Skip the auto shop - Our mechanics make house calls
  1. Home
  2. Articles
  3. P0403 OBD-II Trouble Code: Exhaust Gas Recirculation Circuit Malfunction

P0403 OBD-II Trouble Code: Exhaust Gas Recirculation Circuit Malfunction

Check Engine Light

P0403 code definition

Exhaust Gas Recirculation Circuit Malfunction

What the P0403 code means

P0403 is an OBD-II generic code that indicates that the engine control module (ECM) has detected the engine exhaust gas recirculation (EGR) circuit has malfunctioned. The ECM detected a short or open circuit in the EGR vacuum control solenoid or wiring to the solenoid.

What causes the P0403 code?

  • The ECM monitors the EGR vacuum control solenoid voltage and will detect a short or open circuit to the solenoid.

  • The EGR vacuum control solenoid is shorted or open internally.

  • The solenoid connection is corroded and losing connections.

What are the symptoms of the P0403 code?

  • The Check Engine Light will be illuminated and the code is set in ECM memory.
  • The engine may have pre-ignition on acceleration.
  • The engine EGR system will be disabled by the ECM.

How does a mechanic diagnose the P0403 code?

  • Scans codes and documents the freeze frame data in order to verify the problem.

  • Clears the engine codes and road tests the vehicle to verify whether the code comes back.

  • Visually checks the wiring and connections to the EGR control solenoid along with the EGR temperature sensor.

  • Disconnects and checks the EGR valve vacuum control solenoid for a short or open circuit in the solenoid.

  • Checks solenoid connection for corrosion in connection.

Common mistakes when diagnosing the P0403 code

  • Failing to disconnect the connection to the EGR control solenoid to check the connection for a corrosion buildup that could cause an open circuit to the ECM that could set this code.

  • Failing to check the wiring harness for cut wires causing an open circuit before replacing a good solenoid.

How serious is the P0403 code?

  • An EGR system that triggers this code IN the ECM will disable the EGR system and render it inoperative.

  • The Check Engine Light being on will cause the vehicle to fail emission testing and may cause the engine to ping on acceleration.

What repairs can fix the P0403 code?

  • Replacing the shorted or open EGR vacuum solenoid
  • Replacing a corroded connector to the EGR vacuum control solenoid
  • Repairing the wiring shorted to the EGR vacuum control solenoid

Additional comments for consideration regarding the P0403 code

Code P0403 is triggered when the EGR vacuum control solenoid is not making a complete and correct circuit to the ECM. When this happens, the ECM will turn off its control of the solenoid.

Need help with a P0403 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

How to Get a Louisiana Driver's Permit
s licensing program. The first step in this program is to obtain...
Auto Safety Tips
Driving is more than a way to get from point A to point B. Owning and driving a car can also be a highly enjoyable experience. Whether a person is driving...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.


Related questions

Q: Getting a P0430 code on my Buick Century 3100.

Hi there. The code p0403 is for the EGR circuit that shows it has malfunctioned. The code p0430 is for the catalytic converter showing that its below threshold. Check the harness to the EGR and make sure that all of...

Q: P0139 HO2S-12 (Bank 1 Sensor 2) Circuit Slow Response - 2005 Honda Accord

This code indicates that the rear oxygen sensor is not properly reading the oxygen content and adjusting the air/fuel ratio as it is supposed to. This can be caused the by the sensor not working properly, the wiring to the...

Q: The truck cut out suddenly

Code P0722 is an output shaft sensor code for the transmission. While that may be an indication of an issue, it would not cause the truck to just quit. A catastrophic failure of the fuel pump, ignition system, or engine...