What it means
Input power line C voltage above expected range. 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.
At a glance
- Usually lights the warning light of the system that lost communication
- The engine or gearbox may go into limp mode
How it works
The module monitors its C input-power feed for voltage above the permitted range. This code sets when that feed is too high, which can disrupt the module or its messages to other modules.
Common causes
Most likely first.
- Alternator regulator failed
- Gateway module routing CAN messages incorrectly
- CAN terminating resistor (120 Ω) drifted out of spec
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
How to diagnose it
- Record freeze-frame data and scan all modules for overvoltage and communication codes to check whether the fault is widespread.
- Check battery condition and charging-system output, since a faulty alternator regulator can produce excessive voltage.
- Inspect the module’s C-feed connector, wiring, fuse, and ground for heat damage, poor contact, or signs of prior repair.
- Measure voltage at the C feed and compare it with the manufacturer's specification while the fault is active if possible.
- If charging voltage and C-feed supply are normal, check gateway routing and CAN wiring and termination using the vehicle wiring diagram.
Common fixes
- Clean and secure a poor C-feed or ground connection.
- Repair damaged C-feed wiring or replace a faulty connector terminal.
- Repair or replace a confirmed faulty alternator regulator.
- Repair a confirmed gateway or CAN network fault if C-feed voltage is correct.
Can I keep driving?
If several systems warn, shut down, or enter limp mode, stop safely because overvoltage can damage electronics and reduce vehicle function. If no symptoms are present, limit driving to a short trip for diagnosis and stop if electrical or drivability issues appear.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.