The CAN-Low signal is held above its valid range, typically because of a short to battery voltage on the CAN-L wire. Bus communication is lost for every node sharing this segment.
Medium severity. Can I keep driving?It depends on which control module has dropped out. If it affects the engine, brakes, or steering, do not continue your trip: call for roadside assistance.
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Most likely causes
- CAN-Low shorted to battery voltage
- Chafed harness against power wire
- Gateway module routing CAN messages incorrectly
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: hard
- It can trigger limp mode.
What each character of U0008 means
- U: Communication network
- 0: Generic code: same on every make
- 0: Subsystem depends on the code range
- 08: Specific fault in that system
Frequently asked questions
Can I keep driving with code U0008?
It depends on which control module has dropped out. If it affects the engine, brakes, or steering, do not continue your trip: call for roadside assistance.
What causes code U0008?
The most common causes are: cAN-Low shorted to battery voltage; chafed harness against power wire; gateway module routing CAN messages incorrectly.
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.