What engine do you have in the Vitara - a 2003 could be a 1.6 or a 2.0?
Does the engine shut off - or - does it stall - which is it?

These are actually two different symptoms which point to different causes - if you hold the throttle open - to say 1500 rpm (or if you're driving) and you switch on the a/c - what happens?

Does the engine die? You probably have an electrical issue.
Does the engine continue to run? I would suspect the IAC (idle air control)motor, although there are other possiblities.

Switching on the a/c increases the load on the engine from two sources - there is a/c compressor load, and increased electrical load from the evaporator & condensor fans - the increased load cause the idle rpm to decrease and the ECU compensates by allowing more air flow through the idle air control - if this fails it may not set a code.

 

Thanks Fordem for all the good info. It is a 2.0 engine and the engine will cut off when idling after turning on the a/c, but while driving the rpm will just drop but continue running. I will check what you suggested this week.
Thanks again.
mklaw

 

Does the a/c work - as in cool?

If you can detect a drop in rpm when you switch on the a/c whilst driving, it would suggest an abnormal load.

 

Yes, the ac is working.

 

Perhaps try getting the O2 sensor problem fixed first? The front O2 sensor would be the one the engine uses to control the mixtures so it might be part of the problem.

If that doesn't help then investigate the IAC as mentioned earlier. They often get clogged up with carbon etc and simply need a clean with carby cleaner (or a similar product.)

 

Will do. I was thinking the same thing concerning the O2 sensor.
Thanks for your input.