Shift Solenoid B Stuck On

What it means

The transmission control module (TCM) has found that the transmission behaves as if shift solenoid B is on all the time, so a gear other than the commanded one appears. This can cause two gears to be applied at once or hard clunks, which strains the clutches if it continues.

Related codes: P0755P0756P0758P0730

Symptoms4

• A gear that does not suit the current speed, or starting off in a high gear.
• Hard clunks or a feeling of internal braking on some shifts.
• Transmission entering limp mode.
• Check engine light on.

Possible causes5

• Shift solenoid B stuck open because of metal particles or debris.
• Dirty or old transmission fluid.
• Short in the control wire keeping the solenoid energized on some designs.
• Sticking shift valve in the valve body.
• Fault in the driver circuit inside the transmission computer (less common).

How to diagnose4

1. Use a scan tool to see which gear appears instead of the commanded one, and compare it with the solenoid apply chart in service information.
2. Unplug the solenoid or transmission connector and see whether the behavior changes, to tell an electrical short from a mechanical stick.
3. Check the circuit for a short that keeps the solenoid energized.
4. Check fluid condition, the pan and the filter for metal particles.

How to fix5

1. Repair any wiring short.
2. Change the fluid and filter to remove debris.
3. Replace shift solenoid B or the solenoid pack.
4. Clean or replace the valve body if its shift valve is sticking.
5. Clear the codes, run the shift relearn if needed, then road test through all gears.

The cost is low when a wiring short or a replaceable solenoid is the cause, and rises if a full solenoid pack or a valve body is needed.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

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