OBD-II code · Network (extended)
U3027 Control Module A Disable Circuit High
Disable line A 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.
Is it safe to drive with U3027?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyWiring shorted to battery
- Less likelyGateway module routing CAN messages incorrectly
- Less likelyCAN 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
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–2 h
- Emissions test
- Usually unaffected
- Parts involved
- Module Disable A, Control Wiring
Related codes
- U3024Control Module Input Power Circuit B - Ignition Input On/Start Circuit Correlation
- U3025Control Module A Disable Circuit/Open
- U3026Control Module A Disable Circuit Low
- U3028Control Module A Disable Feedback Circuit
- U3029Control Module A Disable Feedback Circuit Low
- U302AControl Module A Disable Feedback Circuit High
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.