What it means
Battery Monitor Module Current Monitoring Performance: the component is electrically intact but its response does not match the command. The module reports battery current, voltage and temperature for charge management.
At a glance
- Usually lights the check-engine light
How it works
The battery monitor module uses a current sensor or shunt to measure current flowing into and out of the battery. This code sets when its current-monitoring response is outside expected performance, which can lead to incorrect charge-management decisions.
Common causes
Most likely first.
- Battery-monitor current sensor or shunt fault
- Loose, corroded, or damaged sensor connections
- Damaged wiring
- Battery-monitor module fault
Symptoms
- Battery or charging warning light may appear
- Start-stop system may be unavailable
- Charging behavior may change
How to diagnose it
- Record freeze-frame data and read battery current and charging-system data with a scan tool to establish when the fault occurs.
- Inspect the battery current sensor or shunt and its connections for looseness, corrosion, heat damage, or incorrect installation.
- Check the current-sensor wiring and connectors for breaks, chafing, pin damage, or poor contact.
- Compare scan-tool current readings with an appropriate independent current measurement under the manufacturer's test conditions.
- If the sensor circuit and connections pass, follow the manufacturer's procedure to assess the battery monitor module.
Common fixes
- Clean and secure the current sensor or shunt connections.
- Repair damaged current-sensor wiring or connector terminals.
- Replace a faulty battery current sensor or shunt.
- Replace the battery monitor module if it fails the specified current-monitoring checks.
Can I keep driving?
Driving may be possible, but charging behavior and start-stop operation can be affected if battery current is being misread. If the battery or charging warning appears, or the engine is difficult to start, limit driving and arrange a charging-system check.
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.