Here's hoping someone can help. Any ideas are welcome.

On my way to pick up my son from school on a very cold day, the power steering reservoir plugged up, overflowed and the vehicle shut down. The reservoir has been replaced yet it won't crank. The morning after tinkering with it, it started up and I took it around town with no issues whatsoever, parked it and, once again, it won't crank.

All fuses and relays are good
the starter is good
the fuel pump is good
the camshaft position sensor was disconnected and didn't open up comm.
I have not been able to get to the crankshaft position sensor yet
I have replaced and added ground straps to no avail.
The key dance does not function nor does the code reader due to the lack of comm but the instrument cluster returns a
100.0 LOOP-BACK FAILURE
100.6 SBEC/DEC/MCM COMMUNICATION FAULT
400.1 IMPROPER POWER DOWN DETECTED

PCM Pin voltages are as follows:

Pin 20 FUSED IGNITION SWITCH OUTPUT 12v
Pin 32 CRANKSHAFT POSITION SENSOR 5v
Pin 41 SPEED CONTROL SWITCH SIGNAL 5v
Pin 42 A/C PRESSURE SENSOR SIGNAL 5v
Pin 43 SENSOR GROUND 5v
Pin 46 FUSED B(+) 12v
Pin 61 5 VOLT SUPPLY 5v
Pin 64 A/C COMPRESSOR CLUTCH RELAY 12v
Pin 67 AUTOMATIC SHUT DOWN RELAY 12v
Pin 72 LEAK DETECTION PUMP SWITCH 12v
Pin 73 RADIATOR FAN RELAY CONTROL 12v
Pin 74 FUEL PUMP RELAY CONTROL 12v
Pin 77 LEAK DETECTION PUMP SOLENOID 12v

I'm not one to subscribe to a PCM failure. I'm not sure what I did to get it to run again as I was all over place. So if anyone can see a clue from the data provided please, please, let me know.

Thanks.

 

Here's one possibility that sort of fits everything you've described - it might be completely off-base, but I'll throw it out anyway.
One really common problem in our early 4 gens is the infamous melted wiring harness, specifically the section of injector wiring harness which runs directly under the P/S reservoir. That said, now come all the ifs.
If your harness was already partially melted, the fluid running out of the reservoir and down into that wiring could easily short out the wires and kill the engine. Next, if you "fiddled" the right way, it might have moved those wires enough to temporarily eliminate the fluid shorting effect, allowing it to start and run. Next, if there was still more fluid down there, it could re-short. Now comes the bad if. If all of this did happen, one common by-product of this melted injector harness is the PCM getting fried. The one piece of this not fitting too well is the no crank, but I guess if the PCM is getting garbled up by the shorting wires, perhaps it's possible.
You can check for the melted harness by lifting the P/S reservoir, removing the outer covering on that part of the harness, and carefully examining each wire individually for melted insulation.
Hopefully it's none of the above, and turns out to be something much less costly.

 

Thank-you, I'll check it.

 

Does the starter relay click when you turn the key to start? Do you need PCI data bus wire diagrams? I'll need an email address via a private message.

 

Only the accessory relay clicks. When I do the key dance, instead of displaying codes, I hear 3 or 4 clicks from coming from the area under the dash near the switch for the lights.

I have another problem, I disconnected the tps sensor and now it's lighting up all the gears *sigh*.

(Update: the TPS sensor is working properly)

 

Get someone to hold the key over while you take a small hammer and tap the shell of the PCM.






The MAP sensor wires run in that loom. It could definitely shut the BUS down if it's shorted to ground.

 

I have unwrapped the wires from under the power steering but still haven't found any visible problems.

 

Does anyone know if the PCM from an 02 caravan with a 3.3L would be compatible with what I have (2003 grand caravan sport 3.8L)?

 

I did give the PCM a few love taps, no change.

Still stuck with this no crank.

Any ideas? Please.

 

Did some additional tests at the IPM

The starter relay is hot at pin 30 and becomes hot on pin 86 during cranking (still no crank)

The fuel pump relay is hot on pin 85 and 87

I did a parasitic load test which was inconclusive.

Ideas?

(more info on next page =>)