Hello people,

I am getting a CEL but when I check for codes there is nothing there. I got a CEL a couple of weeks back and took it to a garage. They told me a code came up for Thermostat Full or something to that extent. The mechanic asked me if it had been heating which it had not. He cleared the code and all was well unitl this weekend.

This has happened twice since I have owned the truck. The first time I had pulled my 5er up in the mountains and done a little running around without the 5er hooked up, early the next morning we heade home with the 5er hooked up and within a couple of miles the CEL came on. That is when the code came up that the mechanic pulled. This time I pulled a 6k pound cargo trailer to Missouri from Colorado and all was well. I done a little running around the next day. The third day I was headed back to Colorado with the same trailer in tow and withing a couple of miles the CEL came on. This time I tried to pull the codes with the key but none were available, it shows done. On both instances I pulled with the Tow/Haul on, my 5er is about 9K and the cargo trailer is under 6k. The temp never went above normal. With the 5er I used the e brake but not with the cargo trailer. On both instances it was very early in the return trip when it was cool out and the temp was still on the low side of normal with the Tow/Haul on.

Any thoughts befor I take it in to have the light shut off?

Thank for your help.

Jeepman

 

Sound like your DPF is filling up and you may start to have EGR valve and Turbo issues. I'd take it in and get it looked at and addressed (especially with a warantee). Then, I'd always drive it with the E-brake on and in T/H... Then, I would delete the DPF and EGR and never have to worry about these things again.

 

That's not what I wanted to hear. No warranty so maybe the best thing to do is delete and keep the parts for that once every two year inspection. That won't fix the turbo if that proves to be the problem.

 

What codes are you getting?

If its on again, and you dont have a code scanner, you can do the key turn method, or go to Autozone or O'Reillys and they can read it.

 

Good Morning Blake, I was not getting a code from the key switch method. I took the truck to Advanced Auto and had the code read. It is P0128, defective thermostat, coolant temp sensor or low fluid. The thermostat does not sound quite right because the truck warms up and does not go past midway on normal on the gauge, Low fluid is not the case so I can only guess a sensor. The funny thing is that both time this has happened it was after towing in a fairly heavy rain and then a few days later towing again on a cool (60-70 degrees) morning. And both time within a couple of miles of taking off.

I have not been able to find a sensor. I will admit for fear of price I have not tried the dealer. Where is this sensor on the truck?

Sorry for the lengthy explaination.

Thanks for the response.

 

The light went out. I must need to clean the battery cables, maybe check the connection on the sensor.

 

Id check the sensor connection for corrosion, and the battery connection for corrosion and or being loose.

If it self cleared it may have just been a ghost in the machine, especially if its performing ok now.

 

Thanks for the reply Blake. I will check these connections. The idea of a ghost was my first thought but this is the second time this has happened and both time were after driving in the rain one day and then taking off again a couple of days later early in the day. Almost like it allowed the rain to dry but then drove when the humidity and dew were higher than normal.