How many times can you get the same CEL?

[babur]

I know that there are few threads regarding this issue but hopefully this is a little new... At start up, I've had quite a bit of smoke but went away after a few sec. But later, it started smoking like crazy (though would stop after 10-15 sec). The next day, when I was taking it to the mechanic, the car stalled and had to tow it. There was almost no oil left in the car! Clearly, it was the AOS. Of course, with all the tubes being brittle near the AOS, I had to pay $800 to replace the AOS and tubes, etc. Fine! At least the engine was not hydrolocked! I was happy that I got my car back but after driving may be 40 miles, when I came to a stop sign, I've had the same P1128 and P1130 I had before the smoke!!! I also noticed a hissing sound coming from the driver's side, like air is coming out of a tube. Other than that, it drives fine and there is no smoke whatsoever.

Why would I have the same codes again? Is the ECU still trying to learn the new data? Or may be the mechanic did not properly put one of the hoses or something like that?

Any insight would be greatly appreciated.

Thanks

Bob

[crod]

These codes are usually associated with O2 sensors and the MAF. But the hissing sound could be some air leak, what can indeed trigger the codes mentioned.
So when you get the car back to the mechanic, make sure you check what I mentioned above.
Note I am no mechanic, just a Boxster owner like you.
Comments from way more experienced owners are appreciated!

CR

[Lobo1186]

if tubes got messed with i would definitely say air leak especially with a hissing sound. seems the best place to start

[landrovered]

EFI codes can be incedent type or a state type. For example a cylinder misfire code can register twenty times. An O2 sensor code will generally register once and then the ECU will change states as the result of the code. Like going into limp home mode. So the answer depends on the code that is being thrown.

[mikefocke]

and any other problems the original problem caused.

So assuming the AOS was the problem, did the AOS replacement guy also clean the intake tubes and the throttle body? If he did, could have left an air leak. If he didn't, could be residual oil from the AOS failure so do the intake and throttle body cleaning. Link

[JFP in PA]

You will continue to get the same CEL codes untill the problem is isolated and properly repaired, and the code is cleared...............

[Viper5]

I had almost the exact same problem as you and I'm pretty sure I had those codes as well. I could not figure out for the life of me what it was. Stealership told me that my AOS was bad because hewas using some tester device and thats why the code was popping up. I replaced AOS and in the process, busted the y-tube. Well, it was $25 and a lesson well learned. As for the AOS, that cost me about $150 if I remember correctly. Still got the code. At this point I was getting really frustrated and I found out that if it was an air leak, then it would be difficult to find. So I went back, and they were able to tell me where it was. Sure enough, I had a leak in my broken brake booster hose (the one towards the front of the engine with the crescent white piece to lock it in). Spent another $40 or so and problem fixed. Whatever code I was getting, it had something to do with idling higher than normal which it was actually doing. After the replacement of the hose, it was fixed.

[Topless]

The codes mean your car is running lean. Lean mixture codes plus hissing sound? Intake air leak 90% of the time.

[babur]

OK! I visually inspected the hoses this weekend and they seemed all right. Cleaned the bottom of the air (engine) filter housing as there was still tiny bit of oil left.
This morning is the first time I drove the car after resetting the codes. My commute is about 25 miles and no CEL yet! But the hissing sound is still there and idling funny. When I called the mechanic and told him what's going on, he said it could be the MAF or even the spark plugs because there might still be some oil residue (and that may be why it is idling funny - don't know).
I will take the car on Friday and we'll see. But I assume it's the intake air leak because he needed to move things around when he changed the hoses.
BTW, he had cleaned the intake tubes and throttle body.
So I keep my fingers crossed and let you guys know.
Thanks for all the help.
Bob

[babur]

Darn! CEL came back on! What a suprise! But this time, I can feel the loss of power and a little rough idle!
The mechanic who changed the AOS said that he cleaned the MAF and throttle body. But again, the car was burning so much oil that I am wondering if it messed up the MAF and/or spark plugs. Is it possible? Just to put in perspective, before the car stalled on the highway, my oil gauge showed full and "below min" and blinking after it stalled!
Thanks
Bob

[Topless]

If your CEL error codes are still P1128 & P1130 your car is still running lean. This means a failed MAF or intake air leak. A hissing sound points to an intake air leak as the most likely cause for your problem. If your mechanic does not recognize this or believes that changing spark plugs will somehow resolve a lean mixture condition... get a new Porsche mechanic.

Troubleshooting and diagnosis requires the simple process of elimination. List all the possible causes, one by one eliminate each starting with the most likely cause. This works every time.
1. Bad MAF- unplug your MAF and drive the car. If it runs much better, replace the MAF.
2. Torn intake hoses- inspect one by one and replace as needed.
3. Loose hose clamps- inspect and tighten.
4. Torn AOS Bellows- replace
5. Cracked oil fill tube- replace
6. Bad gas cap- replace

And so on and so on.

If it were my car I would begin by opening up the engine cover, start the car and just listen/poke around for the hissing sound. Some will use propane to identify an intake air leak but I totally singed my eyebrows once with a propane flash fire so I am not a big fan of this method. Maybe just a loose hose clamp. No reason to get hosed with unnecessary repair charges.

Get your error codes first to confirm the problem and then proceed. Good luck!

[mptoledo]

I noticed that I get an o2 code when I use the fuel additive. I think its the chevron techron. I usually just disconnect the battery and don't see it for 3 months when I do it again. It usually happens when the engine is hot after driving for a few hours and the tank is close to 1/4. I had the codes checked twice but noticed that it happened after I filled up and added the techron.