Shift Solenoid B Malfunction
What it means
The transmission control module (TCM) has detected a fault in shift solenoid B. This solenoid works with the other shift solenoids to select the engaged gear, so a fault causes certain gears to be lost or puts the transmission into limp mode.
Symptoms5
- One or more gears missing, or shifts in an unusual order.
- Transmission held in a fixed gear in limp mode.
- Harsh or delayed shifts.
- Higher fuel consumption because upper gears are not reached.
- Check engine light on.
Possible causes6
- Low or dirty transmission fluid.
- Corroded or oil-soaked transmission connector.
- Broken or chafed wire in the solenoid B circuit.
- Failed or sticking shift solenoid B.
- Damaged internal harness or valve body.
- Transmission computer fault (less common).
How to diagnose5
- Read all codes and check for a specific code such as P0756 or P0758 to tell a performance fault from an electrical one.
- Check fluid level and condition.
- Check service information to learn which gears solenoid B takes part in.
- Measure solenoid B resistance and compare it with the manufacturer specification, and inspect the connector and wiring.
- On a road test, watch commanded and actual gear on a scan tool to find the affected shift.
How to fix6
- Top up the fluid, or change it and the filter.
- Clean the connector and repair damaged wiring.
- Replace shift solenoid B or the solenoid pack if it is proven faulty.
- Repair the internal harness or valve body when needed.
- Reprogram or replace the computer after the above is ruled out.
- Clear the codes, then road test through all gears.
Repair cost
In Saudi riyals; the highlighted part is the expected range for this fault.
The cost is low when fluid, a wire or a connector is the cause, and rises when the solenoid is part of a pack replaced as a unit 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
Frequently asked questions
Does a code for solenoid B mean solenoid A is fine?
Usually yes, because the computer monitors each solenoid separately. If codes appear for both at once, look for a shared cause such as the connector, power feed or fluid.
Can solenoid B be replaced on its own?
It depends on the design; some transmissions sell each solenoid separately, while others use one solenoid pack or build them into the valve body.
This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.
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