P-0118, ECT Voltage High. Make any sense to you?

 

this is gunna be a innovative step, u reset the pcm , and the code poped back up, theres something there , Have to ask cause this happened to me , you dont have a jet performanc chip do you? Mine shorted out threw that code and once i replaced that sensor it threw tps code, then Iac , till i relised that Chip died.

Anyway back to the steps , Hook one wire from the signal in with the 5v+ line to the sensor then hook ur volt meter from the other lead on the sensor to a ground. That will complete the circuit. if you see exactly 5volts the sensor is bad. Thats the tan/black wire with the Power, Black/blue is ground. Im sure you know , but key on engine off.

EDIT: Look for a pink single wire connector somewhere in that location

 

Haynes states that temp gauge goes to the sender through a 18 gauge violet/yellow wire

 

I did the reset and it popped back up, yeah. I have not modded the truck, to answer your second question.

I'm going to call it a night on crawling around in my engine compartment and follow your instructions with fresh eyes in the next couple days. As soon as I find out what's up, I'll report back.

Again, thanks a million for all the real-time assistance on this. Let's hope we're nearing the end of this issue.

 

Yeah , No problem. Post on your findings. Lets see if we can rule out the ECT and hope you can get your truck running good again. Im in school till 2:30pm EST, I then can aid from work everyday so i apolgize if its a little slow to respond earlier in the day.

 

maybe its the guage's fault?

 

have your tried a gauge/cluster self test?

If your truck has a digital odometer it should work. Here's how you do it:

Hold the odometer trip meter button (little skinny button that sticks thru the plastic cluster face) in and then turn key to on, but don't fire the engine. Continue holding the button in until odometer reads CHEK, and then release it. The cluster will self test, turning all lights on, and then sweep all gauges to about 1/4, then 1/2, then full. See how your temp gauge acts.

 

I'm going to try the gauge reset later tonight. Just wanted to say thanks again, and to let you guys know I'm on hold for a bit with the rest because it's back to being quite cold over here in Chicago, so I'm waiting for a day when I can do some work when the sun's up.

 

We`re still here , waiting to help you to get it back on the road.

 

So, the good news first: My temperature gauge is back to normal, and the truck's running great.

I was able to borrow a scan tool so that I could watch the voltages being read by the computer. The ECT Sensor was reading 5.0 Volts, meaning the voltage wasn't being affected by the scanner. To eliminate a short somewhere, I jumped the two terminals in the wiring harness together, which caused the computer to read 0.0 Volts. So, good there. No short.

To eliminate the possibility that sensor itself was bad (it's brand new), I picked up another one, connected it to the harness, and put a flame on it while watching the voltage. No change. So, I'd narrowed my problem down to the harness itself. I was able to get clean connections in the harness with the multimeter, so it was my last thought rather than my first.

I could tell there was some play in the connectors inside the harness, as I was able to move them up and down. My assumption is that when the harness was pressed down onto the sensor, the connectors were being forced away from the terminals on the sensor itself.

Not being able to locate a 2nd Gen Ram in a local junkyard, here was my fix: I cut the plastic off the ECT sensor, exposing the electrical terminals. I found two electrical connectors that fit tightly on the terminals, and, adding in some new wire as well, cut off the old wiring harness and soldered the connectors in place. Slid them on to the sensor, fired her up.

Check engine light went off. Gauge came to life. Truck purrs like she ought to, and hasn't caused me a single problem in four days. Thank god.

Last note: The mystery of the missing ECT SENDER continues. Thankfully, I don't need one. I took the truck by three different dealer techs, all of whom went to the driver's side of the thermostat housing, found nothing, and said, "Oh yeah, I seem to remember there being some year where they moved them. Huh. Never seen it." No one knows. I've looked at every schematic, every parts list, etc. Half the time they say it should be there, half they time it's not mentioned. I know it's in there, because the computer reads from it. The two-wire sensor that I speak of above goes to the gauge, confirmed by voltage readings and gauge performance.

To anyone who may have this problem in the future: Check those harnesses. I spent an inordinate number of hours messing with this, and the final fix took all of five minutes and had crossed my mind early on.

To anyone who does not have the second unit on the driver's side of the thermostat housing, either let us know where you found it, or hold on tight until I can. I'm not giving up the chase.

Thanks again to everyone who stuck with me on this and offered help. You guys are fantastic, and I'm sure I'll be back soon.