P0446 P1124 P1126 CEL Lights

[HELLAS59]

Hello Everyone.

I have a 1999 Boxster Tiptronic Base Model with the codes mentioned in the title. I am not very Mech Savvy which is why I am asking for you good folks to give me some guidance on these problems. I recently took the car to a nearby mechanic and he told me that I need to replace the Catalytic Converter (I ve had a really loud rattle for some time now) as well as a crank sensor that I am not familiar with. I guess my question is: can these codes P0446 P1124 P1126 be caused by the problems mentioned by my mechanic? Ive read that those codes most likely indicate an Air Leak, a bad AOS, dirty fuel injectors, and a few other reasons. I was quoted a bill of over $1700 to fix both problems. And if my Cat is rattling, does it necessarily mean that I need to replace the whole thing? If so, I have read online that the best route would be to buy used OEM. Any feedback/help would be greatly appreciated my brothers.

[JFP in PA]

More to the point, it looks more like you may need to replace your mechanic,

First of all, there are a lot of thing on the exhaust, like multiple heat shields that are famous for coming loose and rattling, so I would not immediately start thinking about replacing the expensive cat until appropriate diagnostics say you actually need one.

As for the codes, P0446 points to a problem with the EVAP canister shut off valve on the intake purge line, which could also cause a vacuum leak. P1124 and 1126 are both O2 sensor codes that indicate that your intake system (which is attached to the EVAP purge line) has a vacuum leak because the DME cannot enrich the mixture enough to get the fuel air ratio back in spec. None of this points to bad cats, just a problem valve and possible resulting air leak, and some otherwise poorly executed diagnostics.

[HELLAS59]

Thank you so much JFP for the quick reply. I may need to complain to him about the route he chose on diagnosing these problems. He seems to be a very reputable mechanic that works on a lot of Germanics as well. Nevertheless, I received the complete writeup from my mechanic and a Diagnosis Bill of $150 so that he could tell me about my P0446 P1124 P1126 CEL codes with written descriptions of each code. (Things I had already looked up online).

He listed the parts that need to be replaced which were:

*Converter, Exhaust Catalytic (Drivers Side).

*Sensor, Crankshaft Position

NOTE: No smoke tests were performed for Vacuum leaks. The Evap Canister was only mentioned in the writeup as one of the codes (P0446) that showed up and was listed as being: "Below Limit".

He also mentioned that the Drivers Side Cat seems to have been welded around the area that it has currently broken from, something that the previous owner must have done. (It lasted 7 years whatever he did).

A total of $1700 for the Bill...way too much I believe, especially for things that may not actually fix the root of the CEL codes problems.

Did I just get ripped off? What should my course of action be? Please my friends...any advice would be greatly appreciated !!

God Bless you all.

[Jamesp]

After reading JFP in PA's reply, you don't need to go back to the last mechanic to complain or try to get your car fixed. Take JFP's advice, cut your losses and find a new mechanic.

[HELLAS59]

I agree JamesP. I cant believe he didnt even attempt a smoke test? I learned about it too late while researching about these codes and didnt get a chance to ask him to perform one as I thought that he would know since he is the professional. I just took off the oil cap while the car was running and it came off fairly easy, the idle changed as well which (Ive read) usually means that the crankcase vacuum is good? Would you guys say that this is a pretty reliable method for the elimination purposes? Should I proceed in attempting to do the same test for the intake manifold vacuum by pulling out a hose from the AOS ? Would a smoke test be the most ideal place to start ?

[Swhitcomb]

Originally Posted by Jamesp

After reading JFP in PA's reply, you don't need to go back to the last mechanic to complain or try to get your car fixed. Take JFP's advice, cut your losses and find a new mechanic.

I would strongly suggest taking the car to Chapman Auto Werks in Sterling VA. Porsches are all he does, and he does them well. They are very versed in M96 engines. He did an excellent job on my car.

[Jamesp]

Unless you're going to do this yourself, give it to a mechanic with a smoke machine, let the mechanic know a vacuum leak is suspected, and it should be easy to determine if there is a leak.

[Swhitcomb]

Chapman Auto Werks - Home

Tell him I sent you.

[Toppy986]

I think i can finally claim to have fixed my cel issue, i was getting P1124 and P1126, i would clean the throttle body, mass air flow sensor, tighten clamps, all the thing's one would do to try and fix these 2 code issues, all the time clearing the codes after every attempt. Nothing was working so i resigned to driving it for a while with the light on. My problem was that the evap system was the last system to reset, i finally got code P0446, this directed me to the evap purge valve, i first attempted to blow out the line, however the O2 codes came back rather quickly, after replacing the purge valve and driving 2000 code free miles i am claiming a successful repair. I couldn't have gotten there with out this forum.