P0404 Acura Exhaust Gas Recirculation Control Circuit Range/Performance

Description

OBD-II Trouble Code Description for P0404 Acura

Exhaust Gas Recirculation Control Circuit Range/Performance

What does this mean?

OBD2 Code P0404 Acura definition:
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 Acura, 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

Possible sumptoms of OBD code P0404 Acura
There may be no symptoms of a P0404 Acura 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

Possible causes of OBD code P0404 Acura
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.

Related Codes

p-400 p0401 p0402 p0403

The OBD2 Code Information Be Applicable For Acura:

2014 Acura RLX,2014 Acura MDX,2013 Acura SUV-X Concept,2013 Acura RDX,2013 Acura NSX Concept,2013 Acura MDX Concept,2013 Acura ILX Endurance Racer,2013 Acura ILX,2012 Acura TL,2012 Acura RLX Concept,2012 Acura NSX Concept,2012 Acura ILX Street Build Concept,2012 Acura ILX Concept,2011 Acura TSX Sport Wagon,2011 Acura TSX Sedan,2010 Acura ZDX,2010 Acura TSX V6,2010 Acura RDX,2010 Acura MDX,2009 Acura ZDX Concept,2009 Acura TSX,2009 Acura TL,2009 Acura RL,2007 Acura TSX,2007 Acura TL Type-S,2007 Acura TL,2007 Acura RDX,2007 Acura MDX,2007 Acura Advanced Sports Car Concept,2006 Acura RDX Prototype,2006 Acura MD-X Concept,2006 Acura Advanced Sedan Concept,2005 Acura TSX A-Spec Concept,2005 Acura TSX,2005 Acura TL,2005 Acura RSX Type-S,2005 Acura RSX A-Spec Concept,2005 Acura RSX,2005 Acura RL with ASPEC Performance Package,2005 Acura RL ASPEC Concept,2005 Acura RL,2005 Acura RDX Concept,2005 Acura NSX,2005 Acura MDX,2004 Acura TL with ASPEC Performance Package,2004 Acura TL 25 Hours of Thunderhill,2004 Acura RL Prototype,2004 Acura 3.2 TL,2003 Acura TL ASPEC Concept,2003 Acura 3.2 CL Type-S,2002 Acura NSX sketches,2001 Acura NSX-T,2001 Acura Integra

Note:

1. The list of automotive Makes at the right edge of the screen. The currently selected ODB-ii codes is for the Acura makes.

2. Look up the other OBD II Trouble Codes, please use the search box. Enter the 5 character trouble codes in the search box and submit the search.

3. Don’t assume a particular OBD-II code means the same for other auto manufacturers as there are many makes specific codes in use.

4. If your OBD-II trouble codes are for a different car, select that vehicle series before searching for the diagnostic codes because not all OBD2 codes used by one manufacture are used by the other makes.

5. The information contained on this site is presented for informational purposes only. We are not responsible for any actions you take on your vehicle. If you have any doubt as to repairs on your vehicle, please contact your technician.