U0223 moderate

Lost Communication With EV Auxiliary Power Module

The U0223 code means the vehicle's onboard diagnostic system has detected: Lost Communication With EV Auxiliary Power Module. This is a moderate severity code.

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Keep driving?
Short distances only
DIY difficulty
hard
Estimated cost
$300 - $1,200 (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

  • 12V accessories losing power intermittently
  • Infotainment system rebooting
  • Climate control shutting off
  • Headlights dimming
  • Auxiliary battery warning

Probable Causes (Ranked by Likelihood)

  • Failed auxiliary power module Very High
  • 12V auxiliary battery degradation High
  • CAN bus wiring fault Moderate
  • Power module overheating Low

Step-by-Step Diagnostic Procedure

  1. Test 12V auxiliary battery voltage and health

  2. Check auxiliary power module connections

  3. Scan auxiliary module for fault codes

  4. Inspect CAN bus wiring to auxiliary module

Frequently Asked Questions

Can I drive with U0223?

Only short distances. Accessories may lose power and the vehicle may not restart.

What causes U0223?

Most commonly a degraded 12V auxiliary battery or failed auxiliary power module.

How much does U0223 cost to fix?

Typically $300 to $1,200.

Sources

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

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