03 GT shuts off while on the brake


Jan 29, 2009
Burlington, NC
I have an 03 GT that just started cutting off when I was coming to a stop. I had a code for IAC so it was replaced. I went through all the relearn procedures and it was good for a few days now it just cuts off while on the brake when I’m coming to a stop. I also noticed my A/C is not working anymore either. There are no codes or cel on. Anyone ever experience this? Any help Is appreciated.
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SN Certified Technician
Aug 14, 2009
Houston Texas
The IAC maintains two idle trim values. AC on and AC off. IF the AC is low on Freon this make it short cycle. This will prevent the PCM from re-learning new AC on IAC idle trim values. I suspect what is happening is the idle is too low when the extra load of the AC compressor kicks in. This causes the motor to stall.

The fix? Either fix the AC or jump the AC low pressure switch to force the AC to run long enough (a couple of minutes at normal operating temperature should do) so that the PCM can learn correct AC on IAC trim values.

Troubleshoot IAC idle problems 1996-2004
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