What it means
The shift motor exceeds the calibrated maximum speed. Mechanical load lost or rotor position offset.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The shift motor moves the transmission gear actuator, and the control module monitors motor speed and position as it follows a shift command. This code sets when the motor spins faster than its calibrated maximum, which can happen if a broken coupling removes the actuator load or the rotor position signal is offset.
Common causes
Most likely first.
- Mechanical coupling broken - load lost
- Rotor position sensor offset
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
How to diagnose it
- Review freeze-frame and live motor speed, rotor position, and commanded actuator movement to see whether overspeed occurs with a particular shift.
- Inspect the shift motor coupling and actuator linkage for breakage, looseness, or separation that could leave the motor unloaded.
- Check the rotor position sensor connector and wiring for damage or poor contact that could produce an offset reading.
- Compare rotor position and motor speed signals with the manufacturer's specification to distinguish a lost mechanical load from a sensor offset.
- Repair the confirmed coupling or sensor circuit fault, then verify motor speed and actuator travel during commanded shifts.
Common fixes
- Reconnect or replace a broken shift motor coupling using the specified procedure.
- Repair loose or damaged rotor position sensor wiring and connector terminals.
- Correct rotor position sensor offset using the manufacturer's procedure.
- Replace a failed position sensor or shift motor only when testing confirms the fault.
Can I keep driving?
If the transmission shifts unpredictably, slips, or is locked in one gear, avoid driving because the module may not know the shift motor's true movement. If it remains controllable, restrict driving to reaching a safe location and arrange diagnosis.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.