OBD-II code · Network (extended)
U3523 High Voltage System Interlock Circuit F Low
HVIL loop F voltage below 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 U3523?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyInterlock wire shorted to ground
- 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 F, Hvil Wiring
Related codes
- U3513High Voltage System Interlock Circuit B Low
- U3517High Voltage System Interlock Circuit C Low
- U351BHigh Voltage System Interlock Circuit D Low
- U351FHigh Voltage System Interlock Circuit E Low
- U3527High Voltage System Interlock Circuit G Low
- U352BHigh Voltage System Interlock Circuit H Low
- U352FHigh Voltage System Interlock Circuit J Low
- U3533High Voltage System Interlock Circuit K Low
- U3537High Voltage System Interlock Circuit L Low
- U353BHigh Voltage System Interlock Circuit M Low
- U353FHigh Voltage System Interlock Circuit N Low
- U3543High Voltage System Interlock Circuit O Low
- U3520High Voltage System Interlock Circuit E High
- U3521High Voltage System Interlock Circuit F
- U3522High Voltage System Interlock Circuit F Performance
- U3524High Voltage System Interlock Circuit F High
- U3525High Voltage System Interlock Circuit G
- U3526High Voltage System Interlock Circuit G Performance
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.