Bus C high-side line open. Same diagnostic as U0039 on bus C. A communication loss with this module breaks any function relying on its data — diagnostic tools may show 'no response' and dependent modules can fall into limp mode.
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
- Wire broken
- Gateway module routing CAN messages incorrectly
- CAN terminating resistor (120 Ω) drifted out of spec
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 U0048 means
- U: Communication network
- 0: Generic code: same on every make
- 0: Subsystem depends on the code range
- 48: Specific fault in that system
Frequently asked questions
Can I keep driving with code U0048?
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 U0048?
The most common causes are: wire broken; gateway module routing CAN messages incorrectly; cAN terminating resistor (120 Ω) drifted out of spec.
Related codes
- U0042Vehicle Communication Bus B (-) Open
- U0050Vehicle Communication Bus C (+) High
- U0039Vehicle Communication Bus B (+) Open
- U0057Vehicle Communication Bus D (+) Open
- U0031Vehicle Communication Bus A (+) Low
- U0060Vehicle Communication Bus D (-) Open
- U0066Vehicle Communication Bus E (+) Open
- U0078Control Module Communication Bus F Off
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.