OBD Guide

U0409

Invalid Data Received From Alternative Fuel Control Module

U0409 is an OBD-II diagnostic trouble code meaning: Invalid Data Received From Alternative Fuel Control Module. Common causes: alternate fuel module malfunction, open or short circuit in the communication circuit. Estimated repair cost: $56–278.

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

Symptoms

  • Check Engine light comes on
  • Reduced engine power
  • The car switches to the main type of fuel
  • Increased fuel consumption
  • Unstable engine operation

Causes

  • Alternate fuel module malfunction
  • Open or short circuit in the communication circuit
  • Connector problems or contact corrosion
  • Software error in ECU
  • Module power problems

How to Fix

  1. Check the integrity of the wiring harness to the module
  2. Inspect and clean connector contacts
  3. Check the power supply and ground of the module
  4. Scan the module for additional error codes
  5. If necessary, replace the alternative fuel module

Related codes

Error U0409 by Vehicle Brand

FAQ

What does the U0409 code mean?

U0409 is an OBD-II diagnostic trouble code that indicates: Invalid Data Received From Alternative Fuel Control Module

What causes a U0409 error code?

The most common causes of U0409 include: Alternate fuel module malfunction; Open or short circuit in the communication circuit; Connector problems or contact corrosion; Software error in ECU.

How do I fix a U0409 diagnostic trouble code?

To fix U0409: Check the integrity of the wiring harness to the module. Inspect and clean connector contacts. Check the power supply and ground of the module. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U0409?

Yes, but get it checked soon

How much does it cost to fix U0409?

The estimated repair cost for U0409 is $56–278. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat