2015 6.4L - No coolant temp and service electronic throttle message

[ngiovas]

I have a 2015 Ram 2500 with a 6.4L engine.

Last weekend I had about 2 hours left in a 20 hour round trip (all highway) and the check engine light came on and I got a "service electronic throttle" message on the cluster with the red lightning bolt. I noticed my coolant temp gauge was not on and the coolant temp on the digital readout was "--".

I pulled over and nothing seemed to be overheating, so I continued driving with no issues (but still no temp reading). I pulled the codes when I got home and there were two. 1 for coolant temp and 1 for electronic throttle.

I ordered a coolant temp sensor, but then realized I don't know where it is located on this vehicle. I had just assumed it would be near the top of the block, but I don't see it. With the electronic throttle error, I'm not convinced that this is the problem, but thought I would give it a try. Can anyone tell me where the sensor is located?

Also, has anyone else had this issue? Any ideas what may be causing it (if it isn't a temp sensor)? My basic warranty is up, but my drivetrain warranty is still in effect. I'm not sure that this issue would be covered though.

Any help would be greatly appreciated.

 

[Hootbro]

What were the actual codes?

 

[Burla]

heres the 5.7, dont know about the 6.4

 

[Hootbro]

Attached are the schematics for the cooling and throttle control system. If both issues happened at the same time, the only commonality is the PCM.

Cooling system is the simpler of the two and I would troubleshoot that one first and it may lead to the other issue with the throttle control system and a possible connector, corrosion or wiring issue at the PCM. The cooling sensor and the throttle body (non pedal) side both go to the same C2 connector on the PCM.

 

[Burla]

Read this thread, may be a safety issue related to this, and clearly you are not the only one.

 

[ngiovas]

What were the actual codes?

Sorry, didn't have the codes with me when I originally posted (knew I should have included). Codes were (new one now):

Current: P2181 Cooling System Performance

Pending: P0128 Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)

Stored: above 2 faults plus - P0221 - Throttle/Pedal Position Sensor/Switch "B" Circuit Range/Performance Problem

 

[ngiovas]

Read this thread, may be a safety issue related to this, and clearly you are not the only one.

I already had the cruise control reflash performed a few months ago. In addition, I have not experienced any throttle issues at all (surging, delays, etc.). Everything on the truck is operating normally with the exception of the temp gauge occasionally not reading.

 

[ngiovas]

heres the 5.7, dont know about the 6.4

I saw this video, but it is not in that location on the 6.4L. I looked around and was not able to locate it, but I didn't want to start removing a bunch of stuff because I didn't have a lot of time yesterday when I was working on it.

 

[ngiovas]

Attached are the schematics for the cooling and throttle control system. If both issues happened at the same time, the only commonality is the PCM.

Cooling system is the simpler of the two and I would troubleshoot that one first and it may lead to the other issue with the throttle control system and a possible connector, corrosion or wiring issue at the PCM. The cooling sensor and the throttle body (non pedal) side both go to the same C2 connector on the PCM.

Thanks Hootbro. I will check the connector to see if there are any signs of corrosion. I am still hunting for the coolant temp sensor so I can also check that connector.

 

[Hootbro]

There is another thread around here, but I just remember the sensor is installed in to the thermostat housing on 6.4's.

https://www.ramforum.com/threads/ch...n-cooling-temperature-gage-not-working.131614

 

[ngiovas]

There is another thread around here, but I just remember the sensor is installed in to the thermostat housing on 6.4's.

https://www.ramforum.com/threads/ch...n-cooling-temperature-gage-not-working.131614

I saw something that said that as well, but a friend of mine has a service manual for a 2014 6.4L that says the following:

6.4L

Note: the temperature sensor is located on the front side of the water pump.

1. Partially drain the cooling system. Refer to STANDARD PROCEDURE.
2. Disconnect the electrical connector from the engine coolant temperature (ECT) sensor.
3. Remove the ECT sensor from the water pump assembly.

I'm not sure if the engine changed in 2015? He said there was no diagram, but the Rock Auto site shows this picture of the water pump for a 2015 6.4L. I can't tell if that is a hose barb on the bottom left of the picture or a coolant sensor. I think it is a hose barb which would lead me to believe the 2014 engine may have been different.

 

[jdfranklin]

I’m having the exact same issue. Any progress?

 

[stihlyourface]

I’m having the exact same issue. Any progress?

Me too, what did you guys do to solve this?


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[ngiovas]

Me too, what did you guys do to solve this?


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My issue went away after a couple of days and never returned, so don't know the cause or the solution. I wish I had better info.

 

[sandawilliams]

I have a 2015 Ram 2500 with a 6.4L engine.

Last weekend I had about 2 hours left in a 20 hour round trip (all highway) and the check engine light came on and I got a "service electronic throttle" message on the cluster with the red lightning bolt. I noticed my coolant temp gauge was not on and the coolant temp on the digital readout was "--".

I pulled over and nothing seemed to be overheating, so I continued driving with no issues (but still no temp reading). I pulled the codes when I got home and there were two. 1 for coolant temp and 1 for electronic throttle.

I ordered a coolant temp sensor, but then realized I don't know where it is located on this vehicle. I had just assumed it would be near the top of the block, but I don't see it. With the electronic throttle error, I'm not convinced that this is the problem, but thought I would give it a try. Can anyone tell me where the sensor is located?

Also, has anyone else had this issue? Any ideas what may be causing it (if it isn't a temp sensor)? My basic warranty is up, but my drivetrain warranty is still in effect. I'm not sure that this issue would be covered though.

Any help would be greatly appreciated.

This happened to me a couple of years ago and cleared up in a few miles. Just yesterday (10/18) it happened again while towing. After 100 miles to get home it had cleared the throttle light and temp gauge came back. I would give it a few miles and see if it clears and if not pull the battery cable and let it reset the computer. Just another phantom issue with our Rams.

 

[stihlyourface]

Mine actually cleared after leaving the truck sitting overnight lol


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[AVictah]

I found this group looking for a solution for this very problem. I have had all the same issues as everyone else, but I will add that I have noticed that it happens only when it's below 20 degrees out. I tried cleaning my throttle body, I've replaced the temp sensor. I've had it magically reset after sitting for a night. I bought the truck new in 2015, this has happened to me three other times. It has become dramatically worse since driving in a snowstorm just this past Sunday. Now every time I drive its happening. This morning after driving to work in 7 degree weather with no heat I said that's enough and gave in to use my extended warranty. I've been in denial that I may need to use it, haha. If anyone is still interested, I will let you guys know what happens.

 

[ngiovas]

Yes, please keep us posted.

 

[AVictah]

Got it back. So they were able to replicate the issue and replaced the thermostat along with the housing. They also replaced a throttle control sensor (have no idea what/where it is) and flushed the coolant incase there was debris in the fluid. I got to talk to the tech that did the work and he said there were two codes, one had him replace the thermostat and the housing that had a small crack that was causing a very small leak which made the coolant level to go just under the minimum level and trip that sensor as well. He said the other code was for a faulty throttle control sensor so that was replaced as well. If it acts up again, I will update. Hope this helps.

 

[Montanabadfish]

Did the new thermostat fix your issue? Hitting 20s here in MT and this issue has started again for the winter. 30 degrees and warmer and no issues.