2001 Dodge Caravan no start, melted 3 pcm's

pggonzo · Posted at Thu Nov 19, 2009 4:53 pm

Engine Performance problem
2001 Dodge Caravan 6 cyl Front Wheel Drive Automatic

this vehicle originally came in as a no start the pcm was burnt, it was replaced and the cause not found, this pcm lasted 2 weeks. the next pcm installed lasted 3 days. again no reason found for the burnt pcm. all wiring to the pcm has been checked, NO opens, or shorts to power or ground, all sensors, injectors, coils,and solonids have been checked,NO problems. All engine compartment wiring has been exposed and inspected and tested, NO problems. Engine cranks but no injector pulse and no coil trigger. pcm has powers and grounds confirmed. 5 and 8 volt outputs - good, cam and crank signals - good, a known good pcm from a running vehicle was installed and still no injector pulse and no coil trigger. on initial crank there is one pulse of the injectors and one spark from the coil, scan tool can command coils and injectors, all scan tool data looks ok. cam and crank are syncronised, tranny was removed to confirm the center did not break out of the flex plate. it has also taken out the cam sensor, crank sensor and map sensor, all have been replaced and are presently working, there signals have been confirmed with a lab scope.
ANY SUGGESTIONS ?

ch112063 · Posted at Thu Nov 19, 2009 8:09 pm

The PCM that it came in was burnt. The one you put in was the same Chrysler number? And this one burned? Do you have the shutdown relay jumped at this time? Is this a 3.3L/ 2.4? Do you now have the old PCM that cooked? Try jumping the shutdown relay, maybe this is grounding internally?
Put the good vehicles in, if you have not already.
The reason I ask is if this has seperate relays or is there just another module with the shutdown and fuel pump relays in it, In 2001 a 2.4 and 3.3L have a module that WAS called a power dist. center, is a intelligent power module. 2 BRN/WHT, 1 brn, 1 org/rd, 1 dkbl/org, and 1 pnk/gry, 1 pnk/wht., these 8 are fuel and engine spark control. Are these seperate relays and a front control module inside too, or one unit? Big change, but looks like one module. jump the brn/wht both to each other, this is shutdown relay. The brown to darkblue/org is fuel relay. Let me know, ok?
See if you have any 12 volt signal to the pink with white tracer wire from key crank position at intelligent power module, left side of engine, this is necessary for both fuel and spark to occur and sustain the engine during operation as the key is brought back to the run position. If you do have 12 volts, then I need to know if it is a 2.4L or #.3L. ok There is a control module in this intelligent power module with another module called a front control module, if this is out, so is spark and fuel pump relays. I will refer to the shutdown relay as a spark relay, ok.
This is seperate from the PCM. So 3(three) modules are involved.

pggonzo · Posted at Fri Nov 20, 2009 3:56 pm

the engine is a 3.3
the pcm installed is the same part number.
does not have skim.
the shutdown relay is not jumped at this time, there is 12 volts at the coil pack and at the injectors while cranking, the asd relay is not shutting down.
yes there is an intelegent power module and front control module, tested and working properly.
power is not being lost, the pcm is not grounding the injector circuits or coil circuits, all other circuits working properly.
fuel pump running pressure 55 psi., cam and crank signals OK, map OK 29.7, cam and crank show sync. cranking rpm OK, pcm powers and grounds confirmed, 5 and 8 volt reference signals from the pcm OK,
all data lines OK, I have communication with all the modules, no codes.
I installed this pcm in another vehicle today and it started and ran fine.

ch112063 · Posted at Fri Nov 20, 2009 6:03 pm

From the start, or NO START rather.
Sorry, but last night, at around 9 or so, I WAS INVOLVED WITH A SIMILAR EVENT AS YOU. let's go back to the beginning. A 2001 3.3l was towed in, no start. The PCM WAS BURNED. dON'T MIND MY CAP'S KEY, IT IS MY POOR ONE-HANDED TYPING ON A KEYBOARD THAT SOMETIMES WORKS, AND SOMETIMES DOES NOT. bUT IT WAS ONLY 9.99. wHEN YOU SAY BURNED, WHERE? Inside PCM Correct? I believe its about the key crank, and run circuit diferrences.
So what would cook a PCM. Since all it does is ground different signals, and also supply 8, and 5 volts to other sensors. It even controls it's own destiny by sort of turning itself on, if a couple of things are correct, do you follow me?
5 volts, shorting to ground would mean some of these sensors would not have voltage, 8volts same thing, as with 12 volts? I'm sure one of them is grounding before their job, intermittantly. If your coil pack has 12 volts in only the crank position, and it does not start,should not have 12 volts after not starting, yet in key run position. The PCM also has field control, right? what if it full fielded it's own alternator, no problem, correct, of course the PCM is protected from that correct? The PCM has no protection from a full field, outside of its own control. Internally of course it will not want to burn up, so there is a safeguard for that, but lets say that it failed. 5 volts, 8 volts to ground also would be bad, a 2000 PCM will never start a 2001. Your having a starting systen problem, you can't test any run condition. Not running.So if this PCM will operate another van, why not start from scratch once again.
In crank position(of ignition) you have starter relay, you have cam,crank, you have fuel. Engines ok also.
you have continuity from coil to PCM. Also from injectors to PCM. than why no coil production(driver), why no injector driver after cranking for a second. Only two reasons, 1. wrong PCM, or 2. No cam,crank signal.fuel, wiring, engine comp. How to tell which? I,ve read your first question. I'll read it again.
I take it you have compression or it would not have alreasdy left, so why did your first PCM fail,The fuel is good correct, all you mentioned are ok? and why isn't the shutdown relay shutting off in the key run position. In the run position. with a no run vehicle. I will ask a couple questions.
At run,key run position, there should be no 12 volts at coil.Only crank position.
un less it is running. And the Cam,crank signal decides that. And Fuel. And Timing, And compression, and PCM. So if your shutdown relay is staying on in the key run position,but its not running, the wire is grounding. Because the PCM is not going to start this 3.3L without it knowing that the cam, crank is working.
I'm sure if your circuitry(wiring) is correct, the problem is that the PCM it originally came in with(towed) was full fielding the alternator, or 8, 5, volts to ground and thus the cooking? and so you put the same part number in and again its cooked? I'm sure this PCM runs a good 3.3L engine, harness, and minivan. And a 2001 also it is working with? Intermittant shorts and opens are the most exciting thing, and frustrating. If this PCM runs another 2001 I'm sure everything you have told me is correct. I feel bad, about your problem. It is so different, a 2001 or 2000.
I Cannot help, if I cannot see, hear, or feel. So please let me know, and if worst comes to worst, we will just jump this new module called a doublestart override(in PCM) ok. Whether the van will be ok as far as charging, well we will see.
I would ask one favor, were any fuses burnt.
I will catch, or hear from you on Monday, ok. Or tomorrow. I now have something in my driveway.
OK sir, you have been so kind to answer me. Thanks. I'm not crazy. Just love electrical shorts, opens, and especially hydraulics. Bye til later.
Can't tell anything with no start, do you still have the vehicle that worked ok with this PCM handy? Thank-you sir.