OBD Guide
ENFRDEESPT

U18A4

Lost Communication With Hybrid/EV Battery DC Charging Communications Gateway Module On High Voltage Energy Management CAN Bus

U18A4 is an OBD-II diagnostic trouble code meaning: Lost Communication With Hybrid/EV Battery DC Charging Communications Gateway Module On High Voltage Energy Management CAN Bus. Common causes: open or short circuit in the energy management can bus, malfunction of the high-voltage battery charging module. Estimated repair cost: $56–278.

Severity
🔴 High
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$56–278 (est.)

Symptoms

  • Malfunction warning on the dashboard
  • Inability to charge high voltage battery
  • Reduced power or transition to emergency mode
  • Disabling the hybrid system
  • Errors in other systems related to the high-voltage battery

Causes

  • Open or short circuit in the energy management CAN bus
  • Malfunction of the high-voltage battery charging module
  • Problems with power supply to the charging module
  • Corrosion or poor contact in connectors
  • Software error in the control system

How to Fix

  1. Check the integrity of the CAN bus and connections
  2. Check the power supply to the charging module
  3. Inspect connectors for corrosion or damage
  4. Try to reboot the system (disconnect and reconnect the 12V battery)
  5. Repair only from an authorized dealer

Related codes

U18A2U18A3U18A5

FAQ

What does the U18A4 code mean?

U18A4 is an OBD-II diagnostic trouble code that indicates: Lost Communication With Hybrid/EV Battery DC Charging Communications Gateway Module On High Voltage Energy Management CAN Bus

What causes a U18A4 error code?

The most common causes of U18A4 include: Open or short circuit in the energy management CAN bus; Malfunction of the high-voltage battery charging module; Problems with power supply to the charging module; Corrosion or poor contact in connectors.

How do I fix a U18A4 diagnostic trouble code?

To fix U18A4: Check the integrity of the CAN bus and connections. Check the power supply to the charging module. Inspect connectors for corrosion or damage. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U18A4?

Yes, but get it checked soon

How much does it cost to fix U18A4?

The estimated repair cost for U18A4 is $56–278. Actual cost depends on your vehicle, location, and labor rates.

FRDEESPT

See also: Russian version · NationStat