Network, generic (extended)

U3541 High Voltage System Interlock Circuit O

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

U3541 denotes trouble on interlock circuit O, the fourteenth loop. What happens next may depend on the operating state. Tesla's 2013 HVIL diagnostic guide for the Model S, published through NHTSA, splits the reaction: in the modes Standby, Support and Charge the battery management stores a fault and opens the contactors, or leaves them open if they already are, whereas in Drive it only raises a warning so that the car does not lose propulsion. A loop O fault that occurs on the move may thus first be noticed as a car that will not restart after parking. No maker documents U3541 or the parts of loop O.

Likely causes

Connector in loop O not fully latched
Loop O wiring damaged
Internal fault in an HV component on loop O

Symptoms

  • Warning while driving without loss of drive
  • No ready mode after the vehicle was switched off
  • Charging refused

Repair estimate

DifficultyHardWorkshop job
Parts and labour€60–1,500
Time0.5–4 h

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

Parts involved

hvil loop ohv connectors

Related codes

U3542U3543U3544U353DP0A0A

References: static.nhtsa.gov, law.cornell.edu.