What are the common causes of P27A2?

An open in the auxiliary transmission fluid pump B control circuit. A short in the auxiliary transmission fluid pump B control circuit. A corroded auxiliary transmission fluid pump B connector. A failed auxiliary transmission fluid pump B.

Read auxiliary transmission fluid pump B status on a scan tool. Command auxiliary transmission fluid pump B on and off. Test the auxiliary transmission fluid pump B control circuit for open and short faults. Check the auxiliary transmission fluid pump B connector pins. Replace the auxiliary transmission fluid pump B if the circuit tests good. Clear the code and retest.

P27A2

Electric/Auxiliary Transmission Fluid Pump B Control Circuit/Open

System: Transmission (P code)
Lamp: Check Engine Light
Category: Powertrain - Transmission

What it means

P27A2 means Electric/Auxiliary Transmission Fluid Pump B Control Circuit/Open.

Where it lives

For P27A2, the circuit described runs through the pump. The description of P27A2 reports the pump as open.

Check these first

An open in the auxiliary transmission fluid pump B control circuit
A short in the auxiliary transmission fluid pump B control circuit
A corroded auxiliary transmission fluid pump B connector
A failed auxiliary transmission fluid pump B

What to do next

Read auxiliary transmission fluid pump B status on a scan tool
Command auxiliary transmission fluid pump B on and off
Test the auxiliary transmission fluid pump B control circuit for open and short faults
Check the auxiliary transmission fluid pump B connector pins
Replace the auxiliary transmission fluid pump B if the circuit tests good
Clear the code and retest

Look up another code

Code or symptom

Enter a full code or a symptom. Press / to search. How to read a code

Type a code above, or start from a symptom or a common code.

Updated

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