My 2005 MCS is having a problem starting, a few nights ago I tried to start it the car turned over slow but started. The dash lights blinked, the parking lights flashed, and the SES light came on. The car ran fine. The next morning the car started fine and the SES light was out, later that night I try to start the car and the car does the same thing it did the night before. The next morning the car starts fine, but the SES light is still on and has been for two days. I took the car to Autozone to check the code, they showed one --P101F mass or volume air flow circuit range / performance. The way the car was starting I was expecting a battery problem. Has anyone had this problem or know of the fix? Any help would be great.

 

My service advisor told me that the codes AutoZone shows don't always match up to theirs. He told me to call him with the code and he can pull it on their system and transpose it. Anyway, I've read threads hear and there of similar issues and it seems to always point to the battery. How old is the battery? Do you have mods?

 

drsimmons, no mods car is stock and I don't know how old the battery is. I checked to see if a date was on battery but no luck. It is a mini battery so who knows if it has been replaced.

 

get the battery tested at autozone for free, but i suggest have it replace by dealership. I heard this car needs to be re-programmed after battery disconection, such us transmission and some other electrical accessories may not work properly after disconnecting the battery. let us know whats the result.

 

After buying my 07 MCS this past Aug. I figured the battery was a good 4 years old. Found out Mini batteries usually last a little longer but I changed it out anyways. Got one from O'Reilly's Auto Parts locally and it fit. Only thing I had to do after disconnect and connect is reset clock.
Everything else was fine.
Have it checked out first so you don't waste money on something you don't really need but I'll bet it's the battery.