sfirestine

Hi everyone. I'm pretty new to the forum, but not new to Porsches. I currently have a 2001 996 Cabrio that I've been doing some minor mods to. I put Fabspeed MaxFlo mufflers on, the K&N CAI, and then a Unichip. I did them all in stages to make sure each worked before the other. A few weeks after everything was installed, I got the dreaded CEL. I tried resetting the ecu, but the CEL came back so I removed the Unichip to see if that was causing any issues. The CEL again came back with the stock ECU so I took it to my local and very respected independent Porsche shop. They said the CEL code was that the left bank longterm was too lean and they reset it and said if it returns in 50-100 miles, it's likely the mods, specifically the intake.

However, here's where the fun starts. On the way home from the shop, the first time I got on it and went over 5 grand RPMs, the PSM Off and ABS lights came on and would not go out. I pulled off the road and shut it off and back on, and they stayed out until the next time I got above 5 grand or so RPMs. I tried disconnecting the battery just to see if it wasn't a glitch from resetting the CEL code, but it continues to happen everytime I go above the magic mark on the tach.

Sorry to be so long winded, but I wanted to include all the details I could. I'm baffled by this one and wanted to see if anyone has come across this, before I take it back to the shop for more money out of my pocket. Any help or ideas would be greatly appreciated! Thanks!

Bos

Happen to stumble across this thread... Sounds like the issue and was MAF related.

https://rennlist.com/forums/996-forum/287012-pse-off-and-abs-lights-come-on-under-wot.html

joes c4 cab

Sounds like MAF to me too - I had the same codes and after the bonehead changed all the O2 sensors, he figured out it must be the MAF. Buy the part and do it yourself. It is an easy install.

wross996tt

Yes that is typical of the POS MAF!

sfirestine

Excellent... sounds like the issue exactly. I'm going to try taking out the MAF and spraying some CRC Electronics cleaner on it and see what happens. Hopefully that's all it is. I called the local Porsche dealer to get their thoughts and they seemed to think it was a wheel speed sensor and were already talking $400+ to replace. If that ends up being what it is, I guess I'll have to go that route, but if it's just a dirty MAF, I would not be too happy to spend all that only to have the problem return on the drive home!

Thanks again... will keep you posted!

wross996tt

First did you ever get the codes read? If so what are they...we can help better knowing them. If you already got the ABS/PSM and a CEL the MAF is blown and no amount of cleaning will bring it back...sorry. Buy a new one ~$240 and install it yourself. Now why it blew...do you have stock intake and dry filter? If not I would suspect those items first.

CosmosC4S

Would someone please enlighten my amateur mind a little?
If the issue is with the MAF sensor(air intake), why did the ABS/PSM (brakes/wheels) lights come on?

wross996tt

Perhaps you should contact Porsche directly for the answer to this bizarre event. Unfortunately it is what it is. Read the codes!

Bos

Translation... Knowledge is power: You will be in a much better position for receiving relevant answers from the forum with the ODBII decoding information. Not to mention, positioning and perspective with the dealer.

Just one "newbie" to another....

sfirestine

Well I disconnected the battery, took out the MAF tonight and cleaned it good with the electronics cleaner. I also cleaned all the contacts on the plug connectors as well. Took it out for a drive and it all looked like it was going to be good... couple hard pulls past 5 grand and no lights. Then on about the 4th hard pull in 3rd gear, just past 5 grand and there come on the lights again.

I guess at this point either the oil from the K&N filter is getting on it and triggering the lights, or the MAF is shot. Do you think the dealer could have a point as well with the possibility of a bad wheel speed sensor? It just seems odd that this seems to be a common issue with those who've installed the K&N CAI. I guess I should have just stuck with the darn EVO one. Oh well, you live and you learn...

Has anyone tried another cone style, non-oiled filter on their K&N kit, to see what effect that had on the situation? I'm thinking of trying that out as well.

Wross, as for the codes, I did not get the actual codes back from my independent shop. All they told me was that the code meant that the "long term fuel trim bank 1 system was too lean." Sorry, I didn't think to ask for the code since they said to see if it came back in 50-100 miles. If it CELs again, I'll get the codes from the AutoEnginuity I just ordered and check here first before going to the shop!

wross996tt

I'd say it is not the wheel speed sonsor. It is a blown MAF (cleaning will not fix as I said already!). Get a new MAF and then decide if you want to stay with the upgraded intake or back to stock...either way I think dry filter will be a better choice.

You can order MAFs here. Easy DIY install.

http://www.autohausaz.com/search/pro...0Mass%20Sensor

CosmosC4S

I'd be damn...but thanks for the tip.
I'm learning...I'm learning...

The E39 BMW's have the same CEL realated to faulty MAF sensors as well.
I wasted money on several unrelated parts, stressed out with the lights coming on again,
finally I got some recommendations from the BMW forums and suggested to my mechanic before he tried borrowing one from another 540i that happened to be there in the shop and it worked.

Funny thing is...the brand new MAF sensor that was installed failed on my way home from the shop! I was pulling out off an exit onto the highway and floored it....the whole engine just cut off. I was already in the fast lane, so I had to roll over onto the median. Replaced with another brand new one and never had problem since.

TT Surgeon

The ABS and PSM are more than likely a brake or wheel speed sensor,(esp if in combo) probably unrelated to the CEL or other mods unless the operating temp was excessive. Check under the front axel assembly with the car jacked up, see if something is dragging behind the rotor area, this is where the two sensors are located. Then check the sensor with a resistance probe, should read 1.0-1.5volts with a complete revolution of each wheel/rotor. Any decent indy should be able to do this for you if you're not mechanically inclined.
C

RJMDAD996

It is the MAF - I just changed to the K&N Cold Intake and BAM ! now I get the same Errors - Without a doubt it is the MAF !

yvesatlanta

Yup, same over here. I have the K&N cold air intake.

What I wonder though, is it really necessary to toss in a new MAF ?
Could this in any way harm the engine, or is it just a warning light triggered by the fact that the MAF is now operating in a non stock environment ?
Also, is this something that's going to continue to happen as long as we keep the K&N filters ? In that case we better start ordering new MAFs in bulk...or return the K&N filter. Seems to be they have not performed approriate R&D on this unit.