Cadillac STS Forum - 2005 through 2012 Discussion, Need help with Check Engine Light in Past Cadillac Vehicle Discussion; Check Engine light comes on and goes off by itself and sometimes it goes a week before it comes back ...
Check Engine light comes on and goes off by itself and sometimes it goes a week before it comes back on for a few days before it goes back off again. Car still rides fine and I have not noticed any performance changes.
Pulled out a scanner and I have the following 4 codes:
Any idea where I should start? Based on some Google searches it seems to be vacuum leaks or a MAF malfunction. Also seen some threads where it said ECM needed to be reprogrammed.
I had the same problem. I checked the intake manifold bolts and they were loose. After tightening them I removed the MAF sensor, cleaned it in ethyl alcohol, rinsed it in hot water, and dryed it with a hair dryer. The problem has never returned.
And sure enough I removed the engine cover and at least 6 bolts were loose on the manifolds that I could turn by hand. Tightened all of them and will see if it comes back before I remove the MAF. Thanks!
2004-2006 Cadillac SRX, XLR
2005-2006 Cadillac STS
Equipped with Engine RPO LH2
Please Refer to GMVIS
This bulletin is being revised to change the labor time information. Please discard Corporate Bulletin Number 09-06-04-032 (06 - Engine/Propulsion System)
Some customers may comment on an illuminated check engine light shortly after a cold start with no engine performance concerns. Upon inspection, DTC P1101 (Intake Air Flow System Performance) may be set. In some instances, DTCs P0068 (Throttle Body Airflow Performance), P0171 (Fuel Trim System Lean Bank 1) and/or P0174 (Fuel Trim System Lean Bank 2) may eventually set as a result of the DTC P1101.
Verify the condition. If the diagnostics in SI for the conditions described above do not isolate a fault, reprogram the ECM with the revised calibration that has been developed to address this condition.
Verify that the multiple diagnostic interface (MDI) that is being used is configured to the PC that will be used.
((Table is not here, I couldnt copy and paste it, it says .4 hours labor.))
For vehicles reprogrammed under the 8 year/80,000 mile (130,000 km) emission controller warranty, use the table above.
My car only has 60k miles but since mine is a 2005 I guess this falls out of the warranty. What is this going to cost me?
Ethyl alcohol = ethanol = either cheap 100 proof vodka or grain alcohol at a whiskey store.
The ONLY reason you cannot drink 190 proof ethanol designed for gasoline additive use is that it is "denatured" - rendered unfit for human consumption - by the addition of stinky chemicals or just plain old gasoline.
If you were to take pure ethanol from a distillery on Monday and age it for 7 years in charred oak casks you would wind up with bourbon. Take Tuesday's output and add a denaturant and you have gasoline additive. (Simplistic, but the basic premise holds true)
When is the last time the throttle body was cleaned? It seems to me that the codes you have indicate a mismatch between what the MAF senses for airflow and the physical position of the throttle. At its worst, I could restart mine three time and the code would clear.
I'm working in a shop and we have a 2003 STS in with a P0102 Mass Air Flow (MAF) Circuit Low Input. The boss pulled the intake off and cleaned the throttle body as well as the MAF, and it"s still throwing us the same code.
With a scan tool such as the Autoenginuity you can read out the MAF signals as well as throttle position and other data and compare it with expected outputs as outlined in the factory service manual. Otherwise you might as well be another amateur floundering around with guesswork.