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Bad PCM?

12750 Views 5 Replies 5 Participants Last post by  DavidD
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!
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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 :).
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