B13C9

Code

Generic B — Body

Steering Column Control Module: Internal Fault

Brand: Generic

Type: B — Body

Views: UK: 12 EN: 12 RU: 10

AI status

Completed

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Page language: EN

Causes

Internal electronics or firmware failure inside the steering column control module
Loss of or intermittent power supply (battery/IGN-switched feed) to the module
Poor ground or high-resistance ground connection at the module
Corroded, damaged or loose connector pins/wiring to the module
Water intrusion or physical damage to the module or connector
CAN/LIN communication faults (open/short/terminator issue) or excessive bus noise

Symptoms

Malfunction indicator or body/control module warning lamp illuminated
Loss or intermittent operation of steering column functions (electronic column lock, adjust, steering wheel switches, horn)
Related systems report faults (stability control/ABS complaining about steering angle sensor)
Inability to communicate with the steering column module via a scan tool or intermittent communication
Vehicle may go into limp mode or refuse to allow steering lock to release on some vehicles
Random or persistent related DTCs in other modules (communication faults)

What to check

Read and record all stored codes and freeze-frame data from all modules
Confirm inability to communicate with the steering column module using a diagnostic scanner
Inspect battery voltage at rest and with ignition on (11–15 V expected)
Check fuses and relays supplying the steering column module and associated circuits
Visually inspect the module connector and wiring for corrosion, bent pins, moisture, chafing or damage
Verify good ground(s) at the module (measure continuity to chassis) and check for high-resistance grounds

Signal parameters

Module supply voltage (key ON): ~11–15 V (nominal battery/ignition feed)
Module ground: low resistance to chassis (typically
CAN bus idle voltages: CAN_H ~2.5–3.5 V, CAN_L ~1.5 V (differential ~0 V idle but common-mode ~2.5 V) — verify bus is within manufacturer spec
Communication: module should respond to diagnostic requests on CAN/LIN (if present)
Wake/sleep current: module should not draw excessive current in sleep (check manufacturer spec)
Steering angle sensor output (if integrated): should produce valid angle values and not be erratic

Diagnostic algorithm

Safely record vehicle state and all related DTCs from all modules; do not clear codes yet. 2) Attempt to communicate with the steering column module with a capable scan tool; note connection status and any live data. 3) Verify battery voltage and main power/ignition feed to the module; inspect and test relevant fuses and relays. 4) Inspect connector and wiring at module for corrosion, moisture, damage and correct pin seating; repair as needed. 5) Measure continuity/voltage at module power and ground pins; repair high resistance or open circuits. 6) Check CAN/LIN bus integrity: measure idle voltages, check termination resistor(s), and look for shorts to power or ground. 7) Perform wiggle/stress tests on harness and connectors while monitoring communications and bus signals. 8) If wiring and supplies are good, check for available software/firmware updates or reflash procedures; follow manufacturer reflash/relearn steps if supported. 9) If module still reports internal fault after software update and all inputs/power/communications are confirmed good, consider replacing the steering column control module. 10) After repair or replacement, program or configure the new module per manufacturer procedure, clear codes, and verify proper operation and that related systems (steering angle, stability control) show no faults.
similar_codes([
U0100
U0073
B13C8
B13C0
B13D0
B1A00
U0121
P0643
B2799

Likely causes

Module internal electronics or firmware fault
Power or ground fault at the module (blown fuse, bad ignition feed, poor ground)
Connector corrosion, bent pins, or water ingress at the module connector
CAN bus communication error preventing normal module operation

Fault status

⚠️ Status

Steering column control module internal fault detected. Module self-test has failed or internal error/communication fault present. May require wiring repair, software update, or module replacement and programming.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0 - 3.0 hours