DTC P0403 On 6.0 Powerstroke: Diagnosis and Fixing Process

The 6.0L Powerstroke is notorious for its exhaust gas recirculation EGR issues. And as a result, if you own a 6.0L Powerstroke truck, the p0403 6.0 Powerstroke error code is one you are likely to encounter.

So what exactly does this Code mean, and more importantly, what causes it? These are some of the topics we will cover in this article. Along with p0403 Code how to fix.

Causes Of p0403 6.0 Powerstroke DTC Error And How Fix It?

What is P0403 – EGR circuit malfunction?

Before looking at the causes, we must first understand the problem. The EGR system helps reduce the amount of nitrogen oxide gases from the exhaust system. This allows the vehicle to minimize emissions, as nitrogen oxide is harmful to the environment.

The Powertrain Control Module will go through a P0403 error when it detects an error with the EGR system. This typically relates to the control circuit of the EGR. And you will get the Code when the control module detects a short circuit or open circuit in the EGR vacuum control solenoid.

Bad wiring of the solenoid will also cause the PCM to throw a P0403 error code.

What Causes The DTC P0403 problem

Now that we know what the problem is, it’s time to look at what causes it. Several things can be to blame for this error code.

Short or Open EGR valve control Circuits

One of the common causes of this error is a short or open circuit of the EGR valve. Typically, when closed, the valve position sensor will have a voltage of 0.8 volts. When fully opened, the valve sensor will read 3.8 valves or closer to 4.0 volts.

The sensor should not read above 5 volts or 0 volts. When this happens, the PCM will return a P0403 error code meaning there is a short or open circuit in the EGR valve control circuit.

EGR Delete Process

Deleting the EGR is something some people resort to for improved performance. However, this process can result in the P0403 error code being returned. This is because the deletion process typically involves removing the cooler and replacing or blocking the up-pipe.

In most cases, the EGR valve remains connected. The valve will be the one causing the error code to be displayed.

Damaged Solenoid

Another common cause is a defective solenoid. The EGR solenoid is responsible for recirculating exhaust gases back into the intake manifold. This results in the dilution of the oxygen entering the oxygen, as it is replaced by some of the inert gases from the exhaust.

This helps reduce nitrogen oxide levels. The PCM will throw the P0403 error code when this solenoid is damaged.

Defective EGR Valve

Problems with the EGR valve will also result in this Code being returned. A defective valve or electrode is another cause of this error code.

Issues with EGR vacuum

The vacuum control solenoid can also be open or short-circuit, causing the P0403 DTC code. The Code can also result from a line leak in the EGR vacuum.

Issues with Wiring and Connection

The EGR wiring can also be defective or not correctly done, causing this issue. Another issue can be the solenoid connection becoming loose.

Symptoms of P0403 on 6.0 Powerstroke

Certain signs indicate an issue with the EGR, which will result in the P0403 DTC code; these symptoms are;

Check Engine Light is on

the first sign of P0403 DTC code issues will be the check engine light is on. This is usually a general sign of something wrong with the engine. The cause can be electrical problems with the EGR.

Poor Acceleration and Low Fuel Economy

An issue with the EGR solenoid, one of the causes of the P0403 DTC code, will result in a poor air-to-fuel ratio, resulting in poor acceleration and fuel economy. Thus another sign of this DTC code is poor acceleration and low fuel economy.

Engine pinging and knocks

This is usually due to a failure with the EGR control solenoid. When it fails, it can disable the EGR system leading to high temperatures in the cylinder, which causes the engine to ping and knock.

Awful Excessive Odor

The excessive odor comes from the exhaust system as the EGR cannot recirculate the exhaust gases effectively.

How to Diagnose A P0403 DTC code

To diagnose a P0403 DTC code, there are several things you need to do;

  1. First, check to see if there are no other technical issues and DTC codes being returned. If there are other codes, it may be a more severe engine problem.
  2. Do a test drive with an OBD-ii scan tool connected and check the live data on the scan tool.
  3. If you get the P0403 Code, inspect the wiring and connections of the EGR control solenoid. Also, check the EGR temperature sensor.
  4. If the wiring is intact and properly aligned, inspect the valve vacuum solenoid for an open or short circuit in the solenoid.

Difference Between P0403 and P0405 DTC codes

The P0403 and P0405 DTC codes relate to the EGR and can indicate a problem with the EGR. However, they typically do not relate to the same issues. The P0403 is usually associated with issues with the control circuit, the EGR valve, and the solenoid.

An issue with these components will lead to the DTC P0403 code being returned. The P0405 DTC relates to the EGR sensor, particularly the voltage. When the PCM detects a low voltage from the sensor, it returns the P0405 DTC.

How To Fix the P0403 Code?

Fixing issues caused by the P0403 DTC will depend on what is causing the problem.

  1. Replacing the solenoid should fix the issue if the cause is a short or an open EGR vacuum solenoid.
  2. Replacing the connector to the EGR vacuum control solenoid should also fix the issue if the connector is corroded.
  3. If it’s an issue with the EGR vacuum control solenoid wiring, you can get it fixed or replaced. Or replace a leaking vacuum line.

Is the P0403 Code dangerous

As mentioned, this Code is usually related to a malfunction in the EGR system. This will most likely result in dangerous fumes coming from your vehicle. This issue can also lead to more damage to the engine due to increased temperatures in the cylinder.

FAQ

Can I Drive with a P0403 code active?

While you can drive with the P0403 Code active, it is not advisable. Firstly, you will fail any emissions test if you need one. Also, leaving the issue unresolved can lead to a more severe problem, and you will spend more at the gas station.

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