What C8 means
The detergent cup is being blocked from opening fully.
Likely causes
- Silverware, a pan or a tall item blocking the cup
Safe first checks
- Remove whatever is blocking the cup.
- Close and latch the door and wait 30 seconds for the cup to open.
When to stop
If the cup still won't open with nothing blocking it, schedule service.
Checked against: GE Appliances: Dishwasher - Error, Fault or Function Codes. Codes can differ by model and year, so confirm with your owner's manual.