Help with P1275 Error Code - 986 Forum - The Community for Porsche Boxster & Cayman Owners

edevlin · 03-30-2007, 09:32 AM

I have been trying to trouble shoot an error code that kicked in after I had 100-cell cats and 4-new oxygen sensors installed on the car. I just got the Durametric software package for reading codes which is great, but I am having trouble interperting the data. I get one code which is:

"P1275 Factory Default Code 16 Signal delay time for oxygen sensor aging bank 1"
When I scrolled through to look for relevent data for trouble-shooting, this is what I came up with:

Oxygen sensor voltage ahead/behind of cat converter bank 2 0.45/0.45

Oxygen sensor voltage ahead/behind of cat converter bank 1 0.45/0.45

Sensor signal period ahead of cat converter bank1/bank2 1.70 / 0.57

Mean amplitude behind cat converter bank1/bank2 0.160 / 0.125

Regulator delay behind cat converter bank1/bank2 1.27 / -0.03

Oxygen sensor resistance ahead/behind bank 1/ bank 2 0/0 0/0

Cat converter monitoring time bank1/bank 2 1/1 sec

Oxygen sensor bank 1/bank2 1.0%/1.0%

Oxygen sensor heat ahead/behind bank1/bank2 4.28/4.28 4.28/4.28

A little background: the 100-cell cats I had installed were used, but in good working order when removed from the original car.

We have double checked the connections to the oxygen sensors, they seem to be fine.

We replaced a cat on one side with a new unit still getting error code.

We have tried raising and lowering the oxygen sensors in the exhaust stream.

We moved the precat bung onto the header (previously was further downstream)

The shop that is doing most of the work setup another 2.7L 2000 car with the identical exhaust, intake and chip setup that I have and that car has never gotten any error codes.

I am wondering if it might be something with the mass air flow sensor, because when I read the P1275 code with a generic code reader, not the durametric, it says something about "air fuel mixture...." I forget the rest.

Any ideas would be greatly appreciated.

Ed

dcporsche99 · 03-30-2007, 10:16 AM

Wow Ed! To think that it may just be an MAF code.....that's already a lot of work that you guys have done! But, if it is just your MAF--that would better than driving around with an UNKNOWN CEL light. Anyway, I hope it works out to be just that! Thanks for the update.

derb · 03-30-2007, 10:37 AM

Regarding the code definition... http://www.kbmsystems.net/obd_fault_codes_ref.htm

P12xx is a code group for Fuel and Air Metering and Auxiliary Emission Controls codes. Porsche gets more specific with the 'xx' part.
Those generic scanners usually don't know Porsche specific codes.

I also have the Durametric software. It's pretty handy.

derb

RandallNeighbour · 03-30-2007, 02:04 PM

It just might be throwing a fault code in the O2 sensors from a MAF issue... doesn't seem logical since it's a computer, but the oxygen sensors and the MAF have a very close relationship.

My mechanic had his PST tool hooked up to my car to diagnose a CE light and it was an oxygen sensor. It was making the MAF read bad too and one might think the MAF was gone as well.

We replaced the O2 sensor and the MAF's readings started to stabilize and looked great.

So do have the MAF temporarily swapped out to see if it might be causing a sensor to throw a code. It's certainly worth a try.

edevlin · 03-30-2007, 02:55 PM

"So do have the MAF temporarily swapped out to see if it might be causing a sensor to throw a code. It's certainly worth a try."

Great suggestion, we are actually getting a replacement MAF sensor to do just that swap.

Ed

edevlin · 04-02-2007, 08:35 AM

"I saw your post on the 986 Forum but did not want to make a post. There is a really easy way to test the MAF sensor with the Durametric tool.

Start with the car at idle

Select Motronic 7.2

Select Actual Values

Pick RKAT Bank 1 and RKAT Bank 2 from the list

These values should be right around 0.00 but no higher then .10 or lower then -0.10 If the values are in the -.30 or lower then it is likely a MAF problem. If it is higher than .30 then it is likely a vacuum leak. The RKAT values the amount of correction that is occurring to the air fuel mixture at idle. If your RKAT values are about zero your MAF is probably fine.

Best Regards,

Durametric Software"

I just got this note from the folks at Durametric Software about me checking on my MAF. I went right out and followed their instructions and came up with these numbers:

Adaptation Range RKAT Bank 1 0.00

Adaptation Range RKAT Bank 2 0.38

These numbers would seem to indicate that the MAF is working fine, but there is likely a vacuum leak in my system. I am very impressed by the diagnostic power of this code reader and software package. It looks like it saved me swapping out MAF and such, highly recommended for Boxster owners that mess around with their cars.

Ed

:dance:

RandallNeighbour · 04-02-2007, 08:45 AM

Ed, I was thinking about buying the Durametric software until they hauled off and locked it down to being used on 2 or 3 cars only. That sucks. I can't help out a buddy troubleshoot a problem, and if I buy a couple of boxsters I have to buy the software all over again.

...edited additional note:

Durametric sells an "unlimited cars cable" for the software for $477 in addition to the software, but said they'd be happy to clear out the 3 cars I might put on the software (or is it the hardware) for free by sending it back to them.

Sounds like these are good people to work with.