P1117, P1121, Po131, Po151, Po137, Po157
 

Well, this could very well be my first post on the 986 Forum! Nothing like an introduction with problems. :rolleyes:

I picked up my 3rd 986 a couple of weeks ago. Been struggling with this one a little. MAF is 3 years old, cleaned it with warm water.

O2's are about 1 year old, I did replace one of them, all codes remain.

I've been checking the harness, cannot find any broken or shorted wires, but I'm still working on that.

Any other places to start looking?

Replace the MAF anyway? I ordred my OBDII cable so I can run the datalog. That'll help as well.

Thanks for any help,
Dan

Welcome to the Forum! :cheers:
And sorry you are already having problems. I don't mean to split hairs, but you said the error codes "remain". Did you reset the error codes after cleaning the sensors? The codes will not go away automatically once you fix it, you have to reset and see if it comes back.

Thanks for the welcome Rick.

Yes, I did clear the codes after each trial. First was the PO151 O2 sensor for a new one. Cleared codes, came back after that 10-15 minutes of driving. Next was really checking as much as I could for harnes failure, air filter is very clean, washed MAF with warm water, let dry, cleared codes, came back same amount of time and same codes.

This is my 3rd Boxster and I have a data logger, but my buddy lost the cable. I have another cable on order now.

Cats have 100k miles on them......but you'd think I'd be pulling the high temp on the O2's, not the low temp?

Plugs and terminals look clean.

Could be a MAF still?
Oil seperator?

I also have my brake wear light on with 4 new sensors. I'm a little concerned there is a harnes issue. I haven't checked it all for sure, only a few parts that pass through something. I'm hoping someone else has had this failure and can chime in with some good ideas where to keep looking.

-Dan

Year, model, and mileage?

Those are not mixture codes that indicate a bad MAF. More likely:
1. Water damage to harness or DME.
2. Rodent chewed/damaged harness.
3. Wrong O2 sensors for car.

Oh, sorry about that.

1997 2.5 5spd, no TC and no mods.

Yuck:

"A contact at BOSCH who make the sensors for Porsche admitted to me that there are differences (even though the part numbers are the same!) between the ones sold in the aftermarket in BOSCH boxes and the ones sold to Porsche in Porsche boxes or bags. A genuine sensor from Porsche costs between £300 and £500 depending on the engine model, and the Bosch ones are much cheaper. However, the Bosch items tend not to last as long, are made/calibrated to lower spec's and fail much sooner than the Genuine parts. Its even been said that the ones sold in Bosch boxes are often ones which have failed Porsche quality assurance testing. Also a Genuine item comes with a 2 year garauntee from Porsche, even if installed by an independent specialist."

I am starting to think this is my issue. Mine is over 30k miles old. I'll have to check the reciept.

After lots and lots of reading (I should be working) I've ordered a Bosch MAF, not the dealer one for $707, but one from parts store for $162. The dealer price of $707 is a little hard to swallow.

Seems my issues combined are pointing towards a failed or failing MAF. The ABS light along with the CEL codes certainly support this theory. I'll keep updates coming here.

Although the rodent or water theories carry a lot of merit. I'll start checking those as well.

Dan

Hey root,

Since you are in Seattle, next time you need OEM parts, talk to: http://www.****************************************************.com/

Pretty much everything I've ordered from them is half the price of Barrier. Last I checked Barrier charged 30% over the "list" price, and Sunset is way under list. Plus since they are in Oregon it only takes a day or two for stuff to show up UPS ground.

-james

Thanks! It's been years since I've had a WorldPac account so this helps a lot. :cheers:

New cable arrived:
 

I am using OBD-2 software which only has VW-Audi level codes beyond standard OBD2 codes.

Hooked it up, yup, all codes present, cleared them and ran a test on the O2's, they all passed.

I'll update when I get my MAF, re-clear codes and drive, log data.

Anyone have any other OBD2 software they could recomend?

New MAF installed today, cleared codes, 5 minutes into the drive they all came back. :(

Going to start looking deeper into the harnes.

I'll start with the DME next. I'll do some searching, it's under the pass seat? I'll look and see where it is.

-Dan

I am only someone who has little true knowledge but two things stick out. One, couldn't water getting into the electrical system via cleaning the MAF with water be a place to start and , two- I have had repeating codes that would occur when I was trying to sort out a problem and they never came on in 5 minutes of driving. I thought it would have to go through a certain # of drive cycles. I have tried to locate problems, clear the codes, drove it once and when I got back I would read pending coded. It would not as yet show up as a CEL but it was logged in. The short version is that it might be a DME problem. Ed

I took a look at the DME box today and cannot find any indication of water damage. I know it doesn't mean there isn't any or the DME box doesn't have issues, but it did make me happy everything around the DME and inside the rear trunk is really, really clean and no signs of water. I did remove it and plugged it back in some 30 minutes later. I haven't driven the car again yet, but I believe that resest codes by removing power from the box. Mostly I wanted to reseat the main DME connection. I'll drive and report back.

Re-seating the DME didn't do anything.

There are a couple DME units for sale, $200-300. I certainly don't mind paying for one, but the dealer asspect worries me a little. How much could they charge for re-coding it to match the car? Yuck.

I'll keep posting findings, or lack of. ;)

If your car is running well and no CEL with codes just drive the car to see if they re-appear. The DME is just a computer and like any computer it may go bezerk if water temporarily shorted your O2 sensor wires, but as it dries out it may be fine. Your unplug and reset may be all that was needed. You had several "short to ground" codes so water is a likely source of the problem.

The CEL did come back on after about 10 or so minutes of driving. I'll keep checking and posting updates.

I worry about the water damage, although I haven't found any evidence of it, I know it could be there.

-Dan

On my way into work this morning I noticed the CEL went out for a second, or part of a second, then back on. I've researched a little about bad grounds being issues. I've already cleaned the two back by the DME in the rear trunk, but know there is possible issues that might be coming from chassis to engine/trans. So I'll check those this week. I didn't have time this weekend to do anything to the little guy. I'll keep any updates posted as I can.

I'm still not ruling out a failed DME unit. I know capacitors can leak messing all sorts of things up. I'd rather not get another used DME unit. I sense frustrating times getting the immobilize-er(spelling?) re-coding done. Does anyone know of a place that rebuilds units? I don't mind having my Box out of service while the DME unit is rebuilt.

-Dan

This place advertises in PCNA Panorama magazine:

PorscheDME.com

Ad says they rebuild all DMEs including Boxster. For '97s they repair yours for $675 or sell on exchange for $975. Spendy. Yikes.

Vertex (****************************************.com) offers rebuilt ones for $299-$759, no details listed on their site. Based on my experience with their customer "service" and feedback I've gotten from people in the know about their remanufactured mechanical/electrical parts, I'd try the guys above first. I like to go with specialists for that kind of stuff anyway.

Thanks for the DME tip, I did find the website, yes, pricey, but 5 year warranty. Hopefully it isn't a DME unit.

I am running the CarCode OBD2 software which really isn't good for much of anything other than pulling the codes and clearing them. You can test the O2's which is nice, but I have noticed, the only O2 I can test is the one I replaced. Hmm, bank 1, position 1 is the pass, before cat right?

If that is true, maybe the 4 "new" ones installed just are not cutting mustard? I can smell it running rich at idle. Something isn't right. The one I did replace was direct fit Bosch from local parts store.