C0670

Code

Generic C — Chassis

Brake Control Module Internal Fault

Brand: Generic

Type: C — Chassis

Views: UK: 5 EN: 11 RU: 9

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Page language: EN

Causes

Internal electronic/component failure inside the brake control module
Corrupted module software or memory (firmware fault)
Intermittent or lost power/ground to the module
CAN/LIN network communication errors or short circuits
Water ingress, corrosion, or physical damage to the module or connector
Aftermarket modules/devices or improper modifications causing conflicts

Symptoms

ABS/traction control/wheel slip warning lamp illuminated
Brake system warning lamp or master warning on dash
Loss or intermittent operation of ABS, traction control, or stability systems
Inconsistent brake feel or unexpected braking intervention
Multiple related DTCs or communication faults present

What to check

Read all stored codes and freeze frame data from ABS/brake module and other modules
Verify vehicle battery voltage (engine off and cranking) and charging system condition
Inspect ABS module connector and wiring for corrosion, damage, pin push-back or water intrusion
Check fuses and relays for the ABS/brake module power circuits
Scan CAN bus for communication errors, bus-off conditions and look for missing nodes
Attempt a key-cycle and clear the code; check if the code returns immediately

Signal parameters

Module supply voltage: battery present ~12.0–14.5 V (engine running); significant drops or spikes indicate issue
Module ground: low resistance to chassis ground; measure voltage drop while cranking
CAN High/Low idle voltages: ~2.5 V each, differential ~0 V; dominant states should show expected differential (~1–2 V)
CAN bus error counters and message frequency for ABS node (use a capable scan tool or CAN scope)
Module wake/sleep line(s) state per manufacturer data
Module current draw (abnormal high draw may indicate internal failure)

Diagnostic algorithm

Record all codes and freeze frame data from ABS/brake module and any interrelated modules (engine, traction, gateway).
Visually inspect module and harness for water, corrosion, physical damage, and secure connector locking tangs; repair any damage.
Verify battery and charging system health; ensure battery charge is >=12.4 V and starter/crank conditions are normal.
Check fuses/relays for the ABS module power and ignition-switched supply; backprobe power/ground pins for stable voltage while cycling key.
Using a diagnostic tool, monitor CAN bus traffic. Confirm the ABS module is transmitting and receiving expected CAN frames; note communication faults.
Wiggle test wiring with the harness connected while monitoring live data and DTCs to look for intermittent faults.
If power/ground and CAN are good, attempt to clear codes and perform a hard reset (battery disconnect per manufacturer or scan-tool reset) to see if the fault is transient.
Check for available calibration/software updates or service bulletins. Reflash or reprogram the module only with the correct OEM procedure and tool if supported.
If code persists after verifying harness, power, and communication and reprogramming is not effective, consider module replacement. Verify part number and VIN-specific programming requirements before replacement.
After repair or replacement, clear codes and perform a road test and functional tests (ABS activation, traction control checks) to confirm fault does not return.

Likely causes

Faulty module hardware (processor, internal sensor, or I/O driver)
Poor battery voltage or intermittent 12V supply to module
Corroded, bent or loose connector pins at module harness
CAN bus short, high resistance, or missing termination affecting module
Failed internal non-volatile memory (EEPROM/flash) or corrupted calibration

Fault status

⚠️ Status

Brake control module internal fault detected. Module may be impaired or unable to perform normal ABS/stability functions. Investigation of power, ground, communications and module integrity required.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.5 hours