U3511
High Voltage System Interlock Circuit B
Generic fault on the second high-voltage interlock loop (HVIL) circuit. The interlock detects whether HV connectors are properly mated; an open loop forces the HV system into a safe state.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: hard
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
Common causes
Ordered by how often each turns out to be the cause.
- HV connector not fully matedCommon
- Interlock pilot pin damagedPossible
- Gateway module routing CAN messages incorrectlyLess likely
Parts involved
- Hvil Loop B
- Hv Connectors
U3511 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.