What it means
The Body Control Module (BCM) sent a request to the engine ECU to illuminate the MIL — actual fault is in a body system; this is a forwarded request, not a powertrain fault.
At a glance
- Usually lights the check-engine light
How it works
The Body Control Module (BCM) manages body and chassis features and can ask the engine ECU to switch on the malfunction indicator lamp (MIL). This code records that request; it does not identify an engine fault, so the BCM’s own codes and any body-system warning messages point toward the underlying problem.
Common causes
Most likely first.
- BCM-detected fault in a body or chassis system
- Wiring or connector fault affecting a body system
- BCM or related module fault
Symptoms
- Check-engine light on
- A body-system warning light or message may appear
- A body feature may malfunction, depending on the underlying fault
How to diagnose it
- Scan all available modules for BCM and chassis codes, and note any body-system warning messages that identify what prompted the MIL request.
- Use freeze-frame or event data, if available, to record when the BCM made the request and what vehicle conditions were present.
- Check the body feature or system named by the BCM codes, such as its fuse, connector, wiring, and operation.
- Inspect related harnesses and connectors for looseness, corrosion, water intrusion, or damage that could disrupt the affected body circuit.
- Test the affected circuit and its grounds against the manufacturer's specification before considering a BCM or related module fault.
- After repairing the underlying body-system fault, clear the codes and confirm the BCM no longer requests MIL illumination.
Common fixes
- Repair a loose, corroded, or damaged connector or wire in the body system identified by BCM codes.
- Replace a failed fuse or repair the short or open circuit that caused it to fail.
- Repair or replace the faulty body-system component identified by testing.
- Repair a faulty ground or power connection to the affected module.
- Replace or reprogram the BCM or related module only after its circuits and connected components test correctly.
Can I keep driving?
The request alone does not indicate an engine problem, but the underlying body fault may affect an important feature such as lighting or restraint equipment. Check any accompanying warning and avoid driving if a safety-related system is impaired.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.