U0216 critical

Lost Communication With EV Battery Thermal Management Module

The U0216 code means the vehicle's onboard diagnostic system has detected: Lost Communication With EV Battery Thermal Management Module. This is a critical severity code.

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Keep driving?
No -- stop driving
DIY difficulty
hard
Estimated cost
$600 - $3,000 (parts and labor)
Diagnose CAN Bus Issues
LAUNCH CRP123X Full System Scanner

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

  • Battery overheating warning
  • Charging speed severely limited
  • Reduced power and range
  • Battery cooling system fault
  • Vehicle may enter turtle mode

Probable Causes (Ranked by Likelihood)

  • Failed battery thermal management module Very High
  • Coolant leak in battery cooling loop High
  • CAN bus wiring fault to thermal module Moderate
  • Thermal management pump failure Low

Step-by-Step Diagnostic Procedure

  1. Check battery coolant level and condition

  2. Inspect thermal management system for leaks

  3. Scan battery thermal module for fault codes

  4. Test CAN communication at thermal management module

Frequently Asked Questions

Can I drive with U0216?

No. Without thermal management the battery can overheat and suffer permanent damage.

What causes U0216?

Usually a failed thermal management module or coolant leak.

Is U0216 an emergency?

Yes. Battery overheating can be dangerous. Stop driving and have the vehicle towed.

Sources

This page is built from documented references. Verify against your own service info before repair work.

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