2004 Explorer Failsafe mode after new Alternator

[Will319]

So I have been a fan of explorers for my whole life. I had a 96 XLT with 290k before I rolled it a few months ago. I just bought a 2004 Limited V6 4.0. I knew before I bought it that it needed a new alternator because at high RPMs I recieved a check charging system error. I disconnected the battery and replaced the alternator and when I turned it on I recieved the "Engine Failsafe Mode" Error. It would not rev or go in gear. Tried disconnecting the battery for longer periods with no luck tried again the next day and it started with "Service Engine Soon" message however will drive as normal.

I wanted to know if anyone else has had this problem before and how do I do work on it in the future without it going to the dealer. Also If I have to replace the battery in the future do I have to wait a day to drive it?

I called a ford dealership and they said the PCM has a battery which keeps it alive to hold codes if it loses power. if that battery is dead and the carbattery dies then you need to replace the PCM battery and get it reprogrammed by the dealer for $98.

I wanted to get everyones opinion on if this is a bunch of smoke or if it is something I can do at home or if this is the tip of the iceberg and I should run from these newer explorers.

On another note the alternator solved the "check charging system and the ammeter problems prior to the Failsafe error.

Thanks for your help.

 

[matt0248]

there is a procedure to relearn the throttle. your X has an electronic throttle body. Once you disconnected the battery it lost all calibration. I think there is the procedure in your owners manual, or search this site for idle relearn on 04+ explorers. I think it just involves turning on the key without starting and letting it sit for a few minutes. Not sure 100%.

 

[Will319]

Just an update- I havent been able to find anything on this, however the "Service Engine Soon" light has gone away.

 

[mercuryrising]

just thinking mind you, but if i have the problem i wont disconnect battery, and tape off the end on alternator,while changing it..

 

[Slicer]

For the 04's, if you disconnect the battery longer than a few minutes, the PCM will have to re-learn the calibrations. It's not a big deal, I did it Saturday.
1) Start the engine, and let it idle for 1 minute with no a/c.
2) Next turn on the a/c, let isle for one more minute.
3) Go Drive normally.

That's it, no big deal. The dealership is full of ****.

 

[fatso]

alternater / system

The car computer had to reset it self. any time you put on some thing elec. the computer has to reset it self. my brake system got wet and eng. light came on and it took 3 days to reset. so keep your 04 explorer it`ll be alright.

 

[tcore83]

I had the same problem after replacing the alternator myself. Had my mechanic come take a look, he unplugged the plug with 2 wires that go into the alternator with the engine running and it cleared ip instantly. Plugged them back in and havent had any issues since then.