: on again off again CEL

10-09-10, 06:48 PM
My CEL is playing on again off again with me. About 4 weeks ago my CEL came on. I called onstar and they said it was "cat convertor low effiency,bank 2. That lasted for about a week and then it mysteriously disappeared so I called onstar again and they said there were no codes showing and no codes were stored. That lasted for about a week and a half, then all of a sudden the CEL came back on and it lasted for about another week and onstar said it was the same thing all over again, then again it mysteriuosly played the great dissappearing act once more and onstar said no codes showing and none stored. This problem is playing musical chairs with my feeling. When I get ready to take it in it goes away. I am at my wits end. Any ideas whats going on here or if anyone else is experiencing this problem?

10-09-10, 06:58 PM
Sounds like your cat is marginal. Are you within the Emissions Warranty?

I doubt Onstar can be as thorough as a dealer code check. Am I thniking of another member that had a dealer look at a similar issue?

10-10-10, 01:48 AM
I have 64k miles on my whip and everytime I make an appointment the CEL clears before I have a chance to bring it in. If I bring it in without the CEL on, they will tell me that they can't replicate the problem an nothing will be done except to take my money and my dealer charges $159 to diagnose. When the light comes on I feel no loss in performance or anything. I will keep my eyes open and hope one time it comes on that I can get it to the dealer before it clears itself.

11-11-10, 04:50 PM
The thing is when you bring it in and the lights not on, the car stores those codes and it knows how the car was running, mph, and all of that. Its called freeze frames, so dont let the dealer fill you with a bunch of b.s

11-11-10, 09:07 PM
Just make sure you report any/all trouble while under warranty and you have recourse even if some dealer doesn't want to 'deal with it'. GM's zone managers will honor claims when properly documented.

12-06-10, 11:30 AM
UPDATE: I finally got the chance to have my STS looked at on Friday when I took my car in for an oil change. The CAT'S were checked and they were bad ( as if I didn't know?) and the dealer also said that I needed a motor mount on the right side so this Friday after the parts come in I will have this work done. I will let forum members know the damage report when all work gets done.

12-07-10, 10:25 PM
addemdum: by the way i'm only getting 12.31 miles per gallon since my cats went bad and when it is repaired i will have another calculation made an hope my mileage gets better.

12-08-10, 05:10 PM
Unless its 2017 or his car has 200k its under warranty, GM extended the Cat warranty on all 2004-2005 SRX and 2005 STS with V8 only to 12 yr 200k miles...

12-08-10, 09:25 PM
Unless its 2017 or his car has 200k its under warranty, GM extended the Cat warranty on all 2004-2005 SRX and 2005 STS with V8 only to 12 yr 200k miles...
That is correct, I got the letter from GM last month.

12-10-10, 04:54 PM
Well this is how the story goes: The Cat was replaced along with the left motor mount. I also got another surprise from the dealer. They informed me that my transfer case was bad. So here we go again. The STS saga continues. Thank God for my bumper to bumper extended warranty. I'm getting it done the first of the new year because the dealer said they will have it for about a week and they are slam packed for the next 2 weeks. They said they had to tear it down for the warranty company and then repair it after they get the ok and that will take approx a week but I have a free loaner with the warranty so I shouldn't be in to bad shape. Last time I got a DTS....Not bad heh! I will update when it's repaired.