I have a lot of experience working on my Dodge, Chrysler, and BMW vehicles but this is a new problem to me. My Wifes 01 T&C 3.8L with 106,000 on it suddenly went nuts. DTC P0202, P0118, P0107, P0108, P1478. She could not get it to leave the parking lot at work. I swapped cars with her and drove it home, at first it would barely run, but as it warmed up it was fine, to the point of easily running at 70 on the interstate. I cleared the TCs and re-started it and it still showed P0107 and P0108. I thought that BOTH Low and High voltage error must mean the MAP sensor was bad. Replaced that, and it still runs badly and throws all the above TC's again. I read on the Dodge forum that sometimes the wiring harness fuses together, I'm checking for that now, so far no problems I can see with that. HELP! I need this van Friday to take our youngest to college.

 

look at the ign coil behind the coil will be a connector in that area is where u want to look for the wires melted together.

 

Thanks for your fast reply. Just finished lunch and ready to tear into it.

 

Yes, that is the problem, all 10 wires melted together. I hope I didn't fry the ECU, what a mess! I'll post some pictures to the forum. I think the best fix is to cut each wire and slide some heat shrink tubing down each one and re-connect. Wrap the whole thing back in some aluminized insulation I have. Any other ideas?

 

Well the wires were certainly a mess, all 10 of them had lost their insulation. The actual conductors were good. Now however the engine still runs just as badly and I still get a P0108 trouble code. I wonder if the bad wiring fried the new MAP sensor? I would think that was a good possibility.

 

Scott, I have fixed these before and they leave running fine, then a couple weeks later they come back with a fried injector or coil driver....PCM. It just depends on how long you run it with all those shorts going on.

 

Thanks, That is what I'm afraid of! I probed the connector with the ignition on, MAP sensor disconnected and the center pin is ground, the Pin on the right is 4.87 V and the one on the left is 4.96 V. Left and right being referenced with the clip of the connector up. According to a test protocol I found on easydiagnostics.com for testing the MAP sensor, the signal pin with the sensor connected should be 4.7 volts at ambient pressure. (The sensor on that web site was not exactly the same as mine so I am not sure of the pin numbers.) I also checked it with my vacuum gauge and could not get a reading change as I applied vacuum. So all this to say that I am not sure if the new sensor got fried, but it seems to me that there should not be any voltage on the signal wire with the sensor disconnected which makes me think the ECU may have been hit too. Where are you in TN? I may just have it towed over there soon. Scott

 

It is completely possible the map sensor was damaged by a "Backfire" or ruptured diaphragm, and not necessarily electric "Spike"......

Just food for thought.....

As for the variation in Voltages.... Any host of variables can cause this, from the Breeze blowing down the driveway, to the batteries in your meter.....Typically, anything above 4.5 is close enough to 5 as far as your pcm is concerned.... A quick word....Dont check the ground circuit with a Dvom.....use a bulb type circuit tester..... Dvom impedance isnt high enough, so any "Resistance" issues in the ground circuit wont be detected. If you load the circuit with a BULB.....you will immediately notice the "Dimmer Than Normal" lamp.

 

Sorry for the delay on updating this issue. Apparently the wiring did destroy the new MAP sensor. I stopped by a U-pull it last week and for the $2.00 price of admission pulled a MAP sensor off a 3.3L engine. Though mine is a 3.8L. I was fully expecting the van to not start, not run, but It fired up fine! Also while I was away on business I left the - battery cable disconnected and a charger on the battery, as it would not crank the other day when I was working on it. So, new (used) Map, Fully Charged Battery, or leaving it dead for 4 days... one or all of those things fixed it. After of course opening the wiring harness and fixing the definitely shorted 10 wires.