Hey guys, today around 10 am i drive through about 36 inches of water while scoping out an area for a military exercise here in Italy. Later on went to run some errands, truck started and ran fine. Drove it about 5 miles, parked to run in some where and went to leave and all of a sudden I get some intermitent idleing and shutoffs. Tried cranking, it would crank back up, put it in drive and boom, it would die again. Did this about 4-5 times and now it wont start. Now the engine light stays on, tried to pull codes but it doesnt sense I have the key in the on position so guessing its not seeing the PCM. Disconnected batts, I pulled the PCM, removed my DP tuner chip to eliminate it as the culprite, and noticed the PCM pins had a small amount of moisture sitting inside the port. Dryed it the best I could, slapped it back in and no change. Pulled the PCM and have it taken apart to remove any other moisture overnight. Also pulled all the fuses under the steering wheel as well. Had to leave the truck at the place I was at inside thier locked compound.

What do you guys think this could be? Open to all suggestions. Hoping its a simple fix since to avoid it being down for weeks waiting for parts over here.

 

That's a lot of water, WOW. What year is the truck? I'm guessing the WTS light still comes on, if so PCM probably OK. Just guessing with limited information but it sounds like the IDM might have water in it, with the symptoms you described. did your code reader work before this happened?

 

Its a 2002. Pretty sure the WTS light still worked fine but gonna doublecheck tomorrow. My code reader did work, as I just used it recently. How can I see if the IDM has water in it? Where is it located?

 

The IDM is in the drivers side wheel well above the cover, but on the outside of the fender.

Skip ahead to about 1 minute into this video.

 

Thanks for the vid���� I would have never found it on my own lol. Anyone know how to check the IDM? Also, if either the PCM or IDM are toast, looking for a reputable place to get a replacment.

 

Pull the IDM and shake it. The OE ones had a vent hole in the side with a waterproof membrane (ha!) that often allowed water intrusion. If water drips out the hole there ya go. With Torque Pro or similar you could pull the codes, but it seems like these water intrusion scenarios produce lots of spurious codes, might not lead anywhere. Worth a shot I suppose.

I saved wet electronics before by warming them for a couple hours with a hair drier. But since swapping the IDM is a pain I'd prefer to replace it rather than attempt repair.

I have 3 trouble free years on a stock reman IDM from RAE electronics, $135. Now they also have a high voltage "performance" version for $400.

 

Thanks for the info! I will give this a try today for sure.

 

Update:

WTS light does not go off. But the fuel pump does cycle. Removed the PCM overnight and dried it with a hair dryer. Inspected it and everything appears good( no dark or burnt components). Put PCM back in and same issues. Cranks fine. Code reader still doesnt see the PCM. Gonna try and remove the IDM to inspect it now.

 

Did you look at the CPS? With 3 foot of water It could of came loose. I'd pull that a part, check closely and see what you find. Cheap fix even if you have to replace.

 

I will look at that today too. Good call

 

CPS wasnt loose and changed it out for a new one I had for good measure but no change. WTS lifht and CEL light are still on. Code reader still doesnt see the PCM.

 

It was worth a shot. You did check all wiring to the CPS also? Fuel pump is on the frame rail as well. Is it pumping? I had some buddy in Vegas dump something in my fuel tank that keep taking out my pump. After three times I had the tank dropped, fixed, and know more problems. Yours sounds like electrical but I'd check pump as well.

 

I will inspect the wiring to the CPS to be safe. I am positive this problem is electrical due to the way it acted and the symptoms its displaying. The fuel pump is pumping as well.

Anyone know a decent place where I can get replacement relays online to eliminate those as the source?

 

Think your issue might be a shorted sensor somewhere due to water intrusion. Most sensors use what's called VRef which is +5 volts supplied by the PCM. You can measure this with a volt meter at most sensors, MAP is probably the easiest. One of the three wires will be ~ 5 volts. The other thing you can do is simply unplug all three wire sensors and see if the WTS light will cycle normally. If so plug one at a time in until the problem returns. If VRef is missing the PCM won't boot and WTS light will stay ON. Personally I would start with the EBP sensor and go from there.

 

Thanks for the suggestion. Sounds like a good plan. I will start this tomorrow. I did check unplug the EBP sensor due to another thread I found, but unplugging it made no difference

So I have the MAP sensor on the list to check. Anyone have a good list and locations of sensors to check?