Lost Communication With Battery Pre-Charge Module
The U0270 code means the vehicle's onboard diagnostic system has detected: Lost Communication With Battery Pre-Charge Module. This is a critical severity code.
- Keep driving?
- No -- stop driving
- DIY difficulty
- hard
- Estimated cost
- $400 - $2,000 (parts and labor)
Network codes mean modules are not communicating. You need a scanner that reads all systems to find the problem.
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Common Symptoms
- Vehicle will not power up HV system
- Contactor relay clicking but not engaging
- High-voltage system fault warning
- Pre-charge timeout error
- Cannot enter ready mode
Probable Causes (Ranked by Likelihood)
- Failed pre-charge resistor or relay Very High
- Battery contactor failure High
- CAN bus wiring fault to pre-charge module Moderate
- High-voltage capacitor fault Low
Step-by-Step Diagnostic Procedure
-
Check battery contactor relay operation
-
Scan pre-charge module for codes
-
Test pre-charge resistor continuity
-
Verify HV capacitor bank condition
Frequently Asked Questions
Can I drive with U0270?
No. The pre-charge circuit is essential for safely energizing the high-voltage system.
What causes U0270?
Usually a failed pre-charge resistor or battery contactor relay.
What is pre-charge?
It gradually applies voltage to the system to prevent damaging inrush current.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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