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Old 04-19-2008
Thread Starter
Join Date: Apr 2008
Location: Locust Grove
Posts: 1
ECM/ECU help appreciated!

Good morning all!

My name is Dmitry, I don't actually own a Ranger, but trying to help a great friend in need!

He's wife's company just closed their doors and laid everyone off, and he has 2 kids, to make matter worse, his family car Crown Vic just threw a rod. But wait, there is more, his Ranger started to have electrical issues and non-drivable at the moment with an estimate from some local place for $1500 and no guarantee that it would solve his issues...

So with that in mind, I hope you guys can help me with some ideas so I can try to get his ranger at least back on the road, terrible situation for him, all this crap being dumped on this family all at one time!

Truck - 1998 Ford Ranger 4L 4x4 extended cab (auto and non-california)
Problem - started with not charging battery. Replaced alternator, voltage regulator and battery, still draining and nearly impossible to jump start. Service, check engine and battery light stays on.

He took it to a local shop to get an idea of whats going on with it, and they estimated ECU/ECM, estimate came $1500 with no guarantee that it would solve the problem.

I'd love to help them, but I don't have $1500 laying around. If it is indeed ECM/ECU (main computer module), I know a local yard who will allow me to try few ECM's for a little $$ to see if that solves the problem, I can afford that...

What ECM/ECU's are compatible with this truck (years, models - maybe even Explorer's units) so I know what to look for when I'm at the yard? Special VIN codes or serial number for compatibility?

Any help, suggestions are greatly appreciated on this matter!

Kind regards,
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Old 04-21-2008
Join Date: Nov 2005
Location: Elizabeth City, NC
Posts: 767
First: The charging system has virtually NOTHING to do with the engine computer. There is a connection to the PATS (passive anti-theft system) but as long as the Theft light is not flashing and the starter will crank, it is good. This is NOT AN ENGINE COMPUTER problem.

It sounds like a large draw is killing the battery and the alternator won't charge it. This could be a bad starter, bad battery cable, etc.

Key point here is if you can't jump start it easily, suspect battery cables. New battery should crank it over just fine. If it doesn't, it has to be either a bad connection, cable, or starter (which I doubt). There is also a MaxiFuse under the hood which you should check - 125 Amp - and the 30 amp and 50 amp fuses too.

Locust Grove. Tough spot. I'd be interested to know where this "$1500 estimate" shop is located. Personally, I'd recommend Mullens (on Rt.3 as you leave Fred, on the right side at the Plank Rd intersection) or Little Tire, even closer to town, still on Rt. 3, just past Food Lion after Salem Church Rd. I'd stay away from the schmuck across from L.O.W., I've heard horror stories about that guy (but it was years ago).

But for now, I'd suspect either of the battery cables if it won't crank over with a good battery. That could prevent the alternator from charging too. If you are handy with a multimeter, feel free to call me. I am PM'ing you my cellphone #.
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Old 04-21-2008
n3elz's Avatar
RF Veteran
Join Date: Jun 2004
Location: Kennett Square, PA
Posts: 10,620
Not at all true I'm afraid, Earl. The main problem would be if the battery was high resistance internally. In that condition it does not act like a "capacitor" to smooth and level the alternators output. Under those conditions, alternator output can spike quite high and damage electronics including the engine control module.

Before anything is done, an alternate battery should be tried and if this does no good, you may need to look at the PCM/ECU. Without more test data it's hard to tell. You need a good diagnostician to figure it out and we probably won't from here.
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Old 04-21-2008
Unregistered User
Posts: n/a
do you own a test light or a DVOM?

that would be a good place to start.

also do you know what codes are stored?

i seriously dought you need a PCM.

but if you do

good luck with that though because if the truck has PATS then it will have to go to ford to be re-flashed
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