Applicable Systems
OBD-II
Symptoms
Multiple chassis warning lights illuminate. Communication between chassis modules is disrupted. DTC C0978 is stored in the chassis control module.
Possible Causes
- CAN bus termination resistor open
- CAN high or low line shorted to ground
- Chassis CAN gateway fault
- Corroded CAN connector in chassis harness
Troubleshooting Steps
- Step 1: Connect a diagnostic scanner and read chassis DTCs to confirm C0978
DTC C0978 is present with freeze frame data showing conditions when it set - Step 2: Inspect wiring and connectors in the affected circuit for corrosion, damage, or loose pins
Wiring intact, connectors clean and properly seated - Step 3: Perform component-level testing per manufacturer diagnostic procedure for the specific subsystem
Component values within specification or component confirmed faulty - Step 4: Clear the DTC and verify it does not return after a road test
DTC does not return; system warning light stays off
How to Reset
Clear the DTC after repair using a diagnostic scanner. The code will clear automatically if the fault is no longer detected after 3 consecutive drive cycles.
Frequently Asked Questions
- Q: What does code C0978 mean?
This is a chassis-related diagnostic trouble code indicating an issue with the chassis can system. The specific subsystem should be diagnosed using the manufacturer's diagnostic procedure.
- Q: Can I drive with code C0978?
Limited driving is possible, but the affected chassis system may not function correctly. Have the vehicle diagnosed promptly to ensure safety systems like ABS and stability control are operational.
Source: SAE J2012 Standard OBD-II Diagnostic Trouble Codes
Category: OBD-II