C00B3

Code

Generic C — Chassis

Chassis CAN Bus: Lost Communication with Steering Control Module

Brand: Generic

Type: C — Chassis

Views: UK: 8 EN: 14 RU: 2

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Broken or intermittent CAN bus wiring or connectors (CAN High or CAN Low).
Failed Steering Control Module (internal electronics or firmware).
Loss of module power or ground (fused power feed open, poor ground).
Short to battery or ground on CAN lines, or missing termination.
Network interference, bus-off condition from another module, or software mismatch.

Scan for additional network codes (other modules, gateway, or bus-off codes).
Visually inspect steering module connector and harness for damage, corrosion, water ingress, or pin push‑outs.
Verify module battery feed and ground voltages with key on and engine off.
Measure CAN low/high voltages at the module connector: check idle (recessive) voltage and differential when bus active.
Check termination resistance across CAN H and CAN L (~60 ohms for two 120Ω terminators in parallel).
Use an oscilloscope or CAN bus analyser to capture waveforms and message traffic on the chassis CAN.

CAN recessive voltage ~2.5 V on CAN H and CAN L; dominant differential typically >1.0 V when active.
Common chassis CAN bitrates: 250 kb/s or 500 kb/s (verify vehicle-specific rate).
Expected steering module message frequency: steering angle/torque messages typically 10–100 Hz (vehicle-dependent).
Normal idle bus shows steady ~2.5 V on both wires; repeated corrupted frames or no frames indicate comms loss.
Termination: combined resistance ~60 Ω between CAN H and CAN L with power off.

Retrieve freeze frame and full DTC list; note related network and historical occurrence pattern.
With a scan tool, view live CAN messages and steering module PID data; attempt to observe steering angle or status messages.
Clear codes, road test or stress the harness (steering column movement, vibration) and re-scan to reproduce the fault.
Inspect and secure connectors at the steering module, nearby junctions, and the CAN gateway. Repair or replace damaged pins/wiring.
Check supply voltage and ground at the steering module connector; repair open circuits or poor grounds before further testing.
Measure termination resistance across CAN H/L with battery disconnected; confirm ~60 Ω. Repair missing or shorted termination.
Use an oscilloscope or CAN sniffer to confirm physical layer waveforms and to verify the steering module is transmitting/receiving frames. Identify bus errors or a bus‑off node.
If the module is not transmitting but has correct power/ground and the bus is healthy, consider reflashing software or replacing the steering control module per manufacturer procedures.
After repairs, clear codes and verify normal operation and message presence on the bus; confirm related systems (EPS, ESC) behave correctly.