engine light/ fan running fast

[Lifeisgood72]

New to the page, searched forums and cant find an exact match to my problem. I have a 2021 3.6 wrangler rubi. Bought it with 35k miles form an out of state dealer. Within a couple thousand miles, had a check engine light with a P0118 code. Took it to the dealer, was informed my thermostat needed replaced. Had it replaced under limited warranty. Received it back and with in a week or two , same light, same code and I could intermittently smell coolant when I stopped. However, the night the light came back on, I was on my way home and left it in the driveway. When I went back out the next day, I cranked it, light came on, I went to the store. When leaving the store, I decided to take it to the dealer. But when I cranked it, no light. This went on for another week. The light came back on after a week and i then took it to the dealer. They stated I needed a new battery. I took it to another store and had them replace with a new battery. However, I still have the same check engine light come on, stay on for a day or so and then goes off. It has progressed to intermittently coming on while I am driving. But if I crank the jeep on and off a few times, the light will go off and doesn't seem to affect the driving. Also, my code reader doesn't read any codes with the light on. Today, it sputtered when I tried to crank it on 2 attempts. On the third attempt, I applied the peddle and it cranked up. When I got home I shut it off, and cranked it again twice without a problem. This is my first jeep and I am Jeep ignorant. Any ideas.....

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[bmpcamry09]

New to the page, searched forums and cant find an exact match to my problem. I have a 2021 3.6 wrangler rubi. Bought it with 35k miles form an out of state dealer. Within a couple thousand miles, had a check engine light with a P0118 code. Took it to the dealer, was informed my thermostat needed replaced. Had it replaced under limited warranty. Received it back and with in a week or two , same light, same code and I could intermittently smell coolant when I stopped. However, the night the light came back on, I was on my way home and left it in the driveway. When I went back out the next day, I cranked it, light came on, I went to the store. When leaving the store, I decided to take it to the dealer. But when I cranked it, no light. This went on for another week. The light came back on after a week and i then took it to the dealer. They stated I needed a new battery. I took it to another store and had them replace with a new battery. However, I still have the same check engine light come on, stay on for a day or so and then goes off. It has progressed to intermittently coming on while I am driving. But if I crank the jeep on and off a few times, the light will go off and doesn't seem to affect the driving. Also, my code reader doesn't read any codes with the light on. Today, it sputtered when I tried to crank it on 2 attempts. On the third attempt, I applied the peddle and it cranked up. When I got home I shut it off, and cranked it again twice without a problem. This is my first jeep and I am Jeep ignorant. Any ideas.....

That is a coolant temp sensor code. Everything your dealer had done to try to “fix” it has nearly nothing to do with that. Unless you’re mistaken and it was a P0128 code, but that wouldn’t cause fan to run high or hard starts.

Your coolant temperature sensor is on the fritz which will cause all your issues. It could have coolant seeping through it also. Check it. It’s behind the drivers side head if I recall correctly.

Seeing a dealer throw a thermostat and batteries at that particular issue infuriates me honestly. It’s not that complicated and hard to believe they couldn’t figure this one out.

 

[Blacksport]

Get a Mishimoto 185° thermostat and a new temp sender. If you want to totally say goodbye to high coolant temps, add the RPM Extreme fan controller.

 

[Lifeisgood72]

That is a coolant temp sensor code. Everything your dealer had done to try to “fix” it has nearly nothing to do with that. Unless you’re mistaken and it was a P0128 code, but that wouldn’t cause fan to run high or hard starts.

Your coolant temperature sensor is on the fritz which will cause all your issues. It could have coolant seeping through it also. Check it. It’s behind the drivers side head if I recall correctly.

Seeing a dealer throw a thermostat and batteries at that particular issue infuriates me honestly. It’s not that complicated and hard to believe they couldn’t figure this one out.

Thanks, Going to look at that. I ;m posting a few pics here of the check engine light on and the temp control hasn't budged on the dash. This is me driving after about 15-30minutes.

 

[bmpcamry09]

Thanks, Going to look at that. I ;m posting a few pics here of the check engine light on and the temp control hasn't budged on the dash. This is me driving after about 15-30minutes.

Yeah. You need a sensor or have wiring issue to the sensor. But high codes like that are almost always the sensor. Even if your thermostat was stuck wide open you’d have more coolant temp than that.

 

[Wabujitsu]

The fact that your analog temp gauge remained at dead-cold after operating the vehicle clearly indicates a failed temp sensor and/or wiring, as the previous poster said. That temp gauge should have been a third to halfway up to H.

How is your coolant level? I am concerned that you have also smelled coolant, which indicates a leak and/or an overheated state.

 

[Lifeisgood72]

Thank you all for your feedback. I bought and replaced my thermostat housing (included temp sensor). I ran the Jeep for 2 days without any problems. Then, on my way home from work, temp gauge dropped to zero and engine light came on. Code P 0118. I might include here that my temp gauge has NEVER gotten above half way up. I double checked my fluid levels and all is well, no new coolant smells. Was told this could be related to small air bubbles caught in the system. Was told to park at an incline and remove the coolant cap and go through the process of 'burping' again. I'll do that and check my wiring the next few days. Any other suggestions?

 

[Wabujitsu]

Typically you will get wild swings in your temperature readings, due to bubbles of air passing by the sensors. It will go very cool to very hot. It typically won’t stay in the cool range for very long at all.

A large air pocket can cause an overheated condition as well. You can try the burping method. I chose to spend around $60 USD to get a vacuum kit, to pull vacuum on the cooling system and fill it under a vacuum. You will need to have at least a small shop compressor on-hand. Here is the kit I bought; it works great! https://www.amazon.com/dp/B0F434CFMT?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1&th=1

 

[mgroeger]

The fact that your analog temp gauge remained at dead-cold after operating the vehicle clearly indicates a failed temp sensor and/or wiring, as the previous poster said. That temp gauge should have been a third to halfway up to H.

How is your coolant level? I am concerned that you have also smelled coolant, which indicates a leak and/or an overheated state.

Smell does not always equate to leak. I have a 2021 Alfa Romeo which has the same engine as my 2021 Wrangler. I had to have the water pump replaced which means the cooling system needed to burp until all air was removed. I was told this was done and I was good to go.
Fast forward to a drive across country and my coolant dropped a little and I was smelling it. Took it to a different shop and they used a pressurizer to test for leaks, which none appeared, and then a vacuum and were able to get a little bit of air out. He said if there is any air in the system and it is trying to burp out you will actually get a smell as it seeps out. I didn't quite understand that but it turns out he was right. Coolant is perfect now and there is no smell.

 

[Wabujitsu]

Smell does not always equate to leak. I have a 2021 Alfa Romeo which has the same engine as my 2021 Wrangler. I had to have the water pump replaced which means the cooling system needed to burp until all air was removed. I was told this was done and I was good to go.
Fast forward to a drive across country and my coolant dropped a little and I was smelling it. Took it to a different shop and they used a pressurizer to test for leaks, which none appeared, and then a vacuum and were able to get a little bit of air out. He said if there is any air in the system and it is trying to burp out you will actually get a smell as it seeps out. I didn't quite understand that but it turns out he was right. Coolant is perfect now and there is no smell.

Thank you for that, Mike! Makes perfect sense.

 

[Lifeisgood72]

The fact that your analog temp gauge remained at dead-cold after operating the vehicle clearly indicates a failed temp sensor and/or wiring, as the previous poster said. That temp gauge should have been a third to halfway up to H.

How is your coolant level? I am concerned that you have also smelled coolant, which indicates a leak and/or an overheated state.

Coolant level has been normal. After replacing my thermostat, no more coolant smell. However, I made a notation to the feed about my light. I think I'm going to have to check the wiring.

 

[Lifeisgood72]

Smell does not always equate to leak. I have a 2021 Alfa Romeo which has the same engine as my 2021 Wrangler. I had to have the water pump replaced which means the cooling system needed to burp until all air was removed. I was told this was done and I was good to go.
Fast forward to a drive across country and my coolant dropped a little and I was smelling it. Took it to a different shop and they used a pressurizer to test for leaks, which none appeared, and then a vacuum and were able to get a little bit of air out. He said if there is any air in the system and it is trying to burp out you will actually get a smell as it seeps out. I didn't quite understand that but it turns out he was right. Coolant is perfect now and there is no smell.

So, this makes sense as to why I get the intermittent check engine light, yet the engine appears to run fine. I may have a local garage pressure the system. Or I may buy the tools and do it myself since I have been told thermostats have a short life in the 3.6.

 

[mgroeger]

So, this makes sense as to why I get the intermittent check engine light, yet the engine appears to run fine. I may have a local garage pressure the system. Or I may buy the tools and do it myself since I have been told thermostats have a short life in the 3.6.

Yeah if you have air in the system and it hits the sensor it will give a false reading and I could see that throwing the engine light.

 

[mwilk012]

You 100% have a wiring problem, most likely AT the connector itself. It’s been manhandled too many times for it to not suffer some wear.

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