U0112 Lost Communication with Battery Energy Control Module B
Diagnostic trouble code U0112 indicates a loss of communication between the powertrain control module (PCM) and the Battery Energy Control Module B. This occurs when the PCM stops receiving signals or data from this specific module over the controller area network (CAN bus). The lack of communication prevents proper monitoring and control of the vehicle's energy and charging systems. This code specifically refers to the loss of signal with the secondary 'B' module, distinguishing it from other energy modules on the network.
1. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.
2. Most Common Causes
- Faulty or damaged Battery Energy Control Module B
- Open or shorted CAN bus wiring
- Corroded, bent, or damaged pins in the module B connector
- Blown fuses or relays supplying power to the energy module
- Poor ground connection or loss of voltage supply to the module
- Faulty PCM or network gateway
3. Symptoms You Will Notice
- Check Engine Light illuminated
- Battery or charging system warning light on
- Erratic battery charging behavior
- Reduced fuel economy or performance
- Vehicle may not start or have electrical issues
4. Step-by-Step Diagnosis
Scan for additional codes and verify U0112 is present
Inspect CAN bus wiring and connectors for damage, corrosion, or loose connections
Check fuses and relays related to the Battery Energy Control Module B
Test voltage and ground at the module B connector
If wiring and power are OK, suspect a faulty module B or PCM
5. Frequently Asked Questions
Is it safe to drive?▼
No, driving with this code is not recommended as it can lead to battery charging issues, potential stalling, or electrical system failure. Have the vehicle diagnosed and repaired promptly.
How much does it cost to fix?▼
Repair costs vary widely depending on the root cause. Diagnosing the issue typically costs $100-$200. Replacing a module can range from $300 to $800, while wiring repairs may be $150-$400.