P0403
Fix within 1-2 weeksThe engine computer detected an electrical problem in the Exhaust Gas Recirculation (EGR) valve circuit.
Code P0403 means the engine computer detected an electrical problem in the Exhaust Gas Recirculation (EGR) valve circuit. Common causes: Faulty EGR valve (70%), wiring issues (20%). Drivability: Yes, safe to drive, but fix within 1-2 weeks. Repair cost: $50-$250 DIY, $150-$600 professional.
Can I Drive With P0403?
Yes, safe to drive
No restrictions, but address the issue promptly.
Stop driving immediately if: Flashing Check Engine Light, severe engine hesitation, stalling, or loud engine knocking.
Symptoms of P0403
- 1Check Engine Light is on
- 2Rough idle
- 3Engine hesitation or stumbling during acceleration
- 4Reduced fuel economy
- 5Engine pinging or knocking (less common with circuit fault)
Common Causes of P0403
Parts most likely causing this code, ranked by probability
The internal electrical solenoid within the EGR valve has failed, causing an open or short circuit.
70% of P0403 cases are fixed by replacing the EGR valve
Damaged, corroded, or loose wiring or a faulty connector to the EGR valve can interrupt the electrical circuit.
20% of P0403 cases are fixed by repairing wiring or connectors
A fuse protecting the EGR valve circuit or a shared emissions circuit has blown, cutting off power to the valve.
5% of P0403 cases are fixed by replacing a blown fuse
A rare internal fault within the engine computer can cause it to incorrectly report an EGR circuit malfunction.
5% of P0403 cases are fixed by addressing a PCM issue
Check These First (Before Buying Parts)
- Visually inspect the EGR valve's electrical connector and wiring for any signs of damage, fraying, or corrosion.
- Check the fuse box for any blown fuses that supply power to the engine control or emissions systems.
How to Diagnose P0403
- 1Visually inspect the EGR valve and its electrical connector for any obvious damage, corrosion, or loose connections.
- 2Check for any blown fuses in the engine bay or under the dash that are related to the engine or emissions system.
- 3Using a multimeter, test the resistance of the EGR valve solenoid across its terminals (refer to service manual for specifications).
- 4With the key on, engine off, use a multimeter to check for proper voltage and ground at the EGR valve electrical connector.
- 5If the valve tests good and power/ground are present, further diagnosis with a professional scan tool may be needed to check PCM output.
P0403 on Popular Vehicles
Honda Accord
2003-2017EGR valve solenoid failures are common on these models, leading to P0403. The valve is typically located on the intake manifold and is relatively accessible.
75% fixed by replacing the EGR valve
Ford F-150
2004-2024Ford trucks, particularly those with V8 engines, frequently experience EGR valve electrical failures. The valve can be prone to carbon buildup, which can also stress the solenoid.
70% fixed by replacing the EGR valve
Chevrolet Silverado
2007-2024EGR valve circuit issues are a known concern on Silverado models. It's important to check the wiring harness for chafing or corrosion, especially near the valve, before replacing the valve itself.
65% fixed by replacing the EGR valve
Frequently Asked Questions
What does P0403 mean?
P0403 indicates that your vehicle's engine computer has detected an electrical malfunction within the Exhaust Gas Recirculation (EGR) valve circuit. This means there's an issue with the wiring or the electrical component of the EGR valve itself, not necessarily a blockage.
Can I drive with P0403?
Yes, you can drive safely with a P0403 code. The code points to an electrical circuit issue, which typically does not cause immediate engine damage. However, you should fix it within 1-2 weeks to prevent reduced fuel economy and increased emissions.
Will P0403 clear itself?
No, P0403 will not clear itself. An electrical circuit malfunction requires a repair to resolve the underlying issue. The Check Engine Light will remain on until the fault is fixed and the code is cleared, either by the vehicle's computer after several drive cycles or with an OBD-II scan tool.
How do I fix P0403 myself?
To fix P0403 yourself, start by inspecting the EGR valve's electrical connector and wiring for damage or corrosion. Check relevant fuses. If those are good, use a multimeter to test the resistance of the EGR valve's solenoid. If the resistance is out of specification, replacing the EGR valve is the most common fix.
How much does it cost to fix P0403?
The cost to fix P0403 ranges from $50-$250 for DIY, primarily for a new EGR valve. Professionally, you can expect to pay $150-$600, which includes the part and 1-2 hours of labor.
P0403 keeps coming back - why?
If P0403 keeps coming back, it indicates the initial repair did not address the root cause. Common reasons include a faulty replacement EGR valve, overlooked wiring damage further up the harness, a persistent issue with the electrical connector, or, in rare cases, a problem with the Powertrain Control Module (PCM).
Will P0403 fail emissions/smog test?
Yes, P0403 will cause your vehicle to fail an emissions or smog test. The Check Engine Light being on, regardless of the code, is an automatic failure in most states. Additionally, a malfunctioning EGR system directly impacts exhaust gas composition.
What's the difference between P0403 and P0401?
P0403 indicates an electrical circuit malfunction within the EGR system, meaning the computer detects an issue with the wiring or the valve's solenoid. P0401, on the other hand, means 'EGR Flow Insufficient,' indicating that the EGR valve is not opening enough or is blocked, preventing proper exhaust gas flow.
P0403 on Honda Accord?
P0403 on a Honda Accord, especially models from the early 2000s to mid-2010s, is often caused by a failing EGR valve solenoid. While the valve itself might not be physically stuck, its internal electrical component fails, triggering the circuit malfunction code. Inspecting the connector and testing the valve's resistance are key diagnostic steps.
Questions to Ask Your Mechanic
Did you test the resistance of the EGR valve solenoid and compare it to factory specifications?
Good answer: Yes, I measured the resistance across the EGR valve terminals, and it was X ohms, which is outside the specified range of Y-Z ohms. This confirms an internal electrical fault in the valve.
Did you check for proper voltage and ground at the EGR valve connector with the key on?
Good answer: Yes, I confirmed there is 12 volts present at the power wire and a good ground signal at the connector, indicating the wiring from the PCM is intact.
Repair Cost Estimate
DIY Repair
Parts only
$50-$250
Shop Repair
Parts + labor
$150-$600
Save $100-$350 by doing it yourself
Difficulty
intermediate
Time
1-2 hours
Intermediate - requires basic electrical testing knowledge and tools like a multimeter, but the physical replacement of the EGR valve is often simple.
Cost of Waiting
Ignoring P0403 will lead to reduced fuel economy, increased harmful emissions, and potential engine pinging or knocking. While not immediately catastrophic, prolonged operation with a faulty EGR system can contribute to carbon buildup in the intake, which can lead to more complex and expensive repairs down the line.
While You're In There...
A new gasket is essential for a proper seal and typically comes with a new EGR valve, but confirm it's included or purchase separately to prevent exhaust leaks.
If the EGR valve is easily accessible near the throttle body, cleaning the throttle body can help remove carbon buildup and improve overall engine idle and response.
Tools You'll Need
- OBD-II scan tool
- Multimeter
- Socket/ratchet set
- Screwdrivers
- Wire brush (for cleaning connections)
P0403 is a common electrical fault in the EGR system. It's usually a straightforward repair involving replacing the EGR valve, and your vehicle's emissions and performance will improve afterward.
- Family-owned since 1957
- 990,000+ happy customers
- Fast nationwide shipping
- Easy returns
Your Next Steps
Step 1: Visually inspect the EGR valve's electrical connector and the wiring harness leading to it for any signs of damage, corrosion, or loose connections. Ensure any related fuses are intact.
Step 2: If the visual inspection doesn't reveal the problem, use a multimeter to test the resistance of the EGR valve's solenoid. Compare your reading to the specifications in your vehicle's service manual. If it's out of spec, replace the EGR valve.
Step 3: If the EGR valve tests good, use the multimeter to check for proper voltage and ground at the EGR valve connector with the key on. If power or ground is missing, trace the wiring back to the PCM or fuse box to find the break. Parts you'll likely need: new EGR valve and gasket.