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Guest Message by DevFuse

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lost ground, faulty computer or bad Tps? 02 outback

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5 replies to this topic

#1 vatwell



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Posted 14 March 2013 - 03:00 PM

New to this but hoping to find some help...I have a 02 outback with the 2.5 engine, manual transmission. A few weeks ago started running very rough, felt like it was cutting out or misfiring. Have put in new plugs, fuel filter, crank position sensor and now a TPS. No change. Code was showing misfire on cylinders 1-4. Hooked up the scanner during drive and it showed the TPS cutting out. Thats when we placed it.  Odd note tho is that we ran a set of jump cables to ground the engine and it ran fine. 


Any ideas? Thanks!



#2 CNY_Dave


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Posted 14 March 2013 - 03:49 PM

Chase all the grounds first, if they aren't right then nothing else will be right.

#3 Fairtax4me



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Posted 15 March 2013 - 12:45 AM

The ECU grounds to the intake manifold somewhere near the ignition coil. Should be at least 4 ground wires coming together at that point, make sure the bolt is tight and the eyelet connectors are free of corrosion.
Also check the main engine ground near the starter.
You should also check the battery negative terminal for corrosion and tight connection.

#4 Cougar


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Posted 17 March 2013 - 09:54 AM

Someone else here had a similar problem recently. The grounds should be at the rear of the engine at the top.

#5 torxxx


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Posted 17 March 2013 - 12:02 PM

ground from the tranny to the firewall, battery to bellhousing, and then there is 2 grounds one on each side of the frame rails right in front of the valve covers (only certain years of the Gen 3 Legacy had them, I dont remember the specific years but they will be 10mm bolts if yours has that style grounds in that location)

#6 idosubaru


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Posted 17 March 2013 - 01:36 PM

a "solution" can end up being an artifact of the intermittent nature of the problem.  verifying ground is a fantastic idea but i wouldn't necessarily have all my eggs in that basket depending how many times/how notable that test was.

did you try removing the cables as soon as it "ran better"?

did it immediately go back to running bad?


wrong engine but the H6 00-04 engines have common TPS issues, by far the sensor with the most issues.


4 cylinder TPS issues are rare and used is a great option over the over-priced new.


a guy on another subaru forum disassembled an older TPS and cleaned the contacts and he said it notably smoothed everything out.

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