Network, generic (extended)

U352B High Voltage System Interlock Circuit H Low

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

U352B reports too low a level on interlock loop H. Apart from a pulled plug or a grounded wire, a deliberate opening can cause it: Texas Instruments mentions feeding a crash signal into the loop so that high voltage shuts off after an accident. The DGUV warns that such a crash shutdown does not establish absence of voltage and that disconnection following the maker's rescue sheet is still advisable; FMVSS 305a takes its post-crash voltage readings in a window from 10 s to one minute after the impact. No maker documents U352B. After a collision, replace damaged loop sections rather than patching them, and have trained staff isolate the system.

Likely causes

Loop H opened on purpose by a crash signal after an accident
Loop H wiring or plug damaged in a collision
Loop H wire shorted to ground

Symptoms

  • High voltage off after an accident or airbag deployment
  • Vehicle cannot be made ready

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–2,500
Time1–6 h

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

Parts involved

hvil loop hhvil wiring

Related codes

U3529U352AU352CU3527P0A0C

References: ti.com, dguv.de, law.cornell.edu.