2001 mustang gt

I have a 2001 mustang gt and it will crank but won't start!! The theft light blinks rapidly with key in the on position and while I'm cranking it !! Also there are dashes on the odometer meaning I'm getting no communication from the pcm !! Any recommendations?

With the key light flashing it sounds like a key fob issue. You can connect a scanner and see what codes are present. Go into the immobilizer menu and it should tell you if your key is being read. Also, Try a different key. You will need 2 good keys to reprogram.

I was thinking that the odometer screams communication issue, and the anti-theft light is a reflection of that.

Since you can't talk to the PCM, I'd start with powers and grounds at the PCM itself. Before you go there, you can start with B+ at pin 16 of the DLC, and ground at pins 4 and 5.

Load the grounds with a bulb or the like. No ohm meter. I recall Ford using stupid little single pin ground connectors near the battery, and they like to corrode or unplug themselves due to lack of tension.

I tried checking a few pins on the pcm harness with a test light and got nothing

I tried both of my keys and neither of them work

Rickyb1982 wrote: I tried checking a few pins on the pcm harness with a test light and got nothing

I would be very careful poking around your computer with a test light.

Do you have power & both grounds at the DLC? pinoutguide.com/CarElectronics/car_obd2_pinout.shtml

If the DLC is OK, here are some wiring diagrams to help check at the computer:

www.revbase.com/BBBMotor/Wd/DownloadPdf?id=28635

www.revbase.com/BBBMotor/Wd/DownloadPdf?id=28636

Check all powers & grounds & get back to us. Don't use a test light.

What is the best way to check the grounds ? I've never messed with any of this before

Rickyb1982 wrote: What is the best way to check the grounds ? I've never messed with any of this before

Did you check the DLC, powers & grounds? Check that first. Trying to see if your no communication issue is caused by a fuse or something. Pin 16 should be battery positive. Pins 4 & 5 should be ground. If power & grounds are OK at the DLC, then move on to the computer.

I'm worried that you could fry the computer by testing with the test light. Check the power leads with a DVOM. OK to check grounds with the test light. Unplug the computer & hook the test light up to battery positive. Light should light when the test light touches a ground connection.

Record your readings & let us know. If powers & grounds are OK, we will have to check outputs from the computer.