What does code U3533 mean?

Q: What does code U3533 mean?

High Voltage System Interlock Circuit K Low. The high-voltage interlock loop is a safety circuit that confirms all high-voltage connectors, covers, and service disconnects are properly seated before the battery pack energizes. Code U3533 sets when the control module monitoring circuit K detects a voltage level that is too high, indicating an open or high-resistance path rather than a short to ground. The vehicle may disable the high-voltage system entirely, preventing the engine from starting or the traction battery from engaging.

DTC codes / U35xx · Network communication / U3533

U3533High Voltage System Interlock Circuit K Low

The high-voltage interlock loop is a safety circuit that confirms all high-voltage connectors, covers, and service disconnects are properly seated before the battery pack energizes. Code U3533 sets when the control module monitoring circuit K detects a voltage level that is too high, indicating an open or high-resistance path rather than a short to ground. The vehicle may disable the high-voltage system entirely, preventing the engine from starting or the traction battery from engaging.

SystemNetwork

Code typeGeneric (all makes)

SeverityHigh

Fix difficultyProfessional

AreaNetwork communication

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.