OBD Guide
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P1642

Fan Control Relay 2 and 3 Control Circuit

P1642 is an OBD-II diagnostic trouble code meaning: Fan Control Relay 2 and 3 Control Circuit. Common causes: open or short circuit in control circuit, fan relay fault. Estimated repair cost: $6–33.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$6–33 (est.)

Symptoms

  • Engine overheating
  • Cooling fans do not turn on or work incorrectly
  • The overheat warning light comes on
  • Reduced engine power
  • Possible transition to emergency mode

Causes

  • Open or short circuit in control circuit
  • Fan relay fault
  • Blown fuse
  • Wiring Harness Problems
  • Engine control unit malfunction

How to Fix

  1. Check the condition of the fuses
  2. Diagnose fan relay
  3. Check the integrity of the control circuit
  4. Inspect the wiring harness for damage
  5. If necessary, replace faulty components

Related codes

P1640P1641P1643

Error P1642 by Vehicle Brand

BuickCadillacChevroletFordGMGMCJaguarLincolnMercuryOldsmobileSaturnVolkswagen

FAQ

What does the P1642 code mean?

P1642 is an OBD-II diagnostic trouble code that indicates: Fan Control Relay 2 and 3 Control Circuit

What causes a P1642 error code?

The most common causes of P1642 include: Open or short circuit in control circuit; Fan relay fault; Blown fuse; Wiring Harness Problems.

How do I fix a P1642 diagnostic trouble code?

To fix P1642: Check the condition of the fuses. Diagnose fan relay. Check the integrity of the control circuit. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P1642?

Limited driving only, diagnose soon

How much does it cost to fix P1642?

The estimated repair cost for P1642 is $6–33. Actual cost depends on your vehicle, location, and labor rates.

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