AutoCodes – Pontiac – P0403 Pontiac

P0403 Pontiac Code - Exhaust Gas Recirculation Control Circuit

Quick Answer

The Engine Control Module (ECM) supplies the Exhaust Gas Recirculation (EGR) valve with a 5 V reference circuit, a low reference circuit, an H-bridge motor directional control circuit, and a signal circuit. Common causes include Faulty Exhaust Gas Recirculation (EGR) Valve, Exhaust Gas Recirculation Valve harness is open or shorted, Exhaust Gas Recirculation Valve 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: P0403 Pontiac indicates Exhaust Gas Recirculation Control Circuit.
Common causes: Common causes include Faulty Exhaust Gas Recirculation (EGR) Valve, Exhaust Gas Recirculation Valve harness is open or shorted, Exhaust Gas Recirculation Valve 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.

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Code Popularity 7,557

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 Mar 24, 2024

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0403 Pontiac Description

The Engine Control Module (ECM) supplies the Exhaust Gas Recirculation (EGR) valve with a 5 V reference circuit, a low reference circuit, an H-bridge motor directional control circuit, and a signal circuit. The EGR position sensor provides a signal voltage that changes relative to the EGR position. The EGR position sensor information is transmitted between the EGR valve and the ECM on the signal circuit. The Mass Air Flow (MAF) sensor signal is used by the ECM to detect the proper amount of EGR flow. The ECM will close the EGR valve, then open the EGR valve to 100%. The ECM will then calculate the MAF difference and determine if the proper EGR flow has been detected. The Diagnostic Trouble Code (DTC) will be set when the ECM detects an open on the control circuit for greater than 2.5 s.

OBDII Code P0403 Pontiac - Exhaust Gas Recirculation Control Circuit - AutoCodes.com — P0403 Pontiac Code - Exhaust Gas Recirculation Control Circuit

What does this mean?

What are the Possible Causes of the DTC P0403 Pontiac?

Faulty Exhaust Gas Recirculation (EGR) Valve
Exhaust Gas Recirculation Valve harness is open or shorted
Exhaust Gas Recirculation Valve circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P0403 Pontiac?

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 P0403 Pontiac 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.

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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.

Frequently Asked Questions about P0403 Pontiac Code

1. What are common symptoms of OBDII code P0403 in a Pontiac?

The common symptoms of code P0403 in a Pontiac may include rough idling, engine stalling, decreased fuel efficiency, and the illumination of the check engine light.

2. What does OBDII code P0403 on a Pontiac indicate?

Code P0403 indicates a problem with the Exhaust Gas Recirculation (EGR) control circuit in the Pontiac, specifically a circuit malfunction.

3. What are some possible causes of OBDII code P0403 in a Pontiac?

Possible causes of code P0403 in a Pontiac include a faulty EGR valve, damaged wiring or connectors in the EGR circuit, a clogged EGR passage, or a malfunctioning EGR position sensor.

4. How can I diagnose OBDII code P0403 in my Pontiac?

Diagnosing code P0403 involves using a scan tool to retrieve the code, checking the EGR valve and its connections for damage, testing the EGR position sensor, and inspecting the EGR passages for blockages.

5. Can I continue driving my Pontiac with OBDII code P0403 present?

It is not recommended to drive your Pontiac with code P0403 present, as it can lead to engine performance issues and potential damage if left unresolved.

6. How can I repair OBDII code P0403 in my Pontiac?

Repairing code P0403 may involve replacing the EGR valve, repairing damaged wiring or connectors, cleaning out the EGR passages, or replacing the EGR position sensor as needed.

7. Is it possible to reset OBDII code P0403 in a Pontiac without fixing the underlying issue?

Resetting the code without fixing the underlying issue will likely result in the code reappearing once the vehicle is driven and the ECU detects the same problem.

8. Can a clogged EGR passage cause OBDII code P0403 in a Pontiac?

Yes, a clogged EGR passage can restrict the flow of exhaust gases and cause code P0403 to trigger in a Pontiac due to improper EGR operation.

9. How important is it to address OBDII code P0403 promptly in a Pontiac?

It is important to address code P0403 promptly in a Pontiac to prevent further engine damage, restore proper emissions control, and maintain optimal vehicle performance.

10. Will fixing OBDII code P0403 in my Pontiac improve fuel efficiency?

Fixing code P0403 in your Pontiac can improve fuel efficiency by ensuring proper EGR system operation, which helps optimize combustion and reduce emissions.