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Discussion Starter #1
I have a 2002 Outback 2.5L H4 Auto with approx 125k mi on the engine and 145kmi on the chassis and I am getting a p0172 Check Engine Light code - right bank rich -with intermittent symptoms: hesitation on cold warm up is the main one...have run several fuel ' injector cleaner treatments over the last 4500 mi and have switched to non-ethanol premium gas - both of which have temporarily resolved the symptoms and shut down the light...but now am getting a very small front crank seal oil leak.... the dealer in Boise will charge $50 to run down the diagnostic check on the code and said they could pinpoint the faulty part, which, when diagnosed with a non-dealer device reveals several possible culprits. Looks like I will have to do a timing belt/front crank seal replacement...the H20 pump only has 50k mi on it, but will probably replace that too?

Does anybody know if the dealer's claim is valid, as if it is, I'll drive the 200 mi and pick up the part...but I'd rather not roll the dice if the service desk isn't being completely forthcoming.

Thanks.

Any references on best place for parts source?
 

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With the right equipment it might be possible to narrow down the cause of the P0172. The Subaru Select Monitor is probably what the dealer would use; however, there are other similar devices ("scanners") that, while expensive for the average DIYer, other shops might have.

Regardless of the device used, it won't make readings and pop up a window saying "change xxx" as if xxx is the precise reason for the problem. Instead, the equipment is more likely to display a number of selected parameters (sensor signals etc) and it's up to the mechanic to interpret them. So the key, whether at the dealer or another shop, is understanding what the data is indicating; in other words, the knowledge and skill of the person reading the information.

http://www.subaruoutback.org/forums/66-problems-maintenance/49537-p0420-diag.html?highlight=P0420+Diag is an example where a particular code, P0420, which is often used to justify changing the catalytic converter in the exhaust system, was found to be caused by something far simpler.
 

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if you're asking about on-line parts houses, I've done the most biz with subarugenuineparts.com (email Jamie through there for special/odd questions - they are a dealership)

I've ordered stuff from Fred Beans and from ebay and from RockAuto and even amazon.
 

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Discussion Starter #5
Thanks for the replies...at this point, I've done two non-dealer code diagnoses - both read the same code with the same series of possible "fixes", so I am ready to try a dealer diagnosis. If the dealer can pinpoint or target a specific part for replacement, I'll pick one up and give it a go...if not, well, I'll take that up with the service desk after the diagnosis. I'll pick up a new fuel filter and PCV valve just because they're probably due, and tackle the oil seal soon. If anyone else has had a p0172 code problem resolved, I'm still interested....
 

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T hink you should consider the plugs and wires. Though i don't know why you wouldn't get a misfire code, a misfiring cylinder could allow too much unburned fuel through. Might explain the poor idling and would be 'bank specific' I think. Soobs prefer NGK plugs and OEM (or, at least, parts store BEST wires)

but I suspect many problems could lead to the code you have.
 

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The ECM is reporting high fuel mixture in the exhaust. This can be caused by worn plugs not burning the mixture fully in the combustion, the AF sensor, the one one front of the CAT, is reporting false information, faulty thermostat or MAF.

Given your mileage, I would guess at worn plugs. When the plugs wear down the spark changes and reduces the ability for the burn in the combustion to occur effectively. Plugs are due every 60k for severe driving or 100k for average.

My next guess would be the thermostat is sticking partially or fully open not allowing the engine to come up to temperature. Where is your temp gauge residing after driving for a while? Thermostat life is on average 60-75k miles depending on average ambient temperatures.

Review your service records and go from there. If you are overdo for either, start there, clear the codes and see what happens.
 

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Discussion Starter #8
Thanks for the suggestions! Took the car to the dealer (Larry Miller, Boise) and went for the diagnostic check...which revealed that the ECM was due to have an update - from an A setting to an E setting...a "reflashing" of the software. The update cleared the CEL and the p0172 code (which was stored in its memory). The engine sat at idle for 5 min in the bay, and "data looks OK"... The suggestion was to drive the car and see if the CEL light comes on again...if so, the most likely culprit would be the A/F sensor, which I'll purchase if that CEL shows up again. I drove the car the 200 mi home and discovered that it was having some trouble idling in Drive...so I'm set to change out the Fuel filter and PCV valve and give it another go...if that doesn't resolve the idle issue, I'll be going back to the dealer for ... another ECM reset? In any case, the Service Dept there did a first rate job! Waived the diagnostic fee in lieu of the ECM reset charge ($69.30) and I was able to go into the bay and talk with the mechanic (Doug) who suggested that the oil leak under the timing cover was more likely due to a leaking crankcase access port plug (one on each side of the front bottom of the crankcase, to access the rod bearings on each bank) and may need a new washer seal.... Better than having to pull the front crank seal and not stop the leak. More to follow....
 

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Discussion Starter #9
Also, This engine has new plugs and wires 25K mi ago and the temp gauge seems to be consistently showing appropriate operating temp...although I'll put in a new thermostat when I replace the timing and accessory belts and water pump.
 

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Thanks for the suggestions! Took the car to the dealer (Larry Miller, Boise) and went for the diagnostic check...which revealed that the ECM was due to have an update - from an A setting to an E setting...a "reflashing" of the software. The update cleared the CEL and the p0172 code (which was stored in its memory). The engine sat at idle for 5 min in the bay, and "data looks OK"... The suggestion was to drive the car and see if the CEL light comes on again...if so, the most likely culprit would be the A/F sensor, which I'll purchase if that CEL shows up again. I drove the car the 200 mi home and discovered that it was having some trouble idling in Drive...so I'm set to change out the Fuel filter and PCV valve and give it another go...if that doesn't resolve the idle issue, I'll be going back to the dealer for ... another ECM reset? In any case, the Service Dept there did a first rate job! Waived the diagnostic fee in lieu of the ECM reset charge ($69.30) and I was able to go into the bay and talk with the mechanic (Doug) who suggested that the oil leak under the timing cover was more likely due to a leaking crankcase access port plug (one on each side of the front bottom of the crankcase, to access the rod bearings on each bank) and may need a new washer seal.... Better than having to pull the front crank seal and not stop the leak. More to follow....
Really???? Data looks okay but drive it and see if it comes back on???:gasp:

Who serviced your car?

I think the dealerships are so hard up for profit they may be hiring right out of shop class at the local high school for lunch money.:2cents:

If the car is indead running rich, try Sea Foam to clean the fuel and injectors.

If the AF sensor is reporting rich, then the ECM would reduce the fuel trim accordingly to bring it back to Stoich.

If after many tries at altering the fuel trim and it still sees a rich value, it sets the code.

So, look for loose or broken vacuum lines, listen for a "whistle" at idle and pull the plugs and see what color the tips are. Beyond that, you would need a scan tool to be able to see the data. It could be a fault in the AF sensor. Could also be crappy gas like Murphy.
 

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I drove the car the 200 mi home and discovered that it was having some trouble idling in Drive...so I'm set to change out the Fuel filter and PCV valve and give it another go...if that doesn't resolve the idle issue, I'll be going back to the dealer for ... another ECM reset?
OK, no more ecm reflashes for you; once you get updated you have the latest upgrade. The idle issue is because of the reflash; your car has forgotten how to idle properly and it will relearn it. This happens whenever you reflash or even reset the check engine light.
 

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Hey CARDOC...thanks for your thoughts...replaced the fuel filter and PCV valve (both overdue and in need of being replaced) and the idle-in-gear problem seems to have evaporated. Runs very well now and CEL has not reappeared. No vacuum lines amiss and have run nearly a quart of Lucas injector cleaner thru it in the last 12,000 mi, so I don't think I have a clogged injector...plus, I am running the highest octane non-ethanol fuel available short of aviation fuel, so I don't think it could be bad gas, all Murphy's aside. I think the Dealer did a pretty great job considering that I was very specific and had some previous data and experience to provide. The mechanic, Doug, definitely knew his way around the 2.5l H4 engine and was very forthcoming regarding the ECM. the code, the symptoms, the fixes I had already attempted and the oil leak.... I will not be surprised if the ECM reprogram fixes the CEL and related symptoms; if not, I at least have a secondary solution to consider, and one that was at the top of the list to begin with. I'll check back here and update the thread if anything changes...plus, I think I may need some suggestions with the access plug leak on the left bank side of the front crankcase. I'm ready to proceed with a timing belt kit/H2O pump service unless someone pops up with a better alternative.... I replaced the timing belt and pump 70k mi ago, so I guess the service is due anyway. What I am wondering is whether I should go ahead and replace the front crank seal, the cam seals, and the access plug washer seals at the same time - or, take the road that suggests 'if it ain't broke...' Thoughts?
 

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It's not maintenance for nothing. With high mileage, it is always a good idea to replace parts that are readily accessible when performing another service. Changing seals at the same time saves time and money. Same goes with the timing components. A timing belt kit from Gates is available which has the pulleys with it. Replace the thermostat also. It's attached to the pump anyway. Check the interior of the hoses while they are off. If you can rub the inside of the hose with your finger and feel a soft surface or some of the rubber comes off the hose, replace them. The average lifespan of a hose is 7 years.

Not replacing these parts can lead to a failure and potential damage. Why risk it?
 

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Discussion Starter #14
Thanks to Sackett & cardoc for the input. For the record, the idle problem post-ecm reflash and upgrade did in fact evaporate and I no longer have any idle problems. however, the CEL has reappeared and I will be getting a replacement A/F sensor along with a timing belt kit (complete with idler pulleys, H20 pump & tensioner), crank and cam seals and access port washer seals. Any other thoughts on things that ought to be included would be appreciated. Am considering getting the FreeSSM diagnostic software (know that I have to buy an access cable) to tap into the ECM & TCM settings...hoping that I will be able to check and reset the CEL once to A/F replacement is in. Am I being crazy?
 

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Nope. The more you know and understand your car, the better. It gets easier with time and experience as you learn how the electronics operate to control the mechanical along with how the mechanical effects the electronics. It will also help you to understand all us techies when we get overly specific in our explanations.

And you will learn something new everyday. Just pay attention to the car and listen when it cries for help.
 
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