1999 Explorer PATS Problem

[jscondra]

My PATS system goes into alarm only when the Ambient Temperature is in the upper 80's or Low 90's and it will not start. I have had it to the Ford garage 3 times and they have been able to get it to do it while at the garage. I have had new keys made and the system reprogrammed. The last time it happened I had to leave it at work and when I came back the next morning when it was cool out, it started right up. If anyone has any ideas, I would be glad to hear them.

 

[2000StreetRod]

condensation?

I wonder if it might be a condensation problem. Does it happen when you leave the A/C off?

 

[jscondra]

I wonder if it might be a condensation problem. Does it happen when you leave the A/C off?

I don't think it would be that because my vehicle sat out in the sun for 10 hours, I got off work, got in and put my key in the ignition and it immediately went into alarm and would not start.

 

[2000StreetRod]

battery voltage?

It could be a low voltage supply problem. The PCM acts weird when supply voltage is low. I suggest measuring the battery voltage from post to post and compare that to the voltage from the positive battery terminal to chassis ground. You may have corroded posts or terminals. The terminals may not be tight. The ground cable to chassis terminal may be loose or corroded.