C0620 indicates an open circuit fault in the variable effort steering (VES) system's locksafety actuator control circuit. The steering system's computer cannot communicate with or control the steering assist actuator, often disabling variable steering effort and triggering a warning light.
The electric actuator motor inside the steering column has failed, creating an open circuit. This is the most common actual failure.
Broken, chafed, or melted wiring in the steering column harness (common due to steering movement) causes an open circuit.
Electrical connectors at the steering column become corroded, oxidized, or backed out, breaking the circuit path.
The dedicated steering control module that manages variable effort steering has failed internally.
Related sensors that provide input to the steering system may cause the circuit to read as open if they fail.
The engine/powertrain control module rarely fails, but a software or hardware issue could theoretically cause this code.
The vehicle remains driveable, but steering may feel unnaturally heavy or constant regardless of speed. The steering lock mechanism may also be affected, which could have safety implications.
The locksafety system is designed to prevent steering lock engagement while the vehicle is moving. However, the fault should still be repaired promptly.
Almost never. The PCM/ECM is very rarely the cause of C0620. The actual failure is almost always the actuator, wiring, or connectors in the steering column. Always diagnose the circuit properly before considering an expensive control module replacement.
Costs vary significantly by vehicle. Actuator replacement can range from $200-800 parts plus labor, while wiring repairs may be considerably less. Luxury vehicles with complex steering systems can be more expensive.