OBD-II code · Chassis
C0727 Trailer Connector Circuit Malfunction
The chassis or trailer brake module has detected a fault in the trailer wiring connector — for example open lighting circuit or short to ground. Trailer brake and lighting functions may be unavailable.
Is it safe to drive with C0727?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyConnector pins corroded or bent
- PossibleShort or open in trailer wiring
Symptoms
- ABS warning light on
- ESC/stability control deactivated
- Possible reduced brake assist
- Speedometer may behave erratically
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.3–1.5 h
- Emissions test
- Usually unaffected
- Parts involved
- Trailer Connector, Trailer Wiring, Trailer Brake Module
Related codes
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.