AutoCodes – Generic – P0424

P0424 Code - Heated Catalyst Temperature Below Threshold Bank 1

Quick Answer

The Engine Control Module (ECM) monitors the switching frequency ratio of heated oxygen sensors 1 (front O2 sensor) and heated oxygen sensors 2 (rear O2 sensor). Common causes include Air leak before catalytic converter, Faulty oxygen sensor, Faulty Catalytic Converter. 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: P0424 indicates Heated Catalyst Temperature Below Threshold Bank 1.
Common causes: Common causes include Air leak before catalytic converter, Faulty oxygen sensor, Faulty Catalytic Converter.
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.

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Code Popularity 20,004

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 Aug 20, 2020

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
Comments
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Code P0424 Description

The Engine Control Module (ECM) monitors the switching frequency ratio of heated oxygen sensors 1 (front O2 sensor) and heated oxygen sensors 2 (rear O2 sensor).
A three way catalyst converter (Manifold) with high oxygen storage capacity will indicate a low switching frequency of heated oxygen sensor 2. As oxygen storage capacity decreases, the heated oxygen sensor 2 switching frequency will increase.
When the frequency ratio of heated oxygen sensors 1 and 2 approaches a specified limit value, the three way catalyst malfunction is diagnosed.

OBDII Code P0424 - Heated Catalyst Temperature Below Threshold Bank 1 - AutoCodes.com — P0424 Code - Heated Catalyst Temperature Below Threshold Bank 1

What does this mean?

What are the Possible Causes of the DTC P0424?

Air leak before catalytic converter
Faulty oxygen sensor
Faulty Catalytic Converter

How to Fix the DTC P0424?

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 does this mean?

Code Tech Notes

As the code description implies the P0424 code means that the vehicle's control module has detected that the three-way catalytic converter is not working properly (is not as efficient as the factory is expecting). Replacing the oxygen (O2) sensors may sometimes fix the code, but in most cases the catalytic convert needs to be replaced to fix the problem. If the P0424 code is combined with other codes, try fixing the other codes first.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0424 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 P0424 code?

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Need Help with the Code?

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Information for Specific Makes

P0424 Audi — Heated Catalyst Temperature Below Threshold Bank 1
P0424 Mercedes-Benz — Heated Catalyst Temperature Below Threshold Bank 1
P0424 Volkswagen — Heated Catalyst Temperature Below Threshold Bank 1

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.