how can I tell if the computer (PCM) is bad
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Senior Member
Joined: Jun 2008
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From: Texas
how can I tell if the computer (PCM) is bad
what the title says
my truck has no spark and the rpms do not register when cranking the truck so I replaced the Crank sensor and still the same thing, I know fuel is going to the cylinders but the thing is just not sparking and it I am almost positive it is not the coil packs because they could not have gone out overnight(literally)
but anyways since I am almost sure it is the computer (unless there is a relay) how can I tell if it is really that without buying a new one
my truck has no spark and the rpms do not register when cranking the truck so I replaced the Crank sensor and still the same thing, I know fuel is going to the cylinders but the thing is just not sparking and it I am almost positive it is not the coil packs because they could not have gone out overnight(literally)
but anyways since I am almost sure it is the computer (unless there is a relay) how can I tell if it is really that without buying a new one
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Joined: Oct 2002
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From: St. Louis (Out in the woods)
Does the CEL come on at ignition power on? If not, the PCM probably isn't getting power.
Check fuses F24 & F30 in the under-hood box and the PCM Power relay.
If either fuse is blown, there are common reasons.
Check fuses F24 & F30 in the under-hood box and the PCM Power relay.
If either fuse is blown, there are common reasons.
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Joined: Dec 2003
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From: Mount Airy,MD
Some years ago, I had a similar problem. Fuses and everything was okay, but there was a fuseable link that went out making the PCM not get any power. It would crank all day, just never start.
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From: Mount Airy,MD
Sorry, don't know. As the vehicle was under warranty, I just let the dealer deal with it. Just got the explanation.
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From: Calgary, Canada
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From: Central NJ
Check the fuses and relays under the hood of the truck. The pcm relay is one of the three larger ones ( the others are the fuel pump and horn) and you can swap them around to check them.
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From: Texas
Well I started to check all of the fuses and I started inside and a 30 amp fuse (numbered 30 on the little chart thing in the fuse panel) was blown so I replaced it and I am charging my battery and hopping that that will have been the problem
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From: Texas
SUCCESS!!!!
turns out it was that fuse...man that sucks that my truck was brought down by something smaller than a nickle
however my truck still does not start up immediately when I turn the key what happens is the starter relay clicks but the starter does not turn I may need to pull my starter and clean it(it looks to have a lot of oil on it) and hopefully that will solve my problem
turns out it was that fuse...man that sucks that my truck was brought down by something smaller than a nickle
however my truck still does not start up immediately when I turn the key what happens is the starter relay clicks but the starter does not turn I may need to pull my starter and clean it(it looks to have a lot of oil on it) and hopefully that will solve my problem