Network, generic (extended)

U352F High Voltage System Interlock Circuit J Low

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

U352F means loop J reads below its lower threshold, the picture an interrupted loop gives. In high-voltage plugs the interlock pins are shorter than the power pins, so they part first when the plug is withdrawn. A TE Connectivity product manager puts the resulting lead at just one to three milliseconds for a plug pulled quickly, while switching the whole system off can take close to a second, and adds that a closed loop does not prove full mating. A Hyundai and Kia connector patent names the same weakness of fast separation. A plug in loop J that has been pulled back slightly, or a dropped interlock pin, is thus the first suspect. No maker lists U352F; the contactors stay open.

Likely causes

High-voltage plug in loop J partly withdrawn, interlock pins already apart
Interlock pin in loop J pushed back in its cavity
Loop J wire chafed through to ground

Symptoms

  • High-voltage system switches off and stays off
  • No ready mode after work near high-voltage plugs
  • Charging not possible

Repair estimate

DifficultyHardWorkshop job
Parts and labour€60–1,200
Time0.5–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

hvil loop jhvil wiring

Related codes

U352DU352EU3530U352BP0A0C

References: connectorsupplier.com, patents.google.com, law.cornell.edu.