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U351E High Voltage System Interlock Circuit E Performance

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

U351E points to loop E giving results the module cannot trust, and the doubt may concern the monitoring hardware as much as the wiring. Designers do test their own test circuits: CATL first checks its current-generating stage so that a failing source is not blamed on high-voltage parts, and Sanden's interlock at the plug of an electric A/C compressor also recognises defects of the monitoring device and its loop, not only an unplugged connector. A performance code on loop E can therefore come from a drifting source or detector. No maker publishes U351E. Once wiring and plugs test fine, suspect the controller running the loop.

Likely causes

Current or voltage source for loop E drifting in the controller
Loose contact in a loop E connector
Detection circuit or its reference faulty
Controller software with outdated plausibility limits

Symptoms

  • High-voltage shutdowns without a recognisable pattern
  • Fault returns although wiring and connectors test good
  • Possibly further self-test codes in the same controller

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–2,000
Time1–5 h

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

Parts involved

hvil loop e

Related codes

U351DU351FU3520U351AP0A0B

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