Computer reset

Joined
Jan 8, 2009
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texas
So It all started when I left the key in the 2015 Fiesta in the on position and drained the battery. I put the battery charger on it and a few hours later, it starts and runs fine. Except the information center says "tire pressure monitoring fault" and the associated dash light flashes.

I took it to a independent repair shop that I've used for a couple decades and they ran three diagnostic systems on it and couldn't find the problem. Said take it to the Ford Dealer. Now it starts to get weird. On the way home in between showing the song/group/radio station, it starts to scroll an advertisement to order a new car from Planet Ford, a local dealer some distance away.

That went away, but today I realized that neither key fob no longer works. I know it did yesterday, because the mechanic used it to toot the horn and find the car in the lot.

Two things I tried were (1) disconnecting the battery. It lost the clock and trip odometer setting, but not the radio station settings. (2) I found a procedure online where you turn the key to run 8 times and push the button to initialize the fob. Followed the rules to the letter, but it never clicked the door locks like it should to indicate its ready for programming.

Any words of advice? I hate to take to the dealer.
 
Joined
May 7, 2004
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Nokesville, VA
Disconnect the battery for 5-10 minutes to reset everything. If you only disconnected the battery momentarily, that may not have been long enough.

The low battery voltage when the battery was drained may have put some modules into a confused state.
 
Joined
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Caldwell Idaho
After doing the above clean the battery cables and battery terminals . Check the chassis ground .My daughter has a 2010 Fiesta and though it is different it has similar problems with low battery, dirty terminals and a poor chassis ground.
 

BlueOvalFitter

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Disconnect the battery for 5-10 minutes to reset everything. If you only disconnected the battery momentarily, that may not have been long enough.

The low battery voltage when the battery was drained may have put some modules into a confused state.
I was told a few times to turn on the headlight switch after disconnecting the negative battery cable. I have done this each time not knowing if it helps. Anyone? 🤷‍♂️
 
Joined
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I was told a few times to turn on the headlight switch after disconnecting the negative battery cable. I have done this each time not knowing if it helps. Anyone? 🤷‍♂️

Theoretically that would discharge any capacitors in the modules that might retain a charge, but pushing the brake pedal to turn on the brake lights might work better on some cars, since that's more likely to be a direct connection to the brake lights with no modules or relays.
 
Joined
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MO, USA
Disconnect the battery for 5-10 minutes to reset everything. If you only disconnected the battery momentarily, that may not have been long enough.

The low battery voltage when the battery was drained may have put some modules into a confused state.
WITH terminals off the battery connect together to drain any capacitors, press brake pedal, now reconnect and lookup procedure for resetting monitors and follow it exactly, my Buick was very particular, if you did not do excactly what it said, no joy !!
 

Burt

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Jan 8, 2009
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texas
Did you take the cables off to charge it? How old is your battery charger?
No I didn’t. My battery charger is old, but I did use the automatic setting.

Does this mean I shouldn’t jump a car as well?
 
Joined
Jan 24, 2013
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Upstate NY
No I didn’t. My battery charger is old, but I did use the automatic setting.

Does this mean I shouldn’t jump a car as well?
Hah! I ask because there are some old chargers in garages (including mine) that are pretty sloppy with their voltage and amperage outputs. You used an auto charger so you're fine.
I found a battery charger in my garage from the early 60's I think, and I was bored so I tested the output voltage, it was very erratic. It buzzed loud and the volume would spike and it would jump to 19v.. Most of the time it varied between 7v - 9v. I I used it in my shooting alley for something to hit.
 
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Odd title made me think of this, have read thousands of stories about it over the years


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Joined
May 4, 2017
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396
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VA
Get a second opinion on the BCM module. Also, for an electrical reset remoce the cable from the battery (negative first) and short the cable together for at least 10 minutes.
 
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