OBD-II code · Network (extended)
U3512 High Voltage System Interlock Circuit B Performance
HVIL loop B is electrically OK but timing/pattern does not match expected behavior — possibly intermittent contact in a connector.
Is it safe to drive with U3512?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyIntermittent contact in HV connector
- 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
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–5 h
- Emissions test
- Usually unaffected
- Parts involved
- Hvil Loop B
Related codes
- U3516High Voltage System Interlock Circuit C Performance
- U351AHigh Voltage System Interlock Circuit D Performance
- U351EHigh Voltage System Interlock Circuit E Performance
- U3522High Voltage System Interlock Circuit F Performance
- U3526High Voltage System Interlock Circuit G Performance
- U352AHigh Voltage System Interlock Circuit H Performance
- U352EHigh Voltage System Interlock Circuit J Performance
- U3532High Voltage System Interlock Circuit K Performance
- U3536High Voltage System Interlock Circuit L Performance
- U353AHigh Voltage System Interlock Circuit M Performance
- U353EHigh Voltage System Interlock Circuit N Performance
- U3542High Voltage System Interlock Circuit O Performance
- U350FControl Module Cooling Fan Circuit Range/Performance
- U3510Control Module Missing Calibration
- U3511High Voltage System Interlock Circuit B
- U3513High Voltage System Interlock Circuit B Low
- U3514High Voltage System Interlock Circuit B High
- U3515High Voltage System Interlock Circuit C
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.