OBD2 Code U3007: Control Module B Input Circuit
The U3007 code is a generic network communication code indicating a problem with the B input power circuit of a control module. Per SAE J2012, U3xxx codes are manufacturer-specific network codes, but this one specifically refers to a power supply failure in a particular module. The 'B' designation typically denotes a secondary or backup power circuit, which may be a constant power source or a separate power line for critical module functions. When this code sets, the control module has detected a voltage outside the expected range on its B power input.
1. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.
2. Most Common Causes
- Blown or open fuse in the B power circuit
- Faulty power relay
- Short or open circuit in the power wiring
- Corroded or damaged connector
- Internal control module failure
- Charging system issue (battery or alternator)
3. Symptoms You Will Notice
- Check Engine Light illuminated
- Module may not function or operate intermittently
4. Step-by-Step Diagnosis
Scan for additional codes and note freeze frame data
Inspect fuses and relays related to the B power circuit
Check wiring and connectors for damage, corrosion, or loose connections
Test voltage at the module's B input pin with a multimeter
If voltage is correct, suspect internal module failure
5. Frequently Asked Questions
Is it safe to drive?▼
It is not recommended to drive with this code active, as it can cause critical module failures and potentially leave you stranded. Have the vehicle diagnosed and repaired promptly.
How much does it cost to fix?▼
Repair costs vary widely depending on the cause. Simple fuse or relay replacement may cost $50-$150, while wiring repairs or module replacement can range from $200 to $1,000 or more.