I Messed Up My Truck Installing Trans Temp Gauge

[Delano1981]

I may have screwed up my 2007 Ram 1500 Hemi. I tried installing a transmission temperature gauge from max Tow. Followed all the instructions using 2 add a circuits for the switched power and light circuit for the gauge dimming. My big mistake was that I forgot to disconnect the negative power from the battery. The truck ran fine for a while and the gauge worked fine. Then all of sudden the truck stalled while I was driving, and it was very hard to start and ran horrible after starting. I limped home and immediately disconnected all wiring from fuse box and and gauge, and it ran great for a day. Now this morning same thing, hard to start and runs terrible. I did an engine code scan and got P0520 Oil Pressure sonsor , P0335 Crank position sensor, and P0122 throttle position sensor voltage low. I have a superchips tuner so I tried reflashing the computer and that didn't work. I hope I didn't fry the PCM. Any ideas ?
Thanks

 

[Delano1981]

Ok, I think I know what happened. I used a bare wire to snake the transmission sensor wires back behind the engine down to the passenger side of the transmission. I forgot to disconnect the battery and the wires were connected to the Max Tow gauge and the gauge was completely hooked up with all power connections connected. Dumb mistake. Do you think the PCm is damaged?

 

[SYKRAMMAN]

Have you checked all fuses?

 

[droopie85gt]

What circuits did you hook the add a circuit fuses to?

 

[Delano1981]

Yes, I checked all fuses. They're good. I used Cavity 23 engine control module for switched power, and cavity 14 Park Lamps Left for dimming circuit. For constant power I connected directly to battery positive. Now looking at what I did, it looks more and more likely that I damaged the ECU.

 

[Delano1981]

The more I think about it the more things I remember about the installation. When I was done installing the gauge, it ran fine and the gauge worked perfectly for a day. Then I checked the transmission fluid and when I closed the hood it stumbled and the engine almost stalled. The next day on the way to work it just completely died at a stop sign. I wasn't far from home so after barely getting it started I limped home. I disconnected all the add a circuits at that point and it ran fine all the rest of the day. The next morning it had the symptoms again, would barely start and threw the 3 DTC's mentioned in my first post and that is where it stands right now.

 

[justin13703]

I hope you get it figured out, I have no pointers for you though. Electrical stuff can be tricky especially if you tap into something involved with the ecm. I try not to go into the engine bay to get power for aftermarket stuff for that reason. There’s plenty of constant/switched power/grounds in the cab of the truck.

 

[Delano1981]

Update on my electrical problem. I took it to a shop for diagnosis. It was the crankshaft position sensor and a couple of the wires were melted together. It runs now without any trouble codes. But, it doesn't feel right. it doesn't drive like it used to. It's sluggish, and it is hard to describe but it just doesn't coast easily like it did before. I went on a camping trip pulling my travel trailer this last weekend and it struggled more than usual pulling it. There are no trouble codes, and the problem is very subtle and you would have to drive it daily like I do to be able to feel the difference, but it is very noticeable to me. I am wondering if there is a transmission problem or something. I don't know.