C0770

Code

Generic C — Chassis

Steering Column Lock Control Circuit Malfunction

Brand: Generic

Type: C — Chassis

Views: UK: 15 EN: 29 RU: 18

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Blown fuse or faulty relay supplying the steering column lock circuit
Damaged, corroded, or disconnected wiring or connector(s) at the steering column lock actuator
Faulty steering column lock actuator or lock motor
Intermittent open or short to battery/ground on control or supply circuits
Faulty body or chassis control module (BCM) or steering column module
CAN bus or data communication error between modules

Symptoms

Steering wheel remains locked or intermittently locks/unlocks
Vehicle may not start if immobilizer/lock prevents key cycle
Steering lock warning, security, or check messages on dash
No audible click or movement when attempting to unlock the steering column
Stored or pending DTCs related to body/steering modules or CAN communication

What to check

Retrieve freeze frame and full list of codes with a scan tool; note any related U codes or body module errors
Inspect fuses and relays for the steering column lock circuit
Visually inspect wiring harness and connectors at the steering column for corrosion, damage, or disconnected pins
Check battery voltage and supply while commanding lock/unlock (voltage should be ~12V to 14.5V)
Backprobe connector at the lock actuator while commanding lock/unlock to confirm control, supply and ground signals
Check for CAN bus errors or lost communication messages between BCM and steering column module

Signal parameters

Supply voltage to actuator: battery voltage (nominal 11.5–14.5 V) when powered
Ground continuity: near 0 ohms to chassis ground
Control signal voltage: varies by design (0–12 V switch or PWM) — observe change when commanding lock/unlock
Actuator resistance: compare with factory spec (typical few ohms to hundreds of ohms for motor/coils)
CAN bus idle voltage: approx. 2.5 V differential bias on CAN_H/CAN_L (check module comms)

Diagnostic algorithm

Obtain stored codes and vehicle-specific freeze frame data with a scan tool; note related communication codes (U-codes)
Verify battery voltage is stable and above 12V during tests; recharge or charge if low
Inspect fuses and relays in instrument and body fuse boxes; replace any blown fuses and retest
Visually inspect connectors and wiring at the steering column lock for corrosion, bent pins, or damage; repair as needed
Backprobe the actuator connector while commanding lock/unlock from scan tool: verify supply (battery), ground, and control signal change. If no supply, trace back to fuse/relay/BVSM/BCM
If control signals are present but actuator does not move, disconnect and bench-test actuator (apply correct supply and ground) to confirm mechanical/electrical failure
If actuator is confirmed good but module commands do not reach the actuator, check harness continuity and resistance between module pin and actuator pin; repair any opens or shorts
Check for communication errors on the CAN bus and verify module presence/response in the scan tool; if a module is unresponsive, troubleshoot CAN wiring and termination
After repairs, clear codes and perform functional test of steering lock operation; road test or cycle ignition several times to confirm issue resolution

Likely causes

Corroded connector at the steering column (common location)
Shorted control wire to battery or chassis ground from recent repairs or routing near sharp edges
Failed steering lock actuator motor due to age or water ingress
Blown fuse in instrument or body fuse box protecting the lock circuit

Fault status

⚠️ Status

Steering Column Lock Control Circuit Malfunction — an electrical or communication fault was detected in the steering column lock control circuit. The lock may not operate correctly until the cause is repaired.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0 - 3.0 hours