# The Great POS Grand Caravan No Crank Mystery



## Nut'n'Done (Nov 28, 2021)

How many miles are on the van.
Have you serviced it regularly?
Regular oil changes etc.
Is the engine light on? 
Do you have a code reader ?


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## sidewayz (May 9, 2010)

Nut'n'Done said:


> How many miles are on the van.
> Have you serviced it regularly?
> Regular oil changes etc.
> Is the engine light on?
> Do you have a code reader ?


I have no idea how many miles are on it as the odometer readout is DOA. Its my friend's vehicle... by the looks of things, it hasnt been kept up with servicing, including regular oil changes. The engine is not seized as i just performed a manual relay jump to trigger the starter from the TIPM. It rotates freely. No, there isn't a check engine light. I have an ODB2 reader but it cannot establish a link with the vehicle. Im beginning to think Im looking at a faulty PCM?


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## sidewayz (May 9, 2010)

Regarding the Data Link, I verified the port is getting power and has a good ground on both pins 4 & 5. I also verified a 5V reference from the PCM. Still no com tho🤷‍♂️


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## HotRodx10 (Aug 24, 2017)

Have you tried bypassing all the controls and supplying 12V directly to the solenoid? In the 'old days' we'd just stick a screwdriver between the bolt for the solenoid wire and the main starter cable lug, but if you don't like sparks, it might be better to find a connection in the solenoid wire to unplug and connect a jumper wire from the solenoid wire to the battery.

I just reread post#3 - so it seems the problem is either before the relay or the relay itself. I'm not sure what you mean by "manual relay jump" - supplying power to the primary side to trigger the relay, or jumping the secondary side to effectively bypass the relay. If you bypassed it, I suggest you try powering the primary side to see if the relay works.

If it's not the relay, it could be the ignition switch.

It could also be locked out by the ECM, which doesn't necessarily mean the ECM is faulty. The ECM may be functioning correctly, but receiving faulty input, such as an out of position switch that doesn't register that the shifter is in park (or neutral on some vehicles). There may be other protective lockouts, as well.

Also, have you manually checked for continuity on all the possibly involved fuses? Sometimes you can't tell visually that they're burned out.


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## lenaitch (Feb 10, 2014)

Given post #3, I think POS may be a little harsh. It sounds like it's been neglected and now it's returning the favours. With the erratic powering of accessories, it might not be ECM and I don't know if they had a BCM back then. There are so many sensors that it could well be a faulty ECM. I don't know about compatibility but did 2005 use OBD2?


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## raylo32 (Nov 25, 2006)

Does this have a chip key or other starter lockout security system, to include aftermarket? Is a "security" light illuminated on the dash? Have you tried the other key?


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## HotRodx10 (Aug 24, 2017)

raylo32 said:


> Does this have a chip key or other starter lockout security system, to include aftermarket? Is a "security" light illuminated on the dash? Have you tried the other key?


If it's like mine with a chipped key, without reading the code from a valid key, it will still crank, but it won't start.


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## raylo32 (Nov 25, 2006)

Interesting. What brand? On GMs I have worked on they won't even crank. Not sure about my Tacoma since I have never had that sort of issue.



HotRodx10 said:


> If it's like mine with a chipped key, without reading the code from a valid key, it will still crank, but it won't start.


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## Nut'n'Done (Nov 28, 2021)

My thoughts are,
Without knowing the mileage, just improper maintenance.
You could guess all day long and continue to throw parts at it with the same result.
This vehicle must have been throwing codes for some time now.
The codes have been
cleared for sometime as well, while still driven ill.
Now the vehicle is no longer capable or cranking, no com connection etc, for a reason. Forget getting it back into limp mode unless you have the means to do so.
IMO, it will take more $$ than the vehicle is worth to wake it up at this point.

In any event, I hope it works out.


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## raylo32 (Nov 25, 2006)

That's the nature of diagnosing these things on the Internet. All we have are the clues the OPs provide and our own experiences to draw from... usually not with the specific vehicle in question. But eventually once in awhile it works out. This one is gonna be a real challenge.



Nut'n'Done said:


> My thoughts are,
> Without knowing the mileage, just improper maintenance.
> You could guess all day long and continue to throw parts at it with the same result.
> This vehicle must have been throwing codes for some time now.
> ...


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## Nut'n'Done (Nov 28, 2021)

If I were the OP, I would be asking my friend to give me a run down on what was going on prior to this condition along with the mileage.
You can test/bench test everything the poster has thrown at this vehicle to rule them out before replacing.
I couldn't even take a stab at what could be going on at this point.
Jus' sayin.


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## HotRodx10 (Aug 24, 2017)

raylo32 said:


> Interesting. What brand? On GMs I have worked on they won't even crank. Not sure about my Tacoma since I have never had that sort of issue.


My Toyota Sienna and my son's Ford Explorer will both crank, but won't start, if the it doesn't read the chip.


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## HotRodx10 (Aug 24, 2017)

With multiple systems/components acting as if they have no power, I would take a close look at the chassis grounds under the dash, including the ground for the ECM. Many times, multiple components in unrelated systems will share the same ground.


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## Brainbucket (Mar 30, 2015)

Sounds like we have a bad module pulling down the system. Do you have a scanner? I have had the A/C control panel disable the vehicle by shorting out and pull down the system. Your going to need a scanner to see what system is up and start disconnecting modules until the system comes up.


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## Old Thomas (Nov 28, 2019)

I had a 2005 Caravan. In the first 50k miles it virtually fell apart. I sold it with 50k miles and 3 years old. What a turd. It was my last Mopar. If your 06 lasted till now you had better luck than I had.


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