C0621Variable Effort Steering Lock/Safety Actuator Control Circuit Low
- Generic OBD-II code · Chassis
- Can trigger limp mode
- How the car detects it
- C0621 reports the lock or safety actuator line held too low. In JTEKT's variable-ratio design a PNP transistor switches the lock coil, and the ECU holds the line low on purpose when it wants to lock, for instance after a motor or sensor fault or a broken cable. An unintended short to ground therefore looks like a permanent lock request: the solenoid cannot lift the arm, and the steering stays mechanically coupled. GM's active front steering patent locks the motor electrically first and falls back to the mechanical lock if that has not happened within about 42 ms. No maker publishes C0621. The car steers normally but without the variable feature, and a warning appears.
- What you may notice
- Variable ratio or effort function off
- Steering warning lamp or message
- Likely causes
- LikelyLock solenoid wire shorted to ground in the column or gear harness
- PossibleShorted turns in the lock solenoid
- RareFailed drive transistor in the steering module
- Repair
- Hard · Usually a job for a workshop.Typical cost: €30 – €2,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.