No communication with pcm. (race truck)

[vanderchevy18]

I'm not getting any communication and I've checked everything I can think of. I'm down to the fact that the instrument cluster is missing. I can't believe that is the problem. It's e99. Ive even swapped pcms. Any ideas?

 

[ToMang07]

I'm not getting any communication and I've checked everything I can think of. I'm down to the fact that the instrument cluster is missing. I can't believe that is the problem. It's e99. Ive even swapped pcms. Any ideas?

GEM/VSM?

 

[vanderchevy18]

I have power to and from it.

 

[vanderchevy18]

Just for giggles I tried to start it. Ignition doesn't do anything but I can jump the solenoid to turn it over. I'm gonna start checking wires from the ignition switch tomorrow. The OD light does come on when I turn the key on though.

 

[vanderchevy18]

OK. The pcm relay under the hood has 12v for the relay power and 12v at the pcm power prong when the key is on. The other two however show .6v. One is supposed to go to the pcm and the other is supposed to be ground. They both show .6v though. I guess I am going to go through and look for a shorted wire.

 

[bigfords]

Try unplugging the ICP, EBP, APP, and MAP each progessively one at a time to see if you get communication to the PCM or the truck starts. Sometimes they will short the BUS (communication) circuit to ground, totally taking out the whole communication network.

 

[vanderchevy18]

Found it. Case wasn't making good contact with ground. Works perfect now.

 

[bigfords]

Which case?

 

[vanderchevy18]

Pcm case.

 

[Jaredkeller96]

Explain? My truck don't start with my ignition key either....


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[vanderchevy18]

It wouldn't do anything. Glow plug relay wouldn't even kick on. The PCM wasn't getting proper ground.

 

[Jaredkeller96]

HMmmmm, my Wts light comes on, but I have a push button start, I'm thinking it's my trans, cause I did a idi to psd swap and the trans are a tad different with the plugs on the pass side


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[vanderchevy18]

Why don't you just run a jumper from the ignition starter wire straight over to the exciter wire on the starter solenoid? Saves you from trying to graft in the stock park/neutral interlock or gear selection sensor if it has Superduty wiring.

 

[Jaredkeller96]

Not sure, my trans is messed up. It recognizes everything but D, like r, 1,2 work great, good response but in D, the ****er barely moves


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[vanderchevy18]

Is it stuck in 3rd or overdrive?

 

[Jaredkeller96]

My od lights on. It barely moves into the garage in D


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[vanderchevy18]

Yeah sounds like an issue you'll have to pull the trans apart to fix.