OBD Guide

U040A

Invalid Data Received From Air Conditioning Control Module

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

Symptoms

  • Incorrect operation of the air conditioning system
  • No cold air from vents
  • Spontaneous turning on/off of the air conditioner
  • Error message on the dashboard
  • Some climate control functions do not work

Causes

  • Air conditioning control module malfunction
  • Problems with wiring to the air conditioning module
  • Corrosion or poor contact in connectors
  • Problems with power supply to the air conditioner module
  • Interference on the CAN bus

How to Fix

  1. Check the power and ground of the air conditioner module
  2. Inspect connectors and wiring for damage
  3. Scan the air conditioner module for errors
  4. Check the quality of communication via the CAN bus
  5. If necessary, replace the air conditioning control module

Related codes

Error U040A by Vehicle Brand