Trying to send some long distance help to a friend who's '03 Grand Caravan failed to start yesterday. They were at a restaurant and went to leave and the engine wouldn't turn over. Lights all turn on as normal, fan blows, but no starter. They ended up taking it to a shop nearby, and they told them it needed a new pcm. I was told from an outside source and in my experience the starter would still turn over with a bad pcm. They say they switched the starter relay and tested the starter, starter was fine and the relay made no difference, they also tried starting it neutral to check the neutral safety switch. I told my friend to tell the mechanic to pound on the dash and try it, but I'm doubting they'll believe them and do it. Anyone have any other ideas? I'm really hoping to avoid driving 4 hours one way tomorrow with my trailer to pick them and the van up. Thanks for your time.

The PCM can prevent the starter from cranking. The PCM provides the ground to the starter relay coil. Without the ground, the relay contacts won't close keeping power from reaching the starter solenoid.

Thanks for the info. RIP. So if that is the case, jumping the relay with the key in the run position should start the car, correct? Or is it more likely that more is wrong with the PCM than that and it still probably won't run? I did see that the computer provides the ground in another thread, but I was looking for confirmation. I'm really trying to eliminating a trip down there with the trailer and back full.

Went to Madison today to pick it up. Got home and tried pounding on the dash, no change, removed the relay and jumped to the starter solenoid lead from the power lead, engine turned over, but no start. I'm leaning towards the shop being correct about needing a pcm. Any one have any particular places to check? I'd prefer a rebuilt one vs spending on the new one. Also, is there any other way to verify that it is the computer? It doesn't supply the ground to the relay when turned to start, but the ignition sends the trigger power to the relay. If anyone's had their harness repaired, as opposed to the PCM replaced, could you clue me in on where the bad spot was? Thanks a ton. Jared

You will have to have the VIN and mileage programmed into the pcm before it will run the vehicle. You can use a test light at the relay. First, take out the relay and see if the 86 pin has power key on engine off. If no check the ignition switch and wiring to the fuse box. If you do have power, jump across 86 and 85 have someone turn the key to start and see if the test light lights. If it does then your problem is not the computer. If it doesn't, C1 pin 31 dark green/orange at the PCM is the control for the relay, backprobe and clip the test light to the + side of the battery and do the same thing again, if it lights it is wiring, if it doesn't you may have a bad PCM. C1 pin 38 yellow, backprobe and put the test light on there with the other end on ground. Try to start the van. If it lights the PCM is getting the signal to command the starter relay. If it isn't lighting, you have a wiring issue or a bad ignition switch.

Thank you very much, exactly what I was looking for. I checked pin 31, no light. Checked pin 38, test light lights. Also noticed the fuel pump doesn't turn on either, check engine light comes on when the key is turned on, but there are no codes stored, no even from when I had it cranking from bypassing the relay. What was the name of the place to get the reman computer/have mine reman'd?

The check engine light coming on is just a bulb check. Your best bet for a computer is actually the dealership. I've had a lot of problems with reman computers and the dealership is also the only place I know of that can program the vin and mileage into the computer.

Thanks again, RahX, part of the reason I ended up going and getting the van was because the first shop said the computer was backordered and might not arrive for up to a month. I don't know for sure, but I'm guessing it was coming from Dodge. I ended up buying a reman from a place I found off of ebay, had very good feedback, hopefully it'll work out. I'll post back the results on friday, which is when it's supposed to arrive.

Well, it took a few extra days, 5 to be exact, to get the computer, but I finally did, and everything is like new again. Took a few trips to get the trans shifts back to normal, but it's great now and the owners claim it gets better mileage, as they took it up north the second i returned it to them. I'm not sure about their mileage claim, but it does work, and that's the important part. Got the computer from ACE (autocomputerexchange) for $279, counting the extra $30 for 2nd day shipping, with a life time warranty. Thanks again everyone.

So ACE reprogrammed it with the VIN and mileage?

Yep, I gave them the VIN, the original computer's part number, and the exact mileage (not sure how close they need), and had to send the original back w/in 10 days to receive the lifetime warranty. The only thing I'd complain about is that it took them 3 days to ship, then 2 days for my 2nd day shipping to get it to my house. Normally not a big deal, but I was in a serious time crunch on this project.