OBD Guide

P1798

Coolant Temperature Circuit Malfunction

P1798 is an OBD-II diagnostic trouble code meaning: Coolant Temperature Circuit Malfunction. Common causes: coolant temperature sensor malfunction, open or short circuit in the sensor circuit. Estimated repair cost: $6–28.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$6–28 (est.)

Symptoms

  • Unstable engine operation
  • Increased fuel consumption
  • Engine overheating
  • Check Engine Light Is On
  • Incorrect temperature readings on the dashboard

Causes

  • Coolant temperature sensor malfunction
  • Open or short circuit in the sensor circuit
  • Poor contact in the sensor connector
  • Wiring harness damage
  • ECU malfunction

How to Fix

  1. Check the continuity of the coolant temperature sensor circuit
  2. Check the sensor connector for oxidation or damage.
  3. Replace the coolant temperature sensor if necessary
  4. Check and replace wiring harness if necessary
  5. Check the operation of the computer

Related codes

Error P1798 by Vehicle Brand

FAQ

What does the P1798 code mean?

P1798 is an OBD-II diagnostic trouble code that indicates: Coolant Temperature Circuit Malfunction

What causes a P1798 error code?

The most common causes of P1798 include: Coolant temperature sensor malfunction; Open or short circuit in the sensor circuit; Poor contact in the sensor connector; Wiring harness damage.

How do I fix a P1798 diagnostic trouble code?

To fix P1798: Check the continuity of the coolant temperature sensor circuit. Check the sensor connector for oxidation or damage.. Replace the coolant temperature sensor if necessary. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P1798?

Limited driving only, diagnose soon

How much does it cost to fix P1798?

The estimated repair cost for P1798 is $6–28. Actual cost depends on your vehicle, location, and labor rates.

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