performance/Stuck Off.

Where it lives

For P261B, start at the pump the description names.

Check these first

A coolant pump B that will not run when commanded
A weak coolant pump B motor
Intermittent power in the pump B control circuit
A pump B relay that does not latch

What to do next

Command coolant pump B on a scan tool and watch temperature
Test the pump B control circuit under load
Check the pump B relay and fuse
Confirm power and ground at the pump B connector
Replace coolant pump B if it will not run when commanded
Clear the code and retest

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Updated

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