Is the Enigine Coolant Temperature monitored by the PCM

[SLangone]

Your not kidding replacing that sensor was a pain. I replaced the part myself a few months ago and still have the same problem. I guess my next course of action would be to test the resistance like you have stated. Is the gauge on the sensor supose to be above the first hash mark?

 

[jhawkins]

As I recall the first mark on the gauge is 140 degrees and the one straight up is for 190 degrees. So if you have already changed the sensor try checking the voltage from the sensor connector to ground with the key in run position. Maybe you have a bad connection at the PCM. I read somewhere these model year PCM connectors had some problems, I think I saw a repair kit with special tools to change out bad terminals somewhere. You might also remove both battery grounds and then pull the connectors off the PCM and spray them with some electrical contact cleaner and them put them back on. I do not know for sure but I would think circuit has a fuse so that might be worth checking also. There have been a lot of people saying they have all kinds of trouble with bad grounds. I hope that is not the problem as they are all over the place. Sounds like you are probably going to need a good shop manual electrical diagram to trace this one.

 

[SLangone]

Sounds like a fun project!

 

[SLangone]

Update on the error code. Went to a Dodge Dealership where there was a certified diesel mechanic and told me that it was working correctly and that since I have a diesel pick-up that this error code is normal on a 1996 12 valve. What are some of your thoughts on this? Are other running into the same trouble code P0118? Side not: Congrats to TDR and other Dodge owners with Motor Trend’s Truck of the year award.

 

[Gene Heck]

P0118

I have had this truck for almost 4 years now and haven't had a P0118 yet.



Gene

 

[SLangone]

The service ticket said checked and found code in system. Vehicle not equipped with ect sensor (Federal Emissions Vehicle) Recommended removing connector for sensor due to corrosion. Customer declined at this time

 

[Gene Heck]

That's what I was saying in post 12. On a 49 state truck the sensor on the left rear of the head that is near the firewall is powered from the instrument cluster and only serves the gauge.



On an EGR engine they put a sensor on the left side of the head about mid point. This is connected to the PCM and is an input so the PCM can operate the EGR.



If your are getting a P0118 this is an emissions statement and has nothing to do with the temperature gauge reading.



I can only speculate right now but I wonder if someone bought and installed a used PCM from say EBAY for example that was programed for a California truck. If that's the case I would think the dealer should be able to reprogram it not to look for an ECT input since a 49 state truck doesn't use this as an input although the pins on the PCM are there, just not used.



Whatever dealer you went to I don't think his "certified diesel mechanic" should have told you that an error code is a normal thing. Error codes are not a normal thing if everything is working correctly. Even if they had had a glitch in the program back in the day it would have been addressed and corrected during a reflash during some visit to the dealer.



Gene

 

[SLangone]

Gene thank you so much for the help I live in Virginia and am running out of dealers to go to do you have any advice?

 

[Gene Heck]

Well a couple of questions. How long have you owned this truck? Do you know anything about the trucks history or the previous owner? Did the problem just start or was it with the truck when you acquired it? I searched through my 97 CD (I have a 96 paper manual also but the CD is easier to use) several times and except for what I suggested that the truck may not have the right PCM in it I am at a loss to suggest anything else. I don't know if a gasser PCM will operate a diesel or not because I've never tried it. The PCM in the 49 state Diesel doesn't do that much as far as the engine is concerned. It basically regulates the alternator output, operates the grid heaters, the auto shutdown relay,and a few other misc things such as the tach, water in fuel etc. However if it is an EGR engine it controls the function of the EGR between 140 and 210 deg. F. If the PCM is looking for a sensor that isn't really there and thus is an open circuit it could by default report a "high" reading. This would depend on the program statement for that part of the circuit. If this would be the case, then the EGR function would need to be turned off or the correct PCM installed.



I'm sorry if this is getting to long and confusing.



At this point and to try to save diagnostic dollars I would suggest taking all the numbers off of the PCM and see if the dealer can identify it for you to make sure you have the correct PCM.



Gene

 

[Gene Heck]

After reading through all the posts again just now, maybe JHawkins is right that the reflash is causing the problem or, maybe the PCM because of it's age is starting to get a little flaky especially if it has not been reflashed right before your problem started like his did. If all your PCM part numbers check out I would say that putting in a reconditioned PCM would be the way to go or of course just live with it as long as your mil light isn't on all the time and driving you nuts.



Gene

 

[SLangone]

So Jhawkins do you still have the error code? I know that my PCM has been reflashed by a Dodge dealer a while back too.

 

[SLangone]

This is an e-mail that the service manger had sent me thanks everyone.

#ad

 

[Gene Heck]

The email that your service advisor sent you clears up your mystery. I'm glad that he did that for you. At least you know now and don't have to worry about it. I am currently running a PCM out of a 97-49 state w/auto truck and apparently it has never had the reflash that yours has received. I have a spare PCM out of a 96-49 state w/auto that I was about to offer to loan you to see if it would "make your problem go away". That is it would prove that you don't have a wiring issue etc. I know that this spare that I have is good. It originally was in my truck. It has never had a reflash. Neither of my PCMs has ever given me a P0118.



In case you are wondering why I swapped out PCMs it is because the original that came in my truck would put the trans in limp mode when a convertor lockup switch was used. This was a program issue on 96 trucks built until 4/96 or 5/96. I forget the exact month. They developed a reflash that corrected this. My original never had this reflash and instead of taking it to the dealer and getting it done I found a 97 PCM at a good price and am currently using it.



The reason that I made the somewhat negative comment about the certified diesel mechanic is because sometimes they tend to give you a vague unclear explanation of your concern. Sometimes it makes you feel like they are just blowing you off to get you out of there. If he had produced that Star document it would have cleared up your concern immediately.



At least I can say I learned something new today.



I'm glad you issue is resolved. Good luck with your truck.



Gene

 

[jhawkins]

Yep, I still have the code and I just ignore it cause the temperature gauge in the dash indicates it's not overheating. When I was having transmission shifting problems and saw the code I really thought that it was the cause and I wasted a lot of time trying to fix a problem that did not exist. When I eventually found the cause of the shift problem and ECT code was still set, I figured it did not mean anything so I just stopped worrying about it. The only thing I could figure is the re-flash I had done must have caused the PCM to start checking the ECT, which in my truck, does not exist.

 

[SLangone]

Thank you everyone for such great help. Now on to the next thing aka KDP this will be undertaken on the 30th of this month. I also just ordered a thermostat to replace what the tech said needs to be looked into.

 

[SLangone]

Merry Christmas all. Today I fixed my gauge. It was because of a stuck open thermostat. Now it will shoot up to 180 and the gauge will go quickly down. From what I am told this is normal and nothing should be done.

Thanks again for such great help.

 

[All-Pro]

No Overdrive Upshift Problem Fixed

My name is Justin, I own a Transmission shop and have a customer with a 96 Dodge Ram 3500 4WD / 5.9L Diesel / 47RE Transmission / Federal Emissions (as opposed to California Emissions). After the transmission was built the customer complained of the vehicle not shifting into overdrive. After going in circles the customer pointed me to this thread which helped us solve the problem. Below is what we encountered and how we fixed it:

• The vehicle arrived driving and shifting fine but with no overdrive
• The only stored code was P0118- ECT Sensor Voltage Too High
• The only noticeable issue is vehicle showed it was not charging at proper voltage
• We inspected the wiring harness and determined all wires had good continuity and proper resistance and all connections checked ok
• While driving we determined the PCM was not commanding overdrive
• We concluded the problem was the PCM so we replaced it (with the Federal Emissions PCM) and had it re-flashed
• This fixed the charging issues but did not have any affect on the P0118 code or the Overdrive upshift
• We realized the Federal Emissions computer has no inputs for the engine coolant temperature sensor and disregarded the code
• We then read this forum and started closely watching the Crank Sensor on the data stream
• When idling we noticed the Crank Sensor signal would periodically drop off for a nano second and then come back up
• Consequently we replaced the Crank Sensor with the Mopar part from Dodge (part# MOP4746691)
• As soon as the Crank Sensor was replaced the truck got overdrive back
• The code P0118 ECT Sen Vol Hi remained but seemed to have no affect on the truck or shifting

If you have questions about this or other tough transmission issues please feel free to contact us at 281-205-7373 (All-Pro Transmission in Tomball, Tx)
http://www.all-protransmissions.com/

Thanks,

Justin