CAN Bus Low Circuit Malfunction
The U0007 code indicates a communication fault on the high-speed Controller Area Network (CAN) bus, specifically affecting the CAN Low circuit. The CAN bus uses two wires (CAN High and CAN Low) to transmit differential data between electronic control modules. This code means the reporting module has detected an electrical or signal anomaly on the CAN Low line, preventing proper data transmission on the high-speed network.
1. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.
2. Most Common Causes
- Short to ground on the CAN Low wire
- Short to voltage on the CAN Low wire
- Open circuit in the CAN Low wire (cut or disconnected)
- Faulty CAN bus termination resistor (outside the nominal 60 ohms across the bus)
- Damaged, corroded, or bent pins in the CAN bus connector
- Faulty electronic control module causing an internal short on the network
3. Symptoms You Will Notice
- Check Engine Light or other warning lights illuminated
- Multiple electronic systems malfunctioning or inoperative (e.g., ABS, transmission, instrument cluster)
4. Step-by-Step Diagnosis
Scan all modules for related communication codes
Inspect CAN bus wiring and connectors for damage, corrosion, or loose connections
Measure resistance between CAN High and CAN Low at the OBD2 port (should be approximately 60 ohms)
Check for shorts to ground or voltage on the CAN Low wire using a multimeter
Isolate and test termination resistors if resistance is out of spec
If wiring and resistors are good, suspect a faulty module; disconnect modules one by one to isolate the issue
5. Frequently Asked Questions
Is it safe to drive?▼
No, it is not safe to drive. The U0007 code indicates a high-severity communication fault that can cause multiple critical systems (such as ABS, transmission, and engine management) to fail or behave unpredictably, increasing the risk of an accident.
How much does it cost to fix?▼
The cost varies widely depending on the root cause. Simple wiring repairs may cost $100-$300, while replacing a faulty control module can range from $500 to $1,500 or more, including diagnostics and labor.