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I have a 2002 dakota 4x4 4.7l manual transmission. the other day it left me dead at mcdonalds when the guy in the window said "Have a great day." after pushing my truck from the window with help from the two dodge owners behind me, i am on my way to ? not sure, but hoping to confirm before tossing money into this recently purchased high milage truck.
Ok, cluster test gave 920,921,999 codes. all fuses are good and i have tossed in a new crank shaft sensor. renting an obd2 reader for a deposit of 140 bucks at auto zone has left with waiting 3 to 5 business days waiting for my deposit to come back and nothing else. I am seeking away to confirm that the pcm is toasted before dropping the money on one as i am done 140 bucks thanks to auto zone. Anyone have suggestions or the path i need to get my answer?
 

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ScanMan, here are some checks you can make.
This is not from the FSM but from Haynes.

To paraphrase:
"test for battery voltage to the coil by disconnecting the connector from the coil & using a MM to check for volts at the dark green/orange wire with the ignition ON.

No voltage=bad ASD relay.
If volts: use the ohm-meter function of your MM & check primary & 2condary resistance of the coil. My Haynes lists 0.95 to 1.20 ohms & 11,300 to 13,300 ohms respectively, but I believe Haynes is giving me inaccurate specs on that.

If coil ohms out good: check the trigger signal from the PCM
. Using an LED test light (inexpensive from Advance or the like) back probe the coil driver terminal (black/gray wire) & check for a flashing light as an assistant cranks the engine.

If no flash: then check the operation of the cam position sensor & the crank position sensor.

If those sensors test good: send the PCM out to be diagnosed."
 

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Thanks, I'll give this a try and see what I discover.
Good luck with this.
The Haynes I quoted from lists its applicability as '00 to '04 so the wire colors it describes SHOULD be the same.
My Dakota is an '03 & I did determine my PCM to be at fault using this procedure.
 

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Good luck with this.
The Haynes I quoted from lists its applicability as '00 to '04 so the wire colors it describes SHOULD be the same.
My Dakota is an '03 & I did determine my PCM to be at fault using this procedure.
Well, I got mixed results. I no volts at coil, swapped relays with known good relay, no change. Ohms out within specs. I'm wondering if I should start a new thread? There are already so many on here with a crank no start and no bus issue but mine seems to be playing by different rules. i don't want to hijack a dead thread from a year ago.

I have good grounds, I have the 5v reference at all sensors, tried unplugging each sensor, no change. Checked and rechecked fuses both in and out multiple times now. Scan tool will connect no errors but loses connection when I try to view live data of the crank sensor while actively cranking the engine (may be normal?). This one is really getting me stumped. I'm wondering if the ignition switch could cause this?
 

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Is this an '02 4.7, same as the OP's is?

A couple of things, but I'll start with a possible amendment to what I typed previously.
In my hand written notes on checking for volts to the coil, I have written that the green/orange wire to the coil will have volts on it when initially turned on & then while cranking. Now that is not exactly what my Haynes says, so I am not sure what drove me to to write that note (it was a few years ago) & that note may actually have been in error. But maybe it's worth trying again to see if you actually do get volts there when you crank.

ON EDIT: Looking at the schematic, all I can say is that my handwritten note must have been an error. The way that is laid out, cranking or not cranking should have no effect on reading volts at the green/orange wire at the coil.

As far as the "NO BUS" message, I may be wrong, but it is my understanding that that message means that the PCM is not communicating with one or more sensors.

Going back to checking for volts at the green/orange wire & not getting voltage (which, according to Haynes means bad ASD relay) & swapping out relays with no results, I'd think that this at least indicates that your issue is before the PCM. (At least one of your issues is.) Unfortunate I am looking at a Haynes with generic prints from 00 to 04, but basically it is showing the ASD relay connected (by a GY wire)on one end to a 30 amp fuse which is "hot at all times" & on the other end the green/orange wire goes to the coil where it is supposed to provide battery voltage with only one connection (I guess it is a terminal & it doesn't say where it is) in between. I am a parts changer, at best, & troubleshooting (particularly electrical) is hardly a forte of mine, but I would think that if you are not getting volts at the wire from the ASD relay & you have a known good ASD relay installed, it would indicate something in front of the ASD relay, & it APPEARS to me that the first thing would be that 30 A fuse (or I guess that one terminal or connection between the fuse & the coil?). Maybe take your multi meter & check for volts on both sides of that fuse as your next step. I hesitate to give advice like this: but theoretically, shouldn't a jumper straight from a 12v source to that post on your coil give you a start condition if your only issue is 0 volts to coil?

And as far as starting a new thread on this, it might be a good idea & perhaps someone who is better with this stuff will jump in.

Well, I got mixed results. I no volts at coil, swapped relays with known good relay, no change. Ohms out within specs. I'm wondering if I should start a new thread? There are already so many on here with a crank no start and no bus issue but mine seems to be playing by different rules. i don't want to hijack a dead thread from a year ago.

I have good grounds, I have the 5v reference at all sensors, tried unplugging each sensor, no change. Checked and rechecked fuses both in and out multiple times now. Scan tool will connect no errors but loses connection when I try to view live data of the crank sensor while actively cranking the engine (may be normal?). This one is really getting me stumped. I'm wondering if the ignition switch could cause this?
 

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. . . I just edited my last post to this,
but,
let me also throw this at you.

From another handwritten note (I am not absolutely 100% positive, but I think I took this from a post that Old Marine made, & he was quoting the FSM)
I wrote that: "if the PCM senses no signal from the crank or camshaft position sensor(s) it will deenergize the ASD and the fuel pump relay."

Meaning to me: that if either your crank or cam sensors were bad, you would not read voltage at the green/orange wire at the coil.
 

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. . . I just edited my last post to this,
but,
let me also throw this at you.

From another handwritten note (I am not absolutely 100% positive, but I think I took this from a post that Old Marine made, & he was quoting the FSM)
I wrote that: "if the PMC senses no signal from the crank or camshaft position sensor(s) it will deenergize the ASD and the fuel pump relay."

Meaning to me: that if either your crank or cam sensors were bad, you would not read voltage at the green/orange wire at the coil.
Thank you for the information. Yes, the truck is the same. 2002 4.7 RWD, with the exception of mine is an automatic. I will do some more in depth testing on this circuit before moving on to something else. I have a pdf of the FSM but trying to follow there wiring diagrams has a bit challenging. I have a Chilton manual as well for this truck, but my old man security system got activated the last time I used it and I put it "somewhere I'll know where it's at" and have yet to relocate that great place again! If I come up empty handed on further diagnosing, then I'll start a new thread with all the current details of where I've been so far. Thanks again for your input.
 

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I think you need to figure out why you are not getting 12v at the coil from the ASD relay.
Good luck on this & let us know what you come up with.
 

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Check this out!
(This is a quote from Old Marine related to the ASD relay to a thread by someone who couldn't get a trigger signal from the PCM to the coil. Old Marine usually gets his stuff straight from his FSM.)

"The coil and the fuel injectors are powered by the ASD (automatic shutdown) relay. The ASD relay is controlled by the PCM and will cut power if (1) the ignition key is left in the Run (not Crank) position without the engine running for approximately 2 seconds, or (2) the PCM does not receive a valid signal from the crankshaft position sensor (CKS). So you could check that the ASD relay is operating properly and you could check that the CKS is good and the wiring to the CKS is good."

Okay, this would explain my first handwritten note about getting 12V at the green/orage wire to coil when initially turning the key 'ON' & then not getting it again until I cranked it over. So all I am getting at here is it might be worth double checking & making sure that you are truly not getting 12v there. If you had the key 'ON' & then had to screw around a bit before you got the probe of your MM on the wire, the PCM would have already de-engerized the ASD relay.
 

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Okay, thanks for the additional info. This does seem to be more in line to what's going on. I will let you know what I find. It'll be a few days (likely weekend) before I'll have a chance to have another go at it again.
 

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Well after a lot more testing and tracing down wires, I think I have narrowed it down to being the PCM. Everything else checks out so unless I'm still missing something somewhere that's the only thing left that I can't definitively test with the tools I have available. I've had the feeling it was it all along but just don't understand how it can work fine one day, be parked for a few days and then be dead when I go to start it again. I guess I'm just glad it didn't dump me along the road somewhere.
 

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That's the way mine was, except I was lucky in that when it decided to shoot craps & then crank but not start it was always in my driveway. I find intermittent stuff hard to troubleshoot but when it devolved to terminal with volts at the coil but no trigger signal to the coil I moved towards PCM. The place I sent it to diagnosed a loose pin that they resoldered (which, I suspect is what made it initially intermittent), and, although my memory has faded a bit, they said they replaced a part, I think they said it was the coil transistor. And if so, that may have been because I described the the findings I got when back probing my coil wires.

Here is a thread that started as a result of someone having similar issues.

 

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Thanks. Looks like there are a couple websites people have had good luck with. If I can't get it done locally I'll likely send it to one of them. Thanks again for all your help.
 

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I wish you well on this, ScanMan. It sucks to be driving a vehicle that you don't trust.
I just reread this entire thread & I had mistakenly forgotten that you were not the OP; among his symptoms were 3 codes related to his transmission (weird, huh?) (on edit: especially since those appear to be codes for an AT & he says he has a manual!) &, unlike you & I, he was also the one who did break down on the side of the road.

Anyway, relooking at the notes that I had provided related to the crankshaft position indicator & your first post on your scan findings on the crank pos indicator, did you, in fact, find a way to definitively eliminate that as a possible suspect? (When I was working on mine in the intermittent mode, I felt that I had eliminated it by ordering one from Rockauto & replacing it.) Just curious, is all.
 

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Thanks. Yeah... the crank sensor... Man, what I nightmare that turned into. I was trying to ohm it out and check functionality and being in such a tight spot I couldn't for the life of me get a good reading. So I attempted to remove it to bench test it and it was so corroded in the hole that between trying to wiggle it out and my keen gorilla prowess, the old plastic gave up the ghost on me and I broke it off in the engine. Several hours of work and days later I was able to drill it and finally get the other part out. Put in a new crank sensor and did the cam sensor while I was at it for good measure and, nothing. Didn't change a thing. All the headache created was in vain.

After reading your post about possible timeout on the voltage for the coils, I got it setup with the meter on the windshield so I could see it as I turned the key and sure enough, there it was, battery voltage. So my first results were flawed because I had already had the key on and then was probing around looking for voltage that had apparently already been turned back off.

So with all the following checking out; all sensors, 5 volt reference good at all sensors, grounds all good, getting good results testing the connector pins at the PCM being good (unable to check PCM coms), fuses, and wiring just leaves the PCM if I'm not mistaking.

This is the first issue in a long time that I've really struggled with getting the issue diagnosed and repaired. I'm hoping that I can find somewhere local that can at least test the PCM to confirm before I shell out the money for a replacement one. Knowing my luck, I'll buy a replacement PCM and it still wont work only to find out that I only needed to replace the burnt out license plate light. (kidding of course). :)
 

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Wow and yuk!
Not all in vain -- look at the positive side, now you KNOW you have a fresh crank & camshaft position sensor installed.
Yeah, if I was in your position I would be thinking PCM.
I am not putting a plug in for the place that did my PCM (SIA Electronics), but they advertise (at least they used to) that they will bench-check your PCM & if it tests good on their bench that they will send it back to you for only the bench-check fee plus shipping.

Just something to keep in mind is all, as all that I know about these guys is my one previous experience with them.
 
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