What it means
The control module detects movement of shift fork C that does not match the commanded movement. The code identifies unexpected movement; the cause may be electrical or mechanical.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Shift fork C moves a gear-engaging sleeve and should stay in the position the transmission control module commands. The module compares fork C's position feedback with that command and sets this code when the fork moves unexpectedly, which can happen if its actuator leaks internally or its detent spring or ball no longer holds position.
Common causes
Most likely first.
- Internal leak in fork actuator
- Detent spring or ball failed
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
- Read freeze-frame and live transmission data to find when fork C moved without a matching command and which gear was affected.
- Inspect accessible fork C actuator connectors and wiring for damage or poor contact that could make the reported position erratic.
- Compare fork C commanded and reported positions during a suitable scan-tool check to establish whether the movement is real or a feedback fault.
- Check the fork C actuator for signs of internal leakage using the manufacturer's diagnostic procedure.
- If the actuator and feedback circuit check out, inspect the fork C detent spring and ball for failure or loss of retention.
Common fixes
- Repair damaged or loose fork C actuator wiring or connectors.
- Repair or replace a fork C actuator with confirmed internal leakage.
- Replace a failed fork C detent spring or ball.
- Repair any internal fork C mechanism damage found during inspection.
Can I keep driving?
Avoid driving if the transmission unexpectedly changes gear, slips, or enters limp mode; uncontrolled fork C movement can disrupt gear engagement. If shifting is abnormal, stop in a safe place and arrange diagnosis or recovery.
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.