Cadillac DTS Forum - 2006 through 2012 Discussion, Check Engine Light-O2 sensor in Past Cadillac Vehicle Discussion; I just bought my DTS 06 in April for the last three months the check engine lights comes on and ...
I just bought my DTS 06 in April for the last three months the check engine lights comes on and throws an Oxygen Sensor code. It stays on for a few days and goes off. I had all three sensors replaced and two weeks later it came back on. I took it to the dealer and they could not figure it out why it comes on and goes off. They checked the sensors and they are testing fine. I love my car but if I can't figure this out I would have to think about getting rid of it.
I don't know if my experience was the same as yours or not. My '06 Performance was throwing P0420 codes in much the same fashion as yours. It would go on for a week or two and then go off for a week or two. The P0420 code is for low cat efficiency, which could also be set off by a bad o2 sensor. Seeing that there were no other symptoms, and since I was somehow convinced that this was a false code, I decided not to have the cats replaced at almost $1,000 as the dealer suggested. I did some research and found out that there had been a service bulletin released addressing this particular false code, and that there was a software upgrade to fix it.
The next time I had it in for an oil change I had them perform the $122 upgrade on the chance that it would cure the problem. It has now been 4,000 miles since they upgraded the softwase and the SES has not come back.
What bothers me is that the dealer, a 5-Star dealer that constantly wins service awards suggested the cat replacement, and would have been happy to do the work, probably upgrading the software while they did, until I presented them with the information on the service bulletin. I had been talking to them about this issue for a couple months and they never brought the TSB to my attention, yet when I finally told them to go ahead and do the update, the service writer told me that in most cases it fixes the problem. Clearly, they were aware or the issue, but wanted to write a ticket for $1,000 instead of one for $122.
Again, I don't know how this may or may not relate to your issue, but in any case do your homework. It could save you a bundle.
I just spent the last hour or so reading up on the P2A03 code.
That was a new one, that I hadn't seen before.
Seems like it can be caused by a dirty MAF, a bad or leaking Catalytic Converter or by an exhaust leak.
Do you have any exhaust leaks... even a tiny one appears to be able to cause this code.
I have an 06 dts performance as well and ive been experience this same issue. One day my oil pressure light came on after they fixed my water pump and they
wouldnt return the car to me until the light went off. my oil pressure was fine and the issue was the wires to the oil pressure sensor was close to the exhaust or tuching which caused the wire to be to hot which resulted in the car getting a faulty code. when they moved the wires the oxygen sensor code(check engine light) went of as well. it comes on and off but i believe that is the problem. I plain on fixing this soon so ill share my results with you guys.