What are the common causes of P0789?

A shift timing solenoid A connector losing contact. Chafed wiring in the harness. A solenoid A coil failing when hot. Dirty fluid carrying debris. A TCM fault.

Road test and watch shift timing solenoid A data. Wiggle test the connector and harness. Measure the solenoid A resistance hot. Check the fluid level and condition. Replace the solenoid if the signal drops. Clear the code and retest.

P0789

Shift Timing Solenoid A Intermittent

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

What it means

P0789 means Shift Timing Solenoid A Intermittent.

Where it lives

For P0789, start at the solenoid the description names.

Check these first

A shift timing solenoid A connector losing contact
Chafed wiring in the harness
A solenoid A coil failing when hot
Dirty fluid carrying debris
A TCM fault

What to do next

Road test and watch shift timing solenoid A data
Wiggle test the connector and harness
Measure the solenoid A resistance hot
Check the fluid level and condition
Replace the solenoid if the signal drops
Clear the code and retest

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Updated

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