[Rhodo]

My 97 died the other night. No rpm's while cranking, no wait to start light. Check engine light on. Fuse 22 was NOT blown, nor were any others (except the trailer battery charge fuse #18, explained by a recent trailer wiring job) All the fuses have power to them and thru them and all were checked with a meter. I tested the 6 relays at the UH fuse location. I put in my spare CPS. The batteries are very old, but it cranks strongly and my smart charger indicates no problems with them. There were no intermittent problems leading up to this. After reading lots of threads, it seems the combination of no tach and no WTS light and no blown fuses point towards the PCM. I do not have a scan tool, but may have to buy one.
Have I missed anything? Are there any other relays I need to test? What does a PCM cost and who has the connection that can save me $$. Speaking of connections, are there any I need to check, other than at the PCM itself. Do PCM's just abrubptly fail like that or is it likely something shorted it out, even without blowing a fuse? I'll try anything you all can throw at me. Thank you!

 

[Patrick Feeley]

Depending on what happened (if anything) to the pCM, it may not communicate with a scan tool (and if you get one make sure it works on the Ford Diesels!). I had the PCM go bad on my 94 and the only thing it wouldn't do was power up the IPR (it would communicate with my scan tool, run KOEO tests, etc.). Do you have a chip installed? If so, remove it and see if that solves it. I don't have the PCM connector pinout handy, but if you can find it, you may want to check for power out to the PCM connector pins. Assuming your truck is not a California truck with splitshot injectors (PCMs are hard to get for these), you could try someplace like RockAuto for a PCM (I picked one up from them for $115 plus refundable core). Cheers!

 

[Rhodo]

yeah, I know a bad PCM might not communicate with a scan tool. But that would tell me a lot. I should have a scan tool anyway, since this truck is now 14 years old. $115 aint bad for the PCM. I know there are at least 2 outputs from the PCM that aren't functioning, the tach and the WTS light. Nobody chimed in on the scan tool, but the one I see recommended here most sells for $350. I've come down with a cold, so I'll get right on it when I feel better. I'm surprised more people didn't respond, prolly all drunk from the 3 day weekend .

 

[ryhed]

we were never sober. You can always return the pcm, or re sell it.

 

[Mark E.]

Tesla, I had a similiar problem I haven't posted back on yet. I know I had no rpms on tach, had the WTS light, and IIRC no CEL. Pointed straight to the CPS, which in fact was the circuit affected. I HAD a chip in it. After everything else failed I removed the chip & it started. I still had to replace the computer because the CPS circuit became intermittent. Looking at the chip I'm convinced one of the contacts became weak causing the problem, even though it was very secure prior to removing. The computer I bought from O'Reilly's claimed it needed to be "programed" by the dealer. The shop I found (not Ford) told me they updated calibration, but as I understand it they pulled my program TDE0 and installed it on the new one. Still plan to check that for sure.

 

[DavidD]

The 1 I bought stated something about needing to flashed to reconfigure the anti theft to the vehicle.