OBD Code 404 EGR Peformance

[SloandOld]

Just joined. Have a '99 Camaro 3.8 and have the 404 EGR code coming up. Car acts up after driving it for a while and up to temp but is fine when cold. When cruising highway, go to accelerate and acts funny like it's stumbling or trying to decide if it wants to downshift. at lower speeds and go to accelerate, it's stumbling and sometimes getting like a backfire or popping sound from the throttle body. Is this being caused by the EGR being clogged up? Also, after driving then going to start the car again, it will crank longer than usual, start, then die. Then starts back up again no problem. Would like to solve this.

[LETZRIDE]

A stuck open EGR valve will cause a bad idle/misfire.

At idle the egr would normally be closed, but at cruising it should be open therefore it shouldn't misfire then.

It also should be closed at WOT, so you could notice a difference there also.

What was the exact code that you were getting 404 is not a code - my assumption is P1404? Are there any other codes that also came up?


If it is P1404 it means:

OBD II fault code P1404 is a manufacturer specific code that is defined by General Motors (Chevrolet in particular) as “Exhaust Gas Recirculation (EGR) Closed Position Performance”, and is set when the actual position of the EGR valve pintle does no coincide with the position of the EGR valve pintle the PCM (Powertrain Control Module) is expecting to see when the EGR valve is closed. Note that this code is primarily concerned with the position of the EGR valve pintle at start-up, as opposed to general issues with the amount of recirculated exhaust gas in the system at any given time


Common Causes of P1404

• Damaged, burnt, shorted, disconnected, or corroded wiring and/or connectors.
• Open circuits.
• Defective EGR valve.
• Excessive wear of moving parts of the EGR valve.
• Failed, or failing PCM. Note that this is a rare event, and the fault must be sought elsewhere before any controller is replaced.

Common Symptoms of P1404

• Loss of power that can vary from slight and barely detectable, to severe enough to immobilize a vehicle.
• Rough or erratic idling that can vary from slight to severe.
• Frequent or unpredictable stalling.
• Hard starting.
• Detonation (pinging or knocking) upon acceleration, or when the engine load increases.
• Increased fuel consumption.
• Increased levels of nitrous oxides and other harmful emissions in the exhaust stream.
• In some cases, black smoke may be visible from the tail pipe, particularly on diesel applications.

NOTE: This list of possible symptoms is not exhaustive or complete. In addition, not all, or even most of the possible symptoms listed here will always be present on all applications. Hence, the absence of one or more symptoms listed here has no diagnostic value in itself.



This link has the above information as well as a full step by step on how to diagnose and test your EGR at the bottom of their page.

[SloandOld]

A stuck open EGR valve will cause a bad idle/misfire.

At idle the egr would normally be closed, but at cruising it should be open therefore it shouldn't misfire then.

It also should be closed at WOT, so you could notice a difference there also.

What was the exact code that you were getting 404 is not a code - my assumption is P1404? Are there any other codes that also came up?


If it is P1404 it means:

OBD II fault code P1404 is a manufacturer specific code that is defined by General Motors (Chevrolet in particular) as “Exhaust Gas Recirculation (EGR) Closed Position Performance”, and is set when the actual position of the EGR valve pintle does no coincide with the position of the EGR valve pintle the PCM (Powertrain Control Module) is expecting to see when the EGR valve is closed. Note that this code is primarily concerned with the position of the EGR valve pintle at start-up, as opposed to general issues with the amount of recirculated exhaust gas in the system at any given time


Common Causes of P1404

• Damaged, burnt, shorted, disconnected, or corroded wiring and/or connectors.
• Open circuits.
• Defective EGR valve.
• Excessive wear of moving parts of the EGR valve.
• Failed, or failing PCM. Note that this is a rare event, and the fault must be sought elsewhere before any controller is replaced.

Common Symptoms of P1404

• Loss of power that can vary from slight and barely detectable, to severe enough to immobilize a vehicle.
• Rough or erratic idling that can vary from slight to severe.
• Frequent or unpredictable stalling.
• Hard starting.
• Detonation (pinging or knocking) upon acceleration, or when the engine load increases.
• Increased fuel consumption.
• Increased levels of nitrous oxides and other harmful emissions in the exhaust stream.
• In some cases, black smoke may be visible from the tail pipe, particularly on diesel applications.

NOTE: This list of possible symptoms is not exhaustive or complete. In addition, not all, or even most of the possible symptoms listed here will always be present on all applications. Hence, the absence of one or more symptoms listed here has no diagnostic value in itself.



This link has the above information as well as a full step by step on how to diagnose and test your EGR at the bottom of their page.

Thanks for the response. Will have to dig deeper. I did remove the EGR valve to check it out and it is clean and the pintle moves freely.

[LETZRIDE]

Have you verified the wiring to ensure the PCM is able to communicate with the EGR?