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Guest Message by DevFuse

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P0400, 96 Legacy GT, 2.5 Automatic

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8 replies to this topic

#1 lmdew



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Posted 07 February 2009 - 09:21 PM

The car had this code when I got it. I cleared the code, P0400 EGR and it was gone for about 100 miles.

A shop had put a new EGR Valve on it before I got it.

I checked all the vacuum lines, and changed the following off another 2.5 manifold I had:

EGR Valve
EGR Solenoid
EGR Transducer (round part above and forward of the EGR volve.

I also blew out the lines and checked for leaks.

I drove it about 30 miles with the D-Check (green connector) hooked up and it passed the check.

Three days later (200 miles) , the code is back :>(

What to check next?

PS I sold this car, but want to fix this problem for the new owner. I thought I had it fixed.
Thanks Larry

#2 ShawnW


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Posted 07 February 2009 - 09:30 PM

Carbon buildup in the head where the EGR pipe joins to it?

#3 fleming442


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Posted 07 February 2009 - 09:45 PM

Just throwin' darts in the dark, but.....

wouldn't an over-rich condition throw an EGR malfunction? I was just thinking that a valve stuck shut would be rich and one stuck open would be lean. So, if something else caused the mixture problem, but it wasn't enough change to trigger P0420...... Just thinking out loud; don't hang me yet!

#4 OB99W


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Posted 07 February 2009 - 10:24 PM

Larry --

1) Warm the engine, then verify if you can see the EGR valve operate if you rev the engine.
2) With the engine idling, disconnect the vacuum hose at the EGR valve, and apply some vacuum to the valve (just a few inches should be enough) with either a hand pump or even sucking on a length of hose by mouth. The valve should operate, and if the exhaust passages are okay, the idle should significantly falter.

Let us know what happens in each case.

#5 lmdew



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Posted 08 February 2009 - 05:58 AM

Thanks for the info, I'm on the road for the week so it will be a bit before I can get back to the car. I'll check as advised and see what I can find out.

Thanks Again!

#6 idosubaru


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Posted 08 February 2009 - 11:52 AM

Replace the little round air filter in line with the vacuum hose on the passengers side.

Follow the vacuum hoses from the solenoid on the passengers side strut tower. one that runs to the engine area will have a small round filter (about the size of a quarter) on it.

replace that filter. $7 from Subaru.

#7 lmdew



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Posted 22 February 2009 - 07:30 AM

Replaced the small filter and checked the EGR at idle for opening and flow. It checked good and the code has not come back.

The Crank Sensor was also flagged, the PO had the car checked several times and the Mechanics had said it need a crank sensor.
When I pulled it out I found the 2 wires going to the sensor bare right at the back of the plug. I repaired the wiring and its good to go.

Thanks for the assistance!

#8 ShawnW


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Posted 23 January 2012 - 08:23 PM

I just ordered one of these for a customer. Subaru PN 22633AA010 $7.50 and available still if anybody needs one I can ship it. They are stocked at the dealer here.

#9 jarl


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Posted 23 January 2012 - 09:16 PM

Shawn: that part number gives me a "Throttle sensor ay" for $273 :confused:

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