Question about 2003 Chevrolet Impala

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Had EGR valve replaced 3 mos ago. Now I'm getting P0300 & P0404

Codes. Car is now very sluggish & doesn't go uphill without a flashing engine light. Took the car back to the dealer & had them reset EGR since that is what the P0404 code is supposed to be. What else can I do??

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  • imindira Jun 04, 2009

    2003 impala-last 4 of vin are 2070

  • imindira Jun 04, 2009

    Sorry, last 8 are 39242070

  • Dr Honeydew May 11, 2010

    may i have you vin #?



    if memory serves me right (and it probably isnt) there was a new computer calibration available for a "false" p0404 on the impala's...i can check this for you with your vin #...the last eight digits of it will do...but the p0404 really does not explain the flashing cel...a flashing cel indicates there is a catalyst damaging event occuring, this is typicaly due to a misfiring tyoe scenario...there must be other codes stored

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Turns out they should have put in a new fuel pump rather than the EGR valve. Hopefully this will solve the problem.

Posted on Jun 10, 2009

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I know that your code says egr but it sounds more like your oxygen sensor is done .

Posted on Jun 04, 2009

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1 Answer

08' town and country shows codes p0406, p0404, p0301, p0300


egr valve is stuck open at idel exhaust gas is entering engin causing lean condition and missfire your po300 301 codes replace egr and clear codes

Feb 09, 2014 | 2005 Chrysler Town & Country

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My 02 grand am gt is acting up engine light is on went to autoparts store to get it checked out it threw codes p1404, p0404 and p0300 i already changed the egr valve twice and it wont help can someone plz...


code p0404 refers to Exhaust gas recirculation system (EGR)--range performance problem--- causes---hose leakage--wiring---EGR valve/solenoid
code p0300 refers to random/multiple cylinder/s ---misfire detected.---causes---spark plugs---ht leads---injectors--ignition coils---low compression ---wiring. Remember it is best to use genuine sensors/solenoids as the cpu is set to them. Try changing the egr solenoid

PLEASE RATE THIS REPLY FOR ACCURACY

Mar 24, 2013 | 2000 Pontiac Grand Am GT

1 Answer

2006 Pontiac G6 shifting hard, engine very sluggish and mpg under 15.


You have a random engine misfire. P0300. That is the root cause. Basically this P0300 code means that the car's computer has detected that not all of the engine's cylinders are firing properly. This would also cause hard shifts due to low engine power.
Read on please.




A P0300 diagnostic code indicates a random or multiple misfire. If the last digit is a number other than zero, it corresponds to the cylinder number that is misfiring. A P0302 code, for example, would tell you cylinder number two is misfiring. Unfortunately, a P0300 doesn't tell you specifically which cylinder(s) is/are mis-firing, nor why.
Symptoms:
•the engine may be harder to start
•the engine may stumble / stumble, and/or hesitate
•other symptoms may also be present
Causes:
•Faulty spark plugs or wires
•Faulty coil (pack)
•Faulty oxygen sensor(s)
•Faulty fuel injector(s)
•Burned exhaust valve
•Faulty catalytic converter(s)
•Stuck/blocked/leaking EGR valve / passages
•Faulty camshaft position sensor
•Defective computer

Apr 24, 2017 | Cars & Trucks

2 Answers

01 montero sport 4x4 p0300 code random misfire very sluggish and idle is lower than normal. will come and go but is getting worse


DTC P0300 - Random/Multiple Cylinder Misfire Detected
Basically this means that the the car's computer has detected that not all of the engine's cylinders are firing properly.

A P0300 diagnostic code indicates a random or multiple misfire. If the last digit is a number other than zero, it corresponds to the cylinder number that is misfiring. A P0302 code, for example, would tell you cylinder number two is misfiring. Unfortunately, a P0300 doesn't tell you specifically which cylinder(s) is/are mis-firing, nor why.

Symptoms may include:
the engine may be harder to start
the engine may stumble / stumble, and/or hesitate
other symptoms may also be present

A code P0300 may mean that one or more of the following has happened:
Faulty spark plugs or wires
Faulty coil (pack)
Faulty oxygen sensor(s)
Faulty fuel injector(s)
Burned exhaust valve
Faulty catalytic converter(s)
Stuck/blocked EGR valve / passages
Faulty camshaft position sensor
Defective computer

Possible Solutions
If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.

If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

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Feb 09, 2012 | 2001 Mitsubishi Montero Sport 4WD

1 Answer

I am getting OBD-II trouble code P0404 on my 2001 Chevy Malibu, and want to know, what I can do to correct that?


Here is the website I use for OBDII codes:
http://www.obd-codes.com/trouble_codes/

And it says:
P0404 - Exhaust Gas Recirculation Circuit Range/Performance OBD-II Trouble Code Technical Description

Exhaust Gas Recirculation Circuit Range/Performance
What does that mean?

The EGR (Exhaust Gas Recirculation) system's purpose is to redirect exhaust gas back into the cylinders. Since exhaust gas is inert, it displaces oxygen and fuel, thereby lowering cylinder temps, which, in turn, lowers oxides of nitrogen emissions. For that reason it needs to be carefully metered into the cylinders (via the EGR valve) so as not to adversely affect the engine's performance. (Too much EGR and the engine won't idle).
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If you have a P0404, then the EGR valve is likely an electrically controlled EGR valve instead of a vacuum controlled EGR valve. Also, the valve will usually have a feedback system built into it that informs the PCM (Powertrain Control Module) what position the valve is in; open, closed, or somewhere in between. The PCM needs to know this to determine whether or not the valve is operating as needed. If the PCM determines that the valve should be operating, but the feedback circuit shows that the valve is not open, this code will set. Or if the PCM determines the valve should be closed but the feedback signal indicates that the valve is open, this code will set.
Symptoms

There may be no symptoms of a P0404 DTC other than the MIL (malfunction indicator lamp) or check engine light. However, Exhaust Gas Recirculation systems are inherently problematic due to carbon buildup in the intake manifold, etc. This normal buildup can lodge in an EGR valve, holding it open when it should be closed. If this is the case, the engine may idle rough, or not at all. If the valve has failed and is NOT opening, then symptoms would be higher combustion temps and as a result, higher Nox emissions. But the latter symptoms aren't going to be noticeable to a driver.
Causes

Usually this code points to either carbon buildup or a bad EGR valve. However that doesn't rule out the following:

  • Open or short in the 5 Volt reference circuit
  • Open or short in the ground circuit
  • Open or short in the PCM controlled voltage circuit
  • Bad PCM (less likely)
Possible Solutions
  1. Using a scan tool command the EGR valve to open while watching the actual EGR position (it will probably be labeled "desired EGR" or something similar). The actual EGR position should be very close to the "desired" EGR position. If it is, then the problem is likely intermittent. It may have been a lodged piece of carbon that has since dislodged, or it could be a bad EGR valve winding that intermittently opens or shorts as the valve temperature changes.
  2. If the EGR "desired" position is not close to the "actual" position, then unplug the EGR sensor. Check for a good 5 Volt reference voltage to the connector. If it doesn't show a reference voltage, repair an open or short in the 5 Volt reference circuit.
  3. If there is a 5 volt reference voltage, activate the EGR with the scanner, monitor the EGR ground circuit with a DVOM (Digital Volt/Ohm meter). It should indicate a good ground. If it doesn't then repair the ground circuit.
  4. If there is a good ground, then check the control circuit. It should indicate voltage that varies according to the percentage that the EGR is open. As it's open more, the voltage should increase accordingly. If it does, then replace the EGR valve.
  5. If the voltage doesn't increase incrementally, then repair open or short in EGR control circuit.

Aug 07, 2011 | 2001 Chevrolet Malibu

1 Answer

What is a p0404 code


P0404 - Exhaust Gas Recirculation Circuit Range/Performance
The EGR (Exhaust Gas Recirculation) system's purpose is to redirect exhaust gas back into the cylinders. Since exhaust gas is inert, it displaces oxygen and fuel, thereby lowering cylinder temps, which, in turn, lowers oxides of nitrogen emissions. For that reason it needs to be carefully metered into the cylinders (via the EGR valve) so as not to adversely affect the engine's performance. (Too much EGR and the engine won't idle).

If you have a P0404, then the EGR valve is likely an electrically controlled EGR valve instead of a vacuum controlled EGR valve. Also, the valve will usually have a feedback system built into it that informs the PCM (Powertrain Control Module) what position the valve is in; open, closed, or somewhere in between. The PCM needs to know this to determine whether or not the valve is operating as needed. If the PCM determines that the valve should be operating, but the feedback circuit shows that the valve is not open, this code will set. Or if the PCM determines the valve should be closed but the feedback signal indicates that the valve is open, this code will set.

Symptoms: There may be no symptoms of a P0404 DTC other than the MIL (malfunction indicator lamp) or check engine light. However, Exhaust Gas Recirculation systems are inherently problematic due to carbon buildup in the intake manifold, etc. This normal buildup can lodge in an EGR valve, holding it open when it should be closed. If this is the case, the engine may idle rough, or not at all. If the valve has failed and is NOT opening, then symptoms would be higher combustion temps and as a result, higher Nox emissions. But the latter symptoms aren't going to be noticeable to a driver.

Causes: Usually this code points to either carbon buildup or a bad EGR valve. However that doesn't rule out the following:
Open or short in the 5 Volt reference circuit
Open or short in the ground circuit
Open or short in the PCM controlled voltage circuit
Bad PCM (less likely)

Possible Solutions: Using a scan tool command the EGR valve to open while watching the actual EGR position (it will probably be labeled "desired EGR" or something similar). The actual EGR position should be very close to the "desired" EGR position. If it is, then the problem is likely intermittent. It may have been a lodged piece of carbon that has since dislodged, or it could be a bad EGR valve winding that intermittently opens or shorts as the valve temperature changes.
If the EGR "desired" position is not close to the "actual" position, then unplug the EGR sensor. Check for a good 5 Volt reference voltage to the connector. If it doesn't show a reference voltage, repair an open or short in the 5 Volt reference circuit.
If there is a 5 volt reference voltage, activate the EGR with the scanner, monitor the EGR ground circuit with a DVOM (Digital Volt/Ohm meter). It should indicate a good ground. If it doesn't then repair the ground circuit.
If there is a good ground, then check the control circuit. It should indicate voltage that varies according to the percentage that the EGR is open. As it's open more, the voltage should increase accordingly. If it does, then replace the EGR valve.
If the voltage doesn't increase incrementally, then repair open or short in EGR control circuit.


Hope this helps (remember to rate and comment this answer).

Jul 11, 2011 | 2003 Chevrolet Impala

1 Answer

I have a 2005 chevy impala 3.4l v6. I am getting the code P0300 (multiple misfire).i recently changed the spark plugs/wires/coils and have checked all vacuum lines, but my car is still idling...


Basically this means that the the car's computer has detected that not all of the engine's cylinders are firing properly.
A P0300 diagnostic code indicates a random or multiple misfire. If the last digit is a number other than zero, it corresponds to the cylinder number that is misfiring. A P0302 code, for example, would tell you cylinder number two is misfiring. Unfortunately, a P0300 doesn't tell you specifically which cylinder(s) is/are mis-firing, nor why.
Symptoms Symptoms may include:
  • the engine may be harder to start
  • the engine may stumble / stumble, and/or hesitate
  • other symptoms may also be present
Causes A code P0300 may mean that one or more of the following has happened:
  • Faulty spark plugs or wires
  • Faulty coil (pack)
  • Faulty oxygen sensor(s)
  • Faulty fuel injector(s)
  • Burned exhaust valve
  • Faulty catalytic converter(s)
  • Stuck/blocked EGR valve / passages
  • Faulty camshaft position sensor (more than likely your culprit)
  • Defective computer
Possible Solutions If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.
Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.

May 26, 2011 | 2005 Chevrolet Impala

1 Answer

Describe your 2006 Chrysler Town & Country Problem p0404 engine code


P0404 IS EGR POSITION SENSOR PERFORMANCE..YOU NEED A NEW EGR VALVE..RECOMMEND DISCONNECTING BATTERY WHILE REPLACING EGR VALVE..SOMETIMES CODE WILL NOT GO AWAY EVEN AFTER REPLACING VALVE AND CLEARING CODE WITH SCANNER..VALVE IS LOCATED ABOVE ALTERNATOR ON END OF CYLINDER HEAD..THE BOTTOM BOLT CAN BE TRICKY TO REMOVE AND HAVE HAD TO REMOVE ALTERNATOR TO GET BOLT OUT..YOU WILL NEED A NEW GASKET FOR TUBE AS WELL..ABOUT 120 BUCKS FROM DEALER(CAN)

Jul 25, 2009 | 2006 Chrysler Town & Country

1 Answer

Getting DTC code P0404 and P0420. What should I do?


The 420 will not go away with egr replacement. it means the computer has detected a problem with the catalytic converter. eGR valve is at the rear of the engine. Not easy to get to on vans.

May 05, 2009 | Oldsmobile Silhouette Cars & Trucks

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