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Old 08-22-2010, 04:27 PM   #1
BonesXMahones
Scooby Newbie
 
Member#: 56425
Join Date: Mar 2004
Chapter/Region: NESIC
Location: Pittsboro, NC
Vehicle:
2002 WRX
Aspen White

Default Idling/No start Issue. ECM Bad?

For the past year my WRX has sat in storage. Upon taking it out it had an idling issue. It read P0508 (Idle Control System Circuit Low Input) and P1507 (Idle Control System Malfunction (Fail-Safe)). The latter asks you to disregard that code if the P0508 is present. Running through the P0508 diagnostics as per the WRX Service Manual:

1)CHECK OUTPUT SIGNAL FROM ECM.
1)Turn the ignition switch to ON.
2)Measure the voltage between ECM and
chassis ground.
Connector & terminal
(8136) No. 10 (+) - Chassis ground (-):

The voltage measured was less than 3 volts so I progressed to step 2

2)CHECK POWER SUPPLY TO IDLE AIR CONTROL
SOLENOID VALVE.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from idle air control
solenoid valve.
3)Turn the ignition switch to ON.
4)Measure the voltage between idle air control
solenoid valve and engine ground.
Connector & terminal
(E7) No. 2 (+) - Engine ground (-)

I found that the connection between the second pin of the IACV and chassis ground was open. The flow chart says that the problem then exists between the Main Relay and the IACV.

I found all the wiring diagrams needed and progressed to disconnecting each successive connector to isolate the individual parts of the system where the open could be. Everything check out ok and when I plug them all back in and checked the connection from the main relay to IACV I got a resistance value of 0.002 ohmsÖ.perfect. I plug the main relay back in and the IACV connector, but now the car wonít start. Naturally I went back, check to make sure I plugged everything in correctly, all the pins were straight, etc to no avail.

When I turn the key to the on position the MIL will not illuminate and all the other lights (empty fuel light, etc) that are not normally on are on. When I switch the key to the off position the oil light stays barely illuminated and the coolant temperature gauge goes off the scale in the hot direction. If I unplug the relay or, obviously, the battery everything settles down. If I simply unplug the main relay and then plug it back in, it seems to act like it normally would with the key in the off position. This problem also affects Data Link Connector as my hand held code reader will no longer boot up.

The only strange thing I noticed when performing my test was that when I disconnected connector F44, which is behind the steering wheel, I mistakenly measured the harness going back to the engine compartment and the main relay. I got a reading of 21.35 KOhms. The problem is I should have gotten no reading if I read my charts correct as the system was now disconnected and there is no wiring that connects the pins I was checking.

I am totally boggled as to how my symptoms have now changed and I have progressed from a poorly running car to a car that will now not start. Iím not sure how to post pictures of the diagnostics I went through, but if anyone needs a screen print of them to better assist me, let me know.

Right now it would seem that either the relay is bad, or what I fear more, the ECM is bad. But after sitting a while I suppose anything could happen?
Any help would be much appreciated!
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Old 08-22-2010, 06:56 PM   #2
Mulder
Trust no one
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Member#: 11170
Join Date: Oct 2001
Chapter/Region: Tri-State
Location: NYC
Vehicle:
02 WRX
15 WRX/05 GTO

Default

Where was the car stored? Is it possible that mice or similar small critters got into the engine bay and/or interior and nibbled the wires? This is something that often happens to cars that sit, mice will find their way inside and eat the wires while making nests. The result is all kinds of otherwise unexplainable electrical symptoms.
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Old 08-22-2010, 09:20 PM   #3
BonesXMahones
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Member#: 56425
Join Date: Mar 2004
Chapter/Region: NESIC
Location: Pittsboro, NC
Vehicle:
2002 WRX
Aspen White

Default

Unfortunately you might be right. When I pulled the carpet back today after writing the message I found what looks like urine. I also removed my battery to look at the Relay panel wires and then found droppings. I hope I am not out of luck on this. I have found no nibbled wires anywhere. The last time I saw mice make a nest they tear everything up and make a mess. Hopefully I can find signs of wire damage somewhere so I can repair the issue.

Looks like I might just have to tear the interior apart huh?
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Old 08-23-2010, 03:10 AM   #4
Cougar4
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Member#: 53443
Join Date: Jan 2004
Location: Anchorage, AK
Vehicle:
2001 LL Bean Outback
Winestone

Default

From your statement about the coolant sensor gauge going to full scale it sounds to me that a connector didn't get connected back to the correct spot. Try disconnecting the connectors you worked with one at a time and see which one effects the coolant gauge. You should also check the fuses under the hood for a blown fuse. I think SBF-5 supplies power to the Main relay if I remember correctly. It also ties power to the OBD-2 connector for the reader and is why it didn't work.
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Old 03-12-2012, 09:30 PM   #5
surfer30
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Member#: 296898
Join Date: Oct 2011
Default

Did you ever find out root cause of the issue you were having with the not starting and the gauge oddities? I am having the same issues with my 05 WRX and I am totally boggled. Any results to correct the issues would be greatly appreciated.
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Old 03-12-2012, 10:39 PM   #6
Mulder
Trust no one
Moderator
 
Member#: 11170
Join Date: Oct 2001
Chapter/Region: Tri-State
Location: NYC
Vehicle:
02 WRX
15 WRX/05 GTO

Default

Don't expect an answer, the OP hasn't logged into the site in over a year and hasn't posted since this thread.
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Old 03-13-2012, 08:21 AM   #7
surfer30
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Member#: 296898
Join Date: Oct 2011
Default

Have you heard of anyone having the same problems as this guy was having? I have the same symptoms and I am currently leaning toward the main relay. Going to check it tonight for resistance and them go over to the ECU and check it's grounds and voltage.
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Old 03-13-2012, 01:19 PM   #8
Cougar4
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Member#: 53443
Join Date: Jan 2004
Location: Anchorage, AK
Vehicle:
2001 LL Bean Outback
Winestone

Default

First make sure that all the fuses are good and power is getting to them.
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