Hey folks, I could really use some help.I've got a 1993 Dodge Dakota 5.2 with the 318 Magnum, have had the truck about a year and it's been great. about a month ago I got in it to fire up and it just cranked and wouldn't start, no spark, fuel pressure was good starters good, it was throwing a code 42, Auto shutdown relay circuit fault.. I started digging into it to check relays pulled the box and I found the 3 red, I think, wires going to 1 wire coming from the relay box and the splice was rotten. Put the wires back together and it fired up. Cool. About two weeks ago it stalled while driving, same problem, no spark. No codes this time. Also no check engine light when turning the key over.. so the PCM wasn't communicating. I spent probably 3 hours poking around under it probing wires and the 60 pin, having my girlfriend turn the key back and forth while I checked sensors. Then it just fired up. Hmmmmmm. It stalled while driving again Monday last week. I've got good continuity between the PCM and all ignition associated sensors, crank, pickup/cam sensor, ignition coil, everything is grounded the way it should be, be it the PCM or body ground. The PCM is sending power where it should, when it should. Checked everything with a multimeter. I've pulled every sensor and inspected the wires. I've opened every wire harness engine side and have inspected every wire. Checked continuity between the PCM, sensors, and relay box. All good I bench tested the ignition coil by putting a sparkplug in it, running a hot to the ignition coil wire, green orange I think? And cranking it to check for spark, I had spark so the coil is good. Every ignition related part is under a year old also. It has to be the PCM right.? I just want to discuss and try to verify before I go and pick the up that a guy on facebook is offering.

*Edited to fix typo.

 

I had a similar problem on my '93, 5.2L. For no reason the engine would intermittently cut out while driving or just not start. I could wait 20 minutes and it would fire up again. Went through all the gymnastics you mentioned. Turned out the microprocessor in the ECM was faulty. Could not be refurbished so I just got another ECM that was certified rebuilt. That one did not work at all. Wouldn't even start the truck or crank the engine. They sent me another one. That one worked and still does. That was several years ago. Voltage regulator didn't work in it (common problem) but I bypassed it with an external voltage regulator seeing the rest of the ECM worked perfectly fine. Never had a stall or no-start since. I don't know what your problem is and couldn't tell you what else to check, but yes, I would put your ECM on your suspect list. One train of thought is to get another ECM and try it. If it doesn't solve your problem then at least you have a backup ECM. These OBD1s in these '93s are plug n play...no software validation required. Simply unplug the old one and replug in the replacement. You can get an ECM from a refurbisher, Ebay, or a boneyard, your call. Part number should be on the ECM itself. I believe it ends in 4878 or similar. I can get the actual number if yours is rubbed out.

Wait for other responses as I'm not claiming I am right about your problem.

 

42 Automatic shutdown relay circuit open or shorted
The asd relay supplies power to all critical components so if it doesn't work it won't start. Check the wires/connections from the pcm to the asd relay. Wouldn't hurt to swap out the relay and see if that changes anything.

 

Similar issue with my 95 V6. Awaiting an eBay ECM. On mine the ASD relay circuit coming out of the ECM was the issue. I would have to turn on the key and wait a few minutes. The ASD and fuel pump relay would start humming, then chattering then would lock in and the truck would start once the ECM had "warmed up". Until then, no spark and odd fuel pressure readings from the pump starting and stopping. The ECM pulls them in by pulling the negative relay terminal to ground. Anytime the ignition switch is on, full 12 volts is present at the pump relay and ASD coil. Don't let that fool you. They won't work until the other side of the circuit goes to ground thanks to the ECM.

 

A couple people have mentioned giving it a smack and trying to start it, I haven't tried that but I will today after work. my relays all cycle like they should, I turn the key and the fuel relay clicks and sends fuel then the ASD relay clicks on then off after 2 or so seconds. I'll give the it a good smack later and see what happens, somebody also said to try and heat it up so I'm gonna try that too.
I got a guy offering me one for free from the Facebook Dakota group so when I get a day off, whenever that may be, I'm gonna go pick that up and give it a shot.
Let me know if the new PCM does anything for you because I'm gonna go the same route if I need to and send it to that sia electronics on eBay to have them rebuild it.

 

ECMs with faulty microprocessors cannot be rebuilt. As for "smacking" it. I have tapped on mine with a screwdriver handle when I couldn't get it started and it worked a few times but eventually not even that worked. When the processor goes bad it never heals itself. The frequency of it faulting only increases. You don't have to "smack" it. A few lighter taps on the ECM is all it needs.

 

I really do not think there is anything that can be cost effectively done to fix the PCMs in our vehicles. The circuit board is encapsulated in silicone potting compound that is very time consuming to remove. They cannot be programmed at all. The software is contained in an old school UV erasable PROM chip. Those have to be removed from the circuit board to erase and reprogram (or even just read the chip) and in most other applications are socketed. Our PCMs have them soldered in place, something else time consuming to deal with and carries the possibility of physically damaging the chip getting it out. If you read the disclaimers on most of the rebuilder sites, they warn you that there is the possibility the board cannot be repaired and you will pay a diagnostic fee for them to examine it. Other PCMs don't have that potting and the boards can be repaired more economically. As long as replacement boards can be bought for around $200, there is really no business model trying to do anything with ours besides collecting that fee and telling you it's not repairable. Anyone here actually have their ECM repaired and what did they say they did to it?

 

If you have t buy a computer I just got one off Hollander Parts for $100 delivered. It works fine.
If you want to monkey with yours I remember back around when I first joined this site there was a Canadian poster who said they took their apart and removed the hardened gel the circuit board is encased in (long Canadian Winters I assume ) then went over all of the soldered joints on it with a soldering iron and added some solder where necessary. Claimed it worked fine after.

 

I am in the process of that with mine. I ordered one and want to get it in my possession before I really bear down on cleaning the gook off the board. I resoldered a few spots that looked janky without results. The truck will start and run fine if the ECM is "warmed up". Not going to risk having a totally dead truck if I touch the wrong thing. I'll update once I get the replacement and start getting serious chasing the problem.

 

There are problems finding an ECM. If you get one from a junkyard you don't know what kind of shape it is in or was in. The truck might very well be in the junkyard because the ECM petered out. So it's a risk. You can get a used one off Ebay as well but the same applies to those. Just because you pull an ECM off a junker and list it on Ebay doesn't mean it is in good shape or if it even works at all. As for refurbished ECMs rebuilt by these refurbishers, I am skeptical of those as well. What actually did they do to the ECM? The first refurbished ECM I bought did not work. It didn't even so much as turn the engine over. That tells me they did nothing to refurbish it or so much as test it. All they did was clean it up good and put a security sticker on it. They replaced that one and it worked fine and it still works but the voltage regulator inside of that ECM never worked. Again, do they even test these things? I am highly skeptical.

My view is to have backup ECMs. At least one if not more. I currently do not have a backup but have thought about it for awhile and recently decided I really need to do that and will in the next week or two. Depending on the price, I may get two of them. I'll look at boneyards simply because they can be found much cheaper and buying from a refurbisher seems like a hoax to me. Like I say, I think they get them from junkyards and just clean them up and sell them. Whoop D Doo!