Car will not crank

Tiny
ROY9319
  • MEMBER
  • 2002 MERCURY SABLE
  • 3.0L
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 93,000 MILES
Theft light flashes rapidly. Checked rx an tx wires from pats harness to PCM, continuity okay, and has voltage. Installed new transceiver module and had a locksmith reprogram keys. Still no crank. Then had dealer flash the PCM and it still will not crank. I should mention that after removing PCM harness and checking the wiring, the car started one time! Then no crank again. It looks like the key code is not being written to PCM memory. Cannot think of anything more I can do. Any advice would be appreciated. This Ford PATS system is ridiculous!
Monday, July 31st, 2017 AT 11:36 AM

5 Replies

Tiny
STEVE W.
  • MECHANIC
  • 15,233 POSTS
If removing the harness allowed it to start once I would check the connector and harness real close for a bad pin or damaged wire. It could simply be a loose pin.
Do not overlook the dash either. Ford loves to run all the signals through the instrument panel, a bad connection there could also cause this problem.
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Monday, July 31st, 2017 AT 12:49 PM
Tiny
ROY9319
  • MEMBER
  • 3 POSTS
Great idea Steve. I agree this could be the problem. I will give it a close look and get back with you.
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Monday, July 31st, 2017 AT 1:19 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Please let us know what you find.

Cheers, Ken
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Wednesday, August 2nd, 2017 AT 1:44 PM
Tiny
ROY9319
  • MEMBER
  • 3 POSTS
Checked all wires and pins. All ok. Found a Ford guy with the fancy Ford scanner. He did a PCM diagnostic and evidently the area where VIB writes to memory is malfunctioning. So, I suppose I will either have to get the PCM rebuilt or find a replacement that still works and get it reprogrammed to my VIN. What say you?
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Wednesday, August 2nd, 2017 AT 4:30 PM
Tiny
STEVE W.
  • MECHANIC
  • 15,233 POSTS
Shouldn't be difficult to find one that is OK and get it flashed. Not the first time an ECM refused to write properly.
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Wednesday, August 2nd, 2017 AT 11:39 PM

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