U352D: High Voltage System Interlock Circuit J

What does U352D mean?

Generic fault on HVIL loop J. Note - SAE skips letter "I" to avoid confusion with the digit 1. The interlock is a low-voltage signal loop routed through the HV connectors and covers; the monitoring module drives a current or signal through it and opens the HV contactors, or refuses to close them, when the loop is broken or out of range, so that no HV connection can be opened while live.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Vehicle will not switch to ready mode or the HV system shuts down
• High-voltage system warning in the instrument cluster
• Charging may be blocked

Common causes

• High HV connector not fully mated
• Medium Damaged interlock wiring or corroded terminal in the loop
• Low Fault in the module that drives and evaluates the interlock loop

Likelihood is a general estimate across vehicles; your make and model may differ.