I need one or both of your guy's help....at another site in the 4.9L section there's a debate about how to reset the OBD-II PCM on the older body F150(96), someone is saying the only way to reset it is by using a scanner to reset it, but I think I was told by PKRWUD to just disconnect the neg(-) battery cable and turn the headlights on for atleast 10 minutes....even the guy's at AutoZone and the dealership have told me this, and this is what I see all the 97-03' guy's doing also. I've alway's reset it that way on my truck and it's worked every time.

 

Disconnecting the battery removes the power supply. Turning on the headlights drains any capacitors left alive in the system. That destroys the volatile (i.e. learned) portion of the memory. The PCM will then be back at whatever base (i.e. permanent) settings were in place. To alter the base settings requires re-flashing the EEPROM in the PCM which requires a computer, specific software and to do it right access to a chassis dyno. The scan tool can probably be used to alter settings in the volatile memory but Ford isn't studip enough to let every Billy Bob with a scanner have access to the EEPROM

 

ok now I'm going to link this to prove I'm right.....thank you.

 

To completely reset the ECM:

1) Disconnect the negative battery cable
2) Turn the headlight switch on
3) Wait 10 minutes
4) Turn the switch off
5) Reconnect the battery cable

That resets it, and drains the capacitors (as mentioned).

After resetting the ECM, you need to relearn the ECM:

1) Start the engine, and allow it to idle for 1 minute.
2) Shut it off, and wait 10 seconds.
3) Start the engine, and turn on the headlights on high, and your a/c, with the fan on high, and let it idle for 1 minute.
4) Turn all the accessories off, and turn the engine off, and wait 10 seconds.
5) Start the engine, and make it idle @ 2000 rpm for 1 minute.
6) Shut it off, and wait 10 seconds.
7) Start the engine, and turn on the headlights on high, and your a/c, with the fan on high, and make it idle @ 2000 rpm for 1 minute.
8) Turn all the accessories off, and turn the engine off, and wait 10 seconds.

This is the best way to relearn the ECM, but you should take a 10 minute test drive afterwards to make sure all is well.

 

Good information, I'm printing that one out.

 

Or just pull out the EFI fuse for a few minutes. Clears the ECU without losing your radio stations. This doesn't work on the new trucks because they can keep there memory for up to 5 years without a power source, but it should work on all pre 97's.

-Jon

 

StrangeRanger:
I think I've seen you at ford-trucks.com, if you're a member there could you do me a favor and clear this mess up?
http://www.ford-trucks.com/dcforum/D...9/2160.html#18

If you don't want to get involved it's cool, it's just realy annoying me.

 

Resetting the eror codes is different from resetting the volatile memory. To reset the memory, you need to do the battery/headlamp thing. Error codes would likely be handled differently, but The power supply for them is not infinite, there has to be some way of draining it to reset.

 

I forgot I was registered there. I went and explained myself. It was my 4th post! I'm such a post *****!



Take care,
~Chris

 

Thanks....got my 2 hit men backing me up

I was just saying what works for me and my neighbor to clear the codes and WAM! I start a big blabber fest.

That's the last time I wonder out of this board...except for FTW.

 

you need to check out www.fordsix.com if you haven't already done so. Lots of 240/300 enthusiasts there.

 

I usualy check that site a few time's a day....I only have 1 post but I usualy just read other's.

I'm a blabber mouth here and at FordTruckWorld.com

Gawd I love my job.....I rat out to the boss when people are abusing the network, except for my self LOL