OBD Guide

U0645

Lost Communication With Active Air Dam Module

U0645 is an OBD-II diagnostic trouble code meaning: Lost Communication With Active Air Dam Module. Common causes: open or short circuit in the spoiler module circuit, active spoiler module malfunction. Estimated repair cost: $56–278.

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

Symptoms

  • Active spoiler does not work
  • Check Engine light comes on
  • Possible error messages on the dashboard
  • Reduced aerodynamic performance at high speeds
  • The car may go into emergency mode

Causes

  • Open or short circuit in the spoiler module circuit
  • Active spoiler module malfunction
  • Problems with connectors or wiring harness
  • Failures in ECU software
  • Module power problems

How to Fix

  1. Check the integrity of the power supply and grounding circuits of the module
  2. Inspect connectors and wiring harness for damage
  3. Check the functionality of the active spoiler module
  4. Scan the system for other errors
  5. Update ECU software if necessary
  6. Repair only from an authorized dealer

Related codes

Error U0645 by Vehicle Brand

FAQ

What does the U0645 code mean?

U0645 is an OBD-II diagnostic trouble code that indicates: Lost Communication With Active Air Dam Module

What causes a U0645 error code?

The most common causes of U0645 include: Open or short circuit in the spoiler module circuit; Active spoiler module malfunction; Problems with connectors or wiring harness; Failures in ECU software.

How do I fix a U0645 diagnostic trouble code?

To fix U0645: Check the integrity of the power supply and grounding circuits of the module. Inspect connectors and wiring harness for damage. Check the functionality of the active spoiler module. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U0645?

Yes, but get it checked soon

How much does it cost to fix U0645?

The estimated repair cost for U0645 is $56–278. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat