EGR malfunction code

hossak8 · 07-26-2003, 10:19 PM

'98 2.5RS. How does the ECU determine there is an EGR malfunction? Scanning P0400; no other codes. What sensors detect this condition? Thanks

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hossak8 · 08-14-2003, 12:07 AM

keep those replies coming.

Mulder · 08-14-2003, 12:35 AM

There is no specific sensor that monitors the EGR. The ECU will check for changes in vacuum and/or 02 readings when it operates the EGR, and if it doesn't see the change that indicates the valve is operating properly a code will set. If you have this code by itself your EGR valve may have failed or the passages may be clogged.

hossak8 · 08-14-2003, 09:30 AM

Thanks Mulder. The engine I have in my car is a 2.5 from Japan, and has no EGR port in the head. I had to use my original intake manifold, and have the port plugged. Is it possible to plug vaccum lines in order to fool the ECU? If so what lines could I eliminate without messing anything else up?

Mulder · 08-15-2003, 08:43 AM

I don't think you can fool the ECU because it is looking for changes in sensor signals when the EGR operates, and I don't know how you would fake that.
For starters you should get the engine manual for your car and find out exactly what parameters are required for that code to set.

rogue · 09-20-2005, 03:08 PM

It's the bump from Hell, cuz I searched!

I have, basically, the same problem... new heads on an EJ22 that don't have an EGR port, and I've just closed up the port on the intake manifold for now... but it means I throw a CEL after a while.

Do I have to bore into the block to fix this? Can I tap off the exhaust somewhere?

jamesfacts · 09-20-2005, 03:52 PM

Quote:

Originally Posted by rogue

It's the bump from Hell, cuz I searched!

I have, basically, the same problem... new heads on an EJ22 that don't have an EGR port, and I've just closed up the port on the intake manifold for now... but it means I throw a CEL after a while.

Do I have to bore into the block to fix this? Can I tap off the exhaust somewhere?

You can actually just tap the intake pipe that runs from the airbox to the TB - try to find an airbox from a 1.8 Impreza with the hole pre-drilled in the box for just such a hose.

rogue · 09-20-2005, 03:55 PM

Quote:

Originally Posted by americanyouth

You can actually just tap the intake pipe that runs from the airbox to the TB - try to find an airbox from a 1.8 Impreza with the hole pre-drilled in the box for just such a hose.

Tap that... to the EGR port on the intake? How will that work? It's all just intake air...

jamesfacts · 09-20-2005, 05:36 PM

Quote:

Originally Posted by rogue

Tap that... to the EGR port on the intake? How will that work? It's all just intake air...

Right, the sensor just wants to see some air under pressure.

rogue · 09-20-2005, 06:35 PM

Quote:

Originally Posted by americanyouth

Right, the sensor just wants to see some air under pressure.

You crafty little dickens

I'll try that, definitely easier than messing with the exhaust.

jamesfacts · 09-21-2005, 10:04 AM

Quote:

Originally Posted by rogue

You crafty little dickens

I'll try that, definitely easier than messing with the exhaust.

Yup, this is what we did with my buddy (drewdogg)'s swap from a newer EGR 1.8 motor to an older 2.2. Worked out just fine.

07-26-2003, 10:19 PM	#1
hossak8 Scooby Newbie Member#: 20503 Join Date: Jun 2002 Location: Northern Catskills Vehicle: '98 2.5RS '05 WRX	EGR malfunction code '98 2.5RS. How does the ECU determine there is an EGR malfunction? Scanning P0400; no other codes. What sensors detect this condition? Thanks * Registered users of the site do not see these ads.

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08-14-2003, 12:07 AM	#2
hossak8 Scooby Newbie Member#: 20503 Join Date: Jun 2002 Location: Northern Catskills Vehicle: '98 2.5RS '05 WRX	keep those replies coming.

08-14-2003, 12:35 AM	#3
Mulder Trust no one Moderator Member#: 11170 Join Date: Oct 2001 Chapter/Region: Tri-State Location: NYC Vehicle: 02 WRX 05 GTO/11 Sonata(!)	There is no specific sensor that monitors the EGR. The ECU will check for changes in vacuum and/or 02 readings when it operates the EGR, and if it doesn't see the change that indicates the valve is operating properly a code will set. If you have this code by itself your EGR valve may have failed or the passages may be clogged.

08-14-2003, 09:30 AM	#4
hossak8 Scooby Newbie Member#: 20503 Join Date: Jun 2002 Location: Northern Catskills Vehicle: '98 2.5RS '05 WRX	Thanks Mulder. The engine I have in my car is a 2.5 from Japan, and has no EGR port in the head. I had to use my original intake manifold, and have the port plugged. Is it possible to plug vaccum lines in order to fool the ECU? If so what lines could I eliminate without messing anything else up?

08-15-2003, 08:43 AM	#5
Mulder Trust no one Moderator Member#: 11170 Join Date: Oct 2001 Chapter/Region: Tri-State Location: NYC Vehicle: 02 WRX 05 GTO/11 Sonata(!)	I don't think you can fool the ECU because it is looking for changes in sensor signals when the EGR operates, and I don't know how you would fake that. For starters you should get the engine manual for your car and find out exactly what parameters are required for that code to set.

09-20-2005, 03:08 PM	#6
rogue Bonkers status: Clonked Super Moderator Member#: 7977 Join Date: Jul 2001 Chapter/Region: MAIC Location: Sterling, VA Vehicle: 100% Abuse	It's the bump from Hell, cuz I searched! I have, basically, the same problem... new heads on an EJ22 that don't have an EGR port, and I've just closed up the port on the intake manifold for now... but it means I throw a CEL after a while. Do I have to bore into the block to fix this? Can I tap off the exhaust somewhere?