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Catalytic converters are one of the most significant emission add-ons ever installed on a vehicle. They reduce tailpipe emissions of carbon monoxide (CO) and hydrocarbons (HC).  However, they could develop issues over time. P0429 is one of the trouble codes related to a fault in the catalyst heater control circuit.

What Does the P0429 Code Mean?

Diagnostic trouble code (DTC) P0429 stands for “Catalyst Heater Control Circuit Bank 1.” The powertrain control module (PCM) sets it when it detects an issue with the catalytic converter’s heating element.

catalytic converter with issue in heating element
A catalytic converter uses a catalyst to create a chemical reaction that converts harmful exhaust emissions into less harmful substances.

A catalytic converter uses a catalyst to create a chemical reaction that converts harmful exhaust emissions into less harmful substances. These catalysts are usually made up of rhodium, palladium, or platinum. These elements plus the extreme heat of the engine exhaust make the conversion of harmful substances possible.

The PCM logs code P0429 when the exhaust oxygen concentration measured by the upstream and downstream oxygen (O2) sensors is comparable. It could also store the code if it detects an electrical issue with the heated catalyst control circuit.

Note: The definition of code P0429 might be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Common Causes of the P0429 Code?

What are the Common Symptoms of the P0429 Code?

How to Diagnose the P0429 Code

DTC P0429 is a generic trouble code, but that does not imply that it has a universal solution. The steps for diagnosing this trouble code might differ depending on the vehicle.

In most cases, you’ll need more than a scan tool to diagnose a P0429 code. You’ll need specific equipment as well as up-to-date technical information about your vehicle’s traction control system. So if you are unfamiliar with vehicle repair and diagnosis, it is best to leave it to a reputable mechanic.

How to Fix the P0429 Code

Attempting to resolve any trouble code can be difficult, and the P0429 code is no exception. If you don’t have the necessary DIY skills and automotive know-how, it’s best to leave the job to a mechanic. Otherwise, you might end up causing more problems with your traction system.

However,  if you’re an experienced automotive DIYer and you want to do the job yourself, we recommend looking for vehicle-specific information before starting. Guides like those from Chilton or an ALLDATA subscription are helpful.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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