What are the common causes of U3512?

Interlock loop B voltage outside its expected range. High resistance in the interlock loop B wiring. A loose or corroded interlock loop B connector. Water in the interlock loop B connector.

Read high voltage interlock circuit B status on a scan tool. De-energize the high voltage system before touching any connector. Inspect interlock loop B connector pins for corrosion and water. Test interlock loop B for continuity and resistance. Repair interlock loop B wiring if the signal stays out of range. Clear the code and retest.

U3512

High Voltage System Interlock Circuit B Performance

System: Network communication (U code)
Lamp: Check Engine Light
Category: Network Communications

What it means

U3512 means High Voltage System Interlock Circuit B Performance.

Check these first

Interlock loop B voltage outside its expected range
High resistance in the interlock loop B wiring
A loose or corroded interlock loop B connector
Water in the interlock loop B connector

What to do next

Read high voltage interlock circuit B status on a scan tool
De-energize the high voltage system before touching any connector
Inspect interlock loop B connector pins for corrosion and water
Test interlock loop B for continuity and resistance
Repair interlock loop B wiring if the signal stays out of range
Clear the code and retest

Look up another code

Code or symptom

Enter a full code or a symptom. Press / to search. How to read a code

Type a code above, or start from a symptom or a common code.

Updated

Generic SAE J2012 definition. Last updated 2026-10-10.