P1403 – Exhaust Flap Control Circuit High (some manufacturers)

P1403 Diagnostic Trouble Code: EGR System Fault

The P1403 code indicates a problem with the Exhaust Gas Recirculation (EGR) system. This is a generic powertrain code that applies to many makes and models.

Urgency and Driving with P1403

If your vehicle is displaying a P1403 code, you can usually continue driving in the short term. However, it's best to diagnose and fix the issue as soon as possible to prevent potential engine damage from running rich. Schedule an appointment with your mechanic or dealer in the next few days.

Parts Involved

The main component implicated with a P1403 code is the EGR valve. The EGR system recirculates a portion of the exhaust gases back into the engine intake to lower combustion temperatures and reduce NOx emissions.

The EGR valve is an electrically controlled valve that opens and closes to regulate the flow of exhaust gases. It is typically located on the intake manifold or near the throttle body. These valves receive a pulse width modulated signal from the ECU to regulate exhaust gas flow.

Common Causes

Some of the most frequent reasons for a P1403 code include:

• Carbon buildup restricting the EGR valve and passages
• Faulty EGR valve
• Damaged or disconnected electrical connectors and wiring to the EGR valve
• Malfunctioning EGR control solenoid
• Leaking or blocked EGR vacuum lines

Diagnosis

To properly diagnose a P1403 code, follow these steps:

1. Visually inspect the EGR valve, wiring, and vacuum lines for obvious damage or carbon buildup. Clean any excess carbon.

2. Check the EGR valve and control solenoid electrical connectors are secure and wiring is intact. Repair any issues.

3. Using a scan tool, command the EGR valve to open and close while monitoring EGR position sensor voltage. The voltage should change smoothly.

4. Test the EGR valve and control solenoid operation using a vacuum pump. The valve should hold vacuum and open/close when commanded. Replace if faulty.

5. If no other issues are found, perform an exhaust back pressure test to check for restrictions in the EGR passages or manifold.

Repair and Cost

Common repairs for a P1403 code include:

• Cleaning the EGR valve and passages: $50-100
• Replacing the EGR valve: $200-500 (€180-450)
• Replacing the EGR control solenoid: $100-200 (€90-180)
• Repairing damaged wiring: $50-200 depending on extent

Parts costs will vary by vehicle make and model. Labor is typically 1-2 hours at the standard shop rate.

Prevention

To help prevent EGR system issues:

• Use high quality fuel and change engine oil on schedule
• Address any performance issues promptly to minimize carbon buildup
• Have the EGR system cleaned every 50,000 miles (80,000 km)

Related Codes

Other codes commonly seen with P1403 include:

• P0400 – EGR flow malfunction
• P0401 – EGR insufficient flow
• P0402 – EGR excessive flow
• P0404 – EGR valve circuit range/performance
• P1404 – EGR closed valve pintle error

If you have any other questions about diagnosing and repairing an EGR system fault, consult your vehicle's factory service manual or a qualified mechanic. Proper testing is important to avoid unnecessary parts replacement.

Frequently Asked Questions About P1403

What does the P1403 code mean?

P1403 is a generic powertrain code that indicates a problem with the Exhaust Gas Recirculation (EGR) system. The code definition is typically "Exhaust Gas Recirculation Flow Malfunction", but the exact wording may vary by vehicle manufacturer.

Is it safe to drive with a P1403 code?

In most cases, you can continue driving safely in the short term with a P1403 code. However, you should diagnose and repair the underlying issue as soon as possible to prevent potential engine damage from the EGR system not functioning properly.

What are the common symptoms of a P1403 code?

Vehicles with a P1403 code may experience:

• Check Engine Light illuminated
• Rough idle
• Pinging or knocking under acceleration
• Reduced fuel economy
• Failed emissions test

What are the common causes of a P1403 code?

Some of the most frequent causes of a P1403 code include:

• Clogged or faulty EGR valve
• Vacuum leaks in the EGR system
• Malfunctioning EGR control solenoid
• Faulty EGR position sensor
• Damaged or disconnected EGR electrical connectors and wiring

How do you diagnose a P1403 code?

To properly diagnose a P1403 code:

1. Visually inspect the EGR system components, wiring and vacuum lines.

2. Test the EGR valve and control solenoid operation using a scan tool and vacuum pump.

3. Check the EGR position sensor voltage with a multimeter.

4. Inspect the EGR passages for carbon buildup or blockage.

5. Verify there are no exhaust leaks before the EGR valve.

Can a P1403 code cause a vehicle to fail an emissions test?

Yes, a malfunctioning EGR system that sets a P1403 code will likely result in a failed emissions test. The vehicle will need to be repaired and the code cleared before it will pass inspection.

What repairs are commonly needed to fix a P1403 code?

Depending on the root cause, common repairs for a P1403 code include:

• Cleaning the EGR valve and passages
• Replacing the EGR valve
• Replacing the EGR control solenoid
• Repairing damaged EGR electrical wiring
• Replacing faulty EGR position sensor

How much does it typically cost to repair a P1403 code?

The cost to repair a P1403 code can range from $50-500 depending on the issue:

• Cleaning EGR system: $50-100
• Replacing EGR valve: $200-500
• Replacing control solenoid: $100-200
• Electrical repairs: $50-200+

Can I clean my EGR valve myself?

In many cases, a clogged EGR valve can be cleaned to restore proper function. This involves removing the valve and carefully scraping/cleaning away any carbon deposits. However, if the valve is physically damaged or stuck open/closed, cleaning will not repair it and replacement is necessary.

How often should the EGR system be serviced?

Most vehicle manufacturers do not specify a regular maintenance interval for the EGR system. However, having the EGR valve and passages cleaned every 50,000 miles can help prevent issues.

What happens if I unplug my EGR valve?

Unplugging the EGR valve electrical connector will cause the valve to stay closed. This will prevent exhaust gases from recirculating and likely trigger a check engine light. While this isn't immediately harmful, it can lead to increased combustion temperatures, knocking, and emissions issues over time.

Is it okay to block off or delete my EGR system?

No, the EGR system is an important emissions control device. Blocking or deleting it is illegal, will cause the check engine light to turn on, and will result in a failed emissions test. It can also lead to engine knock and potential damage under certain conditions.

Can a P1403 code be caused by an exhaust leak?

Yes, an exhaust leak before the EGR valve can allow unmetered air to enter the EGR system. This can cause incorrect EGR flow and set a P1403 trouble code.

Will disconnecting the battery clear a P1403 code?

Disconnecting the battery will clear the P1403 code and turn off the check engine light. However, if the underlying problem is not repaired, the code will return as soon as the fault is detected again, usually after a few drive cycles.

How do I test my EGR valve?

To test an EGR valve:

1. Visually inspect for damage and carbon buildup.

2. At idle, command the EGR valve open and closed using a scan tool. You should hear the valve clicking.

3. Use a vacuum pump to apply vacuum to the EGR valve. The valve should hold steady vacuum and the plunger should move.

4. With the engine running, manually open the EGR valve. The idle should become rough or the engine may stall.

If the EGR valve fails any of these tests, it needs to be cleaned or replaced.

What other codes may be present along with P1403?

Related codes that may appear along with P1403 include:

• P0400 – Exhaust Gas Recirculation Flow Malfunction
• P0401 – Exhaust Gas Recirculation Flow Insufficient
• P0402 – Exhaust Gas Recirculation Flow Excessive
• P0403 – Exhaust Gas Recirculation Circuit Malfunction
• P0404 – Exhaust Gas Recirculation Circuit Range/Performance
• P1400 – Exhaust Gas Recirculation Valve Stuck Open

Can a faulty EGR valve cause a misfire?

Yes, a stuck open EGR valve can allow exhaust gases to enter the intake manifold when not needed. This can dilute the air/fuel mixture and cause a lean misfire condition, especially at idle.

What does EGR stand for?

EGR stands for Exhaust Gas Recirculation. The EGR system routes small amounts of exhaust gas back into the intake to lower peak combustion temperatures and reduce NOx emissions.

Where is the EGR valve located?

The EGR valve is typically located on the intake manifold or near the throttle body on the upper engine. It will have coolant lines and an electrical connector running to it. On some vehicles, it may be located lower near the exhaust manifold.

Can a bad catalytic converter cause a P1403 code?

No, a faulty catalytic converter will not directly set a P1403 code, as it is after the EGR system in the exhaust stream. However, other exhaust issues like leaks before the EGR valve can cause a false P1403.

If you have any other questions about troubleshooting OBD-II code P1403, consult the factory repair information for your specific vehicle or a professional technician.