Hello Mafia,

I am a long time member who NEVER posts, but I do lurk and read a ton of info on this forum. I hope to contribute more in the future....

I am a pretty experienced hack mechanic and have been trying to trouble shoot an issue on my 03 Mystic ZHP sedan. I recently changed out the DISA, Cleaned the ICV and MAF and replaced the CCV with the foam coated cold weather pieces. I was having much complained about cold weather rough idle start conditions... After much internet research and tearing the whole thing apart I found that the lower CCV drain hose to the oil pan was not fully seated and creating a vacuum leak. I replaced it and have had a perfect idle at start up ever since no matter how cold or long the car has sat. (I also cleaned out the dipstick tube where yellow sludge can accumulate at the bottom of the CCV drain hose)

The issue I am now facing may be related. Twice since I performed all the work my car has gone in to limp mode while driving. Both times I was able to pull over and restart the car by turning off the HVAC system and then cycling power with the key to position 2 and off. It is mind boggling to me how the HVAC system could be causing my car to go in to EML mode. A little history.... I have replaced the battery several times in my car since purchasing it in 2006. I did some research years ago and found internet info about a parasitic draw from HVAC (FSR), but my car did not exhibit any of the fluctuating fan speed or post shutdown continuous fan symptoms so I never replaced the FSR. I did however start using a tip that I found which was to simply "reset" the car by turning the key to position 2 without starting every time I shut the car down. This has magically helped me to keep my battery charged for several years without replacement. But now I am experiencing the EML issue which is very sporadic. As I mentioned earlier I believe the HVAC is part of my problem as both times I have gone in to EML mode I have had to shutdown the HVAC system in order to cycle power and get the car running normally again. Is this just a coincidence? Has anyone ever experienced this before? Note that the first time this happened I cranked the heat after a cold day on the golf course and the car went in to EML mode at about 35MPH after 10-15 minutes of driving. The second time the car went in to EML mode I had the AC on fairly cold and was stopped at a traffic light with the car idling in 80 degree heat outside.

I pulled codes after the first heat on/ cold day EML issue but have not had a chance to pull codes again after the more recent warm day A/C issue. All I got was some mis-fire codes.

I have read that there is a known issue with HVAC programming that can be re-flashed by the dealer. If anyone knows anything about this, please arm me with info before I walk in to the dealer with a Mystery problem that they will surely take advantage of...

Thanks much!

On a side note I am more than happy to help ZHP owners in the DC area (Northern VA specifically) with garage work space, tools, lift and an extra set of hands for less than 1 day projects at my home if needed.