P0403 Code: Exhaust Gas Recirculation “A” Control Circuit Malfunction

The exhaust gas recirculation (EGR) system helps minimize nitrogen oxide gases coming from your vehicle’s exhaust. This is important because nitrogen oxide gases are very harmful for the environment in significant amounts.

When your vehicle’s powertrain control module (PCM) detects a fault in your EGR system, the P0403 code could be set.

NOTE: An understanding of the EGR system could help you address P0403 better. Here’s a primer.

What Does the P0403 Code Mean?

Diagnostic trouble code (DTC) P0403 stands for “Exhaust Gas Recirculation “A” Control Circuit.”

On GM vehicles (such as a 2016 Silverado), the P0403 code is stored when:

• The ECM/PCM detects an open circuit condition of an EGR motor control circuit for greater than 3 seconds.

OR

• The ECM/PCM detects an over temperature condition of the EGR control circuit internal to the ECM for greater than 3 seconds.

Note: The definition of code P0403 may be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Possible Causes of the P0403 Code?

Since OBD-II code P0403 is a generic code, it is supported by various makes and models. However, the diagnostics and repair procedures for it may vary depending on your vehicle’s year, make, and mode. Here are the common triggers of the P0403 code:

• Faulty EGR valve
• Carbon build-up in the EGR passages (only if the carbon buildup causes the pintle to stick).
• EGR control circuit issues, such as damaged wires or poor connections
• An issue with the PCM

What are the Common Symptoms of the P0403 Code?

The error code P0403 usually has no other noticeable symptoms except:

• Illuminated check engine light (most common)
• Instability when idle (only when the EGR valve is stuck open)
• Engine misfires (very, very rare)
• Stalling (only if the EGR valve is stuck open)
• Spark knock

In some cases, the P0403 code does not exhibit any noticeable warning signs.

How to Diagnose the P0403 Code

Again, diagnostic and repair steps for the P0403 code may vary depending on your car’s year, make, and model. For example, repair steps for P0403 in Ford may differ from the repair steps for a P0403 error code in a Chevy.

If you plan to fix the code yourself, below is a video you can watch to help you get an idea of what diagnosing it might involve. However, if you lack the DIY skill and experience, it is best to leave the job to professionals. They would know how to diagnose the problem and rule out any other underlying triggers.

How to Fix the P0403 Code

Due to the various issues that can trigger the P0403 code, it can be tricky to resolve it. Leave the task to your mechanic if you are not confident with your automotive knowledge and DIY skills.

Diagnosis is the first step of this engine code’s troubleshooting process. Once you’ve determined the exact cause of the issue, use online auto repair resources and guides to figure out the right way to fix the P0403 code. Then, check your owner’s manual to make sure the solution you found is appropriate for your vehicle.

Want to supplement your task with in-depth and up-to-date factory repair information? Consider securing an ALLDATA single-vehicle subscription. It will help you fix not only the P0403 code but also any other future issue your vehicle may encounter.

Find an EGR Valve That Fits Your Vehicle

When you drive without a working EGR valve, you increase the risk that the engine might develop additional issues that require costly repairs. Instead of ignoring the problem, you must replace the faulty part as early as possible. Good thing you can easily find a compatible EGR valve here at CarParts.com.

At CarParts.com, we make it convenient for you to find EGR valves and other automotive parts and accessories. Plug your car’s details into our website’s built-in vehicle selector, and you’ll see our products that meet your requirements. Ordering a new part takes only several taps on your phone, and our nearest distribution center will quickly process your order and ship your part. If you live in the continental US and order before 12 p.m. ET, your new EGR valve can arrive in several business days. Our knowledgeable customer service team is also here 24/7 to answer any questions about our products, such as price tag and fitment.

Make CarParts.com your one-stop shop for an EGR valve that fits your budget and vehicle. Check out our selection of EGR valves and find the one that’s best suited for your vehicle.

Products Mentioned in this Guide

EGR Valve EGR Vacuum Solenoid