AutoCodes – Generic – P0439

P0439 Code - Catalyst Heater Control Circuit Bank 2

Quick Answer

The Engine Control Module (ECM) monitors the Catalyst Temperature Sensor Circuit Performance, which measures the temperature of the catalyst. Common causes include Faulty Catalyst Temperature Sensor, Catalyst Temperature Sensor harness is open or shorted, Catalyst Temperature Sensor circuit poor electrical connection. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means: P0439 indicates Catalyst Heater Control Circuit Bank 2.
Common causes: Common causes include Faulty Catalyst Temperature Sensor, Catalyst Temperature Sensor harness is open or shorted, Catalyst Temperature Sensor circuit poor electrical connection.
Severity: Moderate - service should be scheduled soon.
Can I drive?: The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 11,423

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Apr 18, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P0439 Description

The Engine Control Module (ECM) monitors the Catalyst Temperature Sensor Circuit Performance, which measures the temperature of the catalyst. Catalyst Temperature Sensor function by increasing their resistance with increasing exhaust gas temperature. The ECM sets the OBDII code when the Catalyst Temperature Sensor signal is not to factory specifications.

OBDII Code P0439 - Catalyst Heater Control Circuit Bank 2 - AutoCodes.com — P0439 Code - Catalyst Heater Control Circuit Bank 2

What does this mean?

What are the Possible Causes of the DTC P0439?

Faulty Catalyst Temperature Sensor
Catalyst Temperature Sensor harness is open or shorted
Catalyst Temperature Sensor circuit poor electrical connection

How to Fix the DTC P0439?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0439 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0439 code?

Need more information on how to fix the P0439 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0439 code diagnosed by a professional: Find a repair shop in your area

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.