97 Ranger XLT 3.0 Push-rod, auto, air, 2WD. Just freshened up the heads. Check engine light was on before and after head work. Owner took it to several shops to no avail. No scan-tool will respond to this truck. All fuses are fine, power to the data-port, grounds to data-port also fine, all connector appear to be good. Truck starts and runs although badly especially at higher speeds. Maybe its in 'open-loop'? I've read that the truck won't run if ECU is out. Is this true? What about re-flashing? New ECU? Ford dealer wants $200.00 plus just to plug it in to their scan-tool! Any ideas will be greatly appreciated. Please help as this truck belongs to an elderly gent who can't afford FORD!!!

 

Could be a corrupt ECM I suppose.
Did this scantool link problem come about after some event????

What were the various displayed scantools error messages????

If you Don't suspect something like an acting out alternator voltage regulator, applying an over voltage to the computer & taking it out, if you have a friend with a like vehicle, maybe he would let you try his computer to see if it'll work???? Don't do this if you suspect something is wrong that might damage his computer. So check your alternators under load output voltage before you try a swap.

Some thoughts for consideration, let us know what you find.

 

I'm not sure what event set this off. The history is that several shops have tried to interface with the ECU to no avail. I received it, and diagnosed that the heads were completely gone, and yes the check-engine light was on. After the head repair my scan-tool simply states 'vehicle not responding'. Its a good up-to-date scan-tool. Except of needing a pin-out, everything checks out, power to the data-port and grounds at the data-port are all OK. What I'd like to know for sure is ...some say the truck won't run at all if the ECU is toast. Also it seems that if I install another ECU I may still need to have it programed due to the vehicle anti-theft system, and I'm unsure if this is true or not. Its very hard getting any FACTS on this matter The truck does run, but poorly. I will do as you suggest by checking voltage. Another thought is that stupid alarm system, and how to disarm it altogether. Its got wires going Helter-Skelter from it so I'm not going to fool with it without some sort of wiring diagram, and I can't tell if it something that is stock or not, or if it even has anything to do with the ECU not responding. I could also use a pin-out of the ECU to check for continuity to the OBD data-port, although I doubt that's the problem. Any thoughts AT ALL will be thankful pondered seriously. Sorry for the 'Book' I wrote but...thanx to all for your time....Douglas D. Central Cal

 

Is this an aftermarket, or a factory delivered anti-theft????

 

Possibly something wrong with the connector? Check for corrosion or plugged holes.

 

Yes Paw Paw, it looks to be some sort of after-market alarm. There's a funny looking probe receptacle under the steering wheel on the kick-panel mounted say a foot from the Data-port where you have to push in this funny key that's on the key-ring into it. The truck then beeps twice, you then remove this thing, put the key in the ignition, and is able to start. Now I removed the panel to get a look at this thing, and Brother, there's a black box under there with one hell of a gaggle of wires going every which way. I mean to say a BUNCH of wires, and without any wiring diagram of this thing, I'm afraid to try and remove it.
And yes to the other person I did check all connectors for dirt and or bent pins. I'm rated highly as a mechanic, and have just about every tool I need, and of course like us all, some I don't. I do this as a part-time thing to help out others who can't afford FORD. So I really do value ALL input on this matter in hopes that some of you Ranger guys might know something about this problem. Its got me stumped for now. The trouble is, that this alarm is working and the truck starts and runs with it. I know that there is a sensor out somewhere, but until I get a scan-tool to interface.....wait a minute....if this is on CAN and there's a sensor or sensor connector that's bad would this shut-down communication to the ECU? Or data-port? Hum...Feel free to jump in anyone....

 

Ck grounds on rear of engine . Unplug sensors one at a time to see if you can communicate . If you can there is the problem .

 

Yes JWC 3, I think you're on the right path here, that's what I'm going to do. I read somewhere that CAN is on one circuit or wire. It hard for me to explain, but anyway I'm thinking that if that's the case, and there is some bad plugs where someone didn't unclip the locks before pulling them out, if that circuit is interrupted somewhere...a bad connector/sensor...and it does sound like its running on open-loop...well there it is. Maybe.
Anyways, thank you for taking the time to respond you guys...I really do appreciate all your suggestions, and if you get more thoughts on this matter it will be welcomed greatly.
IF I don't hear back from anyone, then HAPPY NEW YEAR!!!
Douglas D. Central Crazy Calif.