OBD Guide

U0633

Lost Communication With Fan 2

U0633 is an OBD-II diagnostic trouble code meaning: Lost Communication With Fan 2. Common causes: open or short circuit in wiring, fan relay fault. Estimated repair cost: $17–89.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$17–89 (est.)

Symptoms

  • Engine overheating
  • The second cooling fan does not work
  • Check Engine Light Is On
  • Reduced engine performance

Causes

  • Open or short circuit in wiring
  • Fan relay fault
  • Problems with the engine control unit
  • Malfunction of the fan itself

How to Fix

  1. Check the integrity of the wiring to the fan
  2. Check fan relay operation
  3. Check fan circuit fuses
  4. Check the operation of the fan
  5. Check control signals from ECU

Related codes

Error U0633 by Vehicle Brand

FAQ

What does the U0633 code mean?

U0633 is an OBD-II diagnostic trouble code that indicates: Lost Communication With Fan 2

What causes a U0633 error code?

The most common causes of U0633 include: Open or short circuit in wiring; Fan relay fault; Problems with the engine control unit; Malfunction of the fan itself.

How do I fix a U0633 diagnostic trouble code?

To fix U0633: Check the integrity of the wiring to the fan. Check fan relay operation. Check fan circuit fuses. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U0633?

Limited driving only, diagnose soon

How much does it cost to fix U0633?

The estimated repair cost for U0633 is $17–89. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat