2017 RAM 1500, 5.7L, ~52,000 miles Continuos Overheated Mode even after parts replacement.

[GlitchMobile]

2017 RAM 1500, 5.7L, ~52,000 miles Continuos Overheated Mode even after parts replacement.

Hi everyone, I've replaced

• the water temp sensor;
• the thermostat;
• the fan clutch;
• the oil pressure temperature sensor;
• and flushed out the entire cooling/heating and engine block system;
• Burped the air out of the cooling system after refilling;
• I've disconnected the battery overnight to reset the PCM;
• I checked all the fuses, all ok;
• tested all fuses, all functioning.

The next day the truck started. Temperature slowly increased up, until the dashboard lit up to indicate engine overheating.
Upon inspection with a temperature gun, the thermostat housing and engine were only 150F .

The dashboard display indicated outdoor temperature at 95F.

Technically the engine is not overheating (OEM thermostat opens at 203F), yet the PCM thinks otherwise.

Today (23Aug2021): cold engine 89F, reconnected the battery after 24hrs of it being disconnected.
Attempted to start the engine, but the dashboard indicates an overheated engine, even though the engine is at 89F
(Visited a nearby Chrysler dealer to ask the service/repair center, if there was a secondary thermo censor on the ram and they couldn't say.)

What could be causing the PCM to misread an overheating issue?
Is there a hidden second water temperature sensor, that works in tandem with the water temp sensor?

 

[Fast69Mopar]

2017 RAM 1500, 5.7L, ~52,000 miles Continuos Overheated Mode even after parts replacement.

Hi everyone, I've replaced

• the water temp sensor;
• the thermostat;
• the fan clutch;
• the oil pressure temperature sensor;
• and flushed out the entire cooling/heating and engine block system;
• Burped the air out of the cooling system after refilling;
• I've disconnected the battery overnight to reset the PCM;
• I checked all the fuses, all ok;
• tested all fuses, all functioning.

The next day the truck started. Temperature slowly increased up, until the dashboard lit up to indicate engine overheating.
Upon inspection with a temperature gun, the thermostat housing and engine were only 150F .

The dashboard display indicated outdoor temperature at 95F.

Technically the engine is not overheating (OEM thermostat opens at 203F), yet the PCM thinks otherwise.

Today (23Aug2021): cold engine 89F, reconnected the battery after 24hrs of it being disconnected.
Attempted to start the engine, but the dashboard indicates an overheated engine, even though the engine is at 89F
(Visited a nearby Chrysler dealer to ask the service/repair center, if there was a secondary thermo censor on the ram and they couldn't say.)

What could be causing the PCM to misread an overheating issue?
Is there a hidden second water temperature sensor, that works in tandem with the water temp sensor?

You could have saved yourself some money had you connected a scan tool to the truck. A scan tool is like a window for us to be able to see what is going on inside.

With a scan tool you can tell whether or not the PCM is reporting incorrect data or if a sensor is reporting incorrect data.

With a good scan tool you can see the bussed inputs and outputs from each control module to see if each module is sending and receiving the same information.

I wouldn't do anything else to the truck until I had a scan tool connected and someone who knows what they are looking at to decipher the data.

 

[GlitchMobile]

I connected an Autel MaxiCOM MK808 and it could not communicate with any module, until the overheated engine fault was erased by disconnecting the battery overnight.

Then the scan gauge confirmed a history of communication faults amongst all modules.

 

[Fast69Mopar]

I connected an Autel MaxiCOM MK808 and it could not communicate with any module, until the overheated engine fault was erased by disconnecting the battery overnight.

Then the scan gauge confirmed a history of communication faults amongst all modules.

You were unable to communicate with any module on the truck until after that battery disconnect occured?

Do you have an actual "Scan Gauge" that will connect and communicate with the PCM?

What does the Autel scan tool show for engine coolant temp in the data stream?

 

[huntergreen]

You could have saved yourself some money had you connected a scan tool to the truck. A scan tool is like a window for us to be able to see what is going on inside.

With a scan tool you can tell whether or not the PCM is reporting incorrect data or if a sensor is reporting incorrect data.

With a good scan tool you can see the bussed inputs and outputs from each control module to see if each module is sending and receiving the same information.

I wouldn't do anything else to the truck until I had a scan tool connected and someone who knows what they are looking at to decipher the data.

What's a good scan tool for the average guy ?

 

[caulk04]

I connected an Autel MaxiCOM MK808 and it could not communicate with any module, until the overheated engine fault was erased by disconnecting the battery overnight.

Then the scan gauge confirmed a history of communication faults amongst all modules.

That's info in and of itself. Wiring issue, be it a ground problem, damaged wire or even the possibility of a 'bad main board'. That last one is for fans of South Main Auto on YouTube.

 

[Fast69Mopar]

That's info in and of itself. Wiring issue, be it a ground problem, damaged wire or even the possibility of a 'bad main board'. That last one is for fans of South Main Auto on YouTube.

You are absolutely correct. With a history of "loss of communication" DTC's I would verify that every module was powered up and on the bus. Then I would verify communication by toggling inputs and outputs that are bussed to another module to see if the information was being sent and received properly.

 

[Fast69Mopar]

What's a good scan tool for the average guy ?

I have been a mechanic for a long time and have used a multitude of scan tools. I always tell my customers or new mechanics the same thing. By the absolute best that you can afford. Do your due diligence and shop around and find the one(s) that will give you the best bang for the buck. Look for scan tools that have bi-directional control capabilities. Look for scan tools that have the capability to communicate with multiple modules.and not just the PCM. Find one that can communicate with the PCM, ABS, Airbags, TCM and as many as possible.

There are some good Bosch scan tools. Innova has a couple with bidirectional controls. One I personally use daily is this one...the link says amazon.com but it takes you directly to the one I am referring to..

Amazon.com

I got a really awesome deal and even at $799 it is still a solid price point for the capabilities that it has. I have a SnapOn Triton D10 and a Verus Edge that I use for more in-depth diagnostics but the one I linked is a very good daily use scan tool.

 

[crackerjack1957]

I have been a mechanic for a long time and have used a multitude of scan tools. I always tell my customers or new mechanics the same thing. By the absolute best that you can afford. Do your due diligence and shop around and find the one(s) that will give you the best bang for the buck. Look for scan tools that have bi-directional control capabilities. Look for scan tools that have the capability to communicate with multiple modules.and not just the PCM. Find one that can communicate with the PCM, ABS, Airbags, TCM and as many as possible.

There are some good Bosch scan tools. Innova has a couple with bidirectional controls. One I personally use daily is this one...the link says amazon.com but it takes you directly to the one I am referring to..

Amazon.com

I got a really awesome deal and even at $799 it is still a solid price point for the capabilities that it has. I have a SnapOn Triton D10 and a Verus Edge that I use for more in-depth diagnostics but the one I linked is a very good daily use scan tool.

Thanks @Fast69Mopar..........picked 1 up for $700 at obdprice.com with $20 off code
PR9NWA02J3Y5

【2-Year Free Update】Autel MaxiPro MP808S Kit Automotive Diagnostic Scan Tool with Bi-directional Control and Full Set Conneter Same as DS808k (Upgraded Ver. of MP808/MP808K)

100% Original Autel MaxiPRO MP808S Kit OE-Level Diagnostics Tool Comes with A Full Kit Adapters, Full System Diagnostics with Bi-Directional Control, OBD2 Scanner with 18 Special Features, AutoVIN, Key Coding, Actuation Tests, Same Functions as DS808, MS906. HK/US/UK Stock, Free Shipping, No Tax.

www.obdprice.com

 

[GTyankee]

I just bought a simple scanner
It tells me what is wrong & that lets me know if i can fix it myself or someone smarter than i

I just have an ACTRON scan tool
It at least reads ABS & Air Bags
picked it up at Pep Boys for something like $220 around 3 years back

 

[Fast69Mopar]

Thanks @Fast69Mopar..........picked 1 up for $700 at obdprice.com with $20 off code
PR9NWA02J3Y5

【2-Year Free Update】Autel MaxiPro MP808S Kit Automotive Diagnostic Scan Tool with Bi-directional Control and Full Set Conneter Same as DS808k (Upgraded Ver. of MP808/MP808K)

100% Original Autel MaxiPRO MP808S Kit OE-Level Diagnostics Tool Comes with A Full Kit Adapters, Full System Diagnostics with Bi-Directional Control, OBD2 Scanner with 18 Special Features, AutoVIN, Key Coding, Actuation Tests, Same Functions as DS808, MS906. HK/US/UK Stock, Free Shipping, No Tax.

www.obdprice.com

Yeah man. I was pleasantly surprised with this kit. One of the reasons I liked it over so many others was for the vehicle connectors that it comes with. The MP808 or the DS808 do not come with as many.

The setup is pretty simple and everything is broken down like an app on your phone so it's easy to use.

 

[huntergreen]

I have been a mechanic for a long time and have used a multitude of scan tools. I always tell my customers or new mechanics the same thing. By the absolute best that you can afford. Do your due diligence and shop around and find the one(s) that will give you the best bang for the buck. Look for scan tools that have bi-directional control capabilities. Look for scan tools that have the capability to communicate with multiple modules.and not just the PCM. Find one that can communicate with the PCM, ABS, Airbags, TCM and as many as possible.

There are some good Bosch scan tools. Innova has a couple with bidirectional controls. One I personally use daily is this one...the link says amazon.com but it takes you directly to the one I am referring to..

Amazon.com

I got a really awesome deal and even at $799 it is still a solid price point for the capabilities that it has. I have a SnapOn Triton D10 and a Verus Edge that I use for more in-depth diagnostics but the one I linked is a very good daily use scan tool.

Thanks for this .