2015 Yukon XL temp gauge at 0 and radiator fan running constantly

[Stealthee]

If the fan running for 15 minutes killed your battery multiple times, then it was already on its way out.

[Mendoza33]

Any updates on this?? Our truck is doing the EXACT same thing. We've replaced the sensor 2 times already. It'll work intermittently.

[Stealthee]

Quit buying junk sensors. If you read the thread the last post about the sensor said it was good to go.

[ProMark Auto]

I Got this issue with 2015 GMC yukon, the first sensor i got is autozone brand which failed after one month, second one i bought from GMC dealer which failed after 3 days, i am suspecting it could be a faulty ECM, i am doing the scope test tomorrow to confirm if its ECM or the wires.

[DeanO2022]

I am very interested in following this. I have a 2015 Yukon XL and have replaced the TCS three times.

It is intermittent. Will run for a few weeks and then the temp goes to 0 and fan runs. Then it will go another week. Seems like it happens more when driving on surface streets.

Can the wiring harness be replaced without removing an entire harness? Where can I check the resistance up the line further.

Someone mentioned the ECM, where is that at? Just real frustrated I can't fix this!

[Cafe Y Tabaco]

I have had this same issue with the fan running and the gauge showing 0 temp. The dealer said it was the thermostat getting stuck open which was completely wrong. I found that this happens when the voltage is a bit low. If I take it on the fwy and step on it the V goes up and the temp indicator turns on and the fan shuts off
Still don't know why I'm having the V issues.

[Blue Bowtie]

As with many vehicles of this lineage, it's usually informative to check the reference voltages to sensors in the PCM harnesses underhood, as well as grounding. A 2015 model may not be old enough, but many older vehicles can develop issues with the connectors at the PCM itself, and disconnection/inspection/reconnection can resolve some of those problems.

[Theguitarzombie]

As of now, this universal problem is unresolved.

I have this problem too, but I can’t replace the sensor myself. Once, the problem went away, then came back on its own. I paid $140 to get the sensor replaced, lasted about 3 months. These type of sensors are not intermittent. If you look at this problem in its entirety (read comments), there is no real data to digest this problem. So, I will start. I will again replace the sensor and get the “failed” one from the repair shop. Then I will test the resistance. I will record the effort. Some say they used OEM sensors and still have this problem. So it seems NOT to be a cheap sensor issue. There are other possibilities, perhaps unlikely, but car manufacturers have been caught doing hijinx, such as peppering emissions data (VW and others). Perhaps GM has purposely caused this problem. A voltage spike might kill a sensor. I am not saying this happened, but with a problem like this, thinking outside the box might resolve this. Learn how to measure resistance.you can get. Voltmeter from harbor freight for $7.99.

I will start by disconnecting the battery, clearing codes and observations. Then, replace sensor, correctly check resistance. If the resistance is off, then is the sensor cheap or is there a voltage spike killing it. I do not have a voltage logger, to monitor the voltage. I wish I did.

The large number that have this problem, bad sensors, loose connectors, bad computer, with all you experts, you would think this one would be easy. If you still believe it is cheap sensors, then it should be easy to prove (intermittent cheap sensors? I doubt it). Let’s gather some data to make the solution more definitive (says the new member).

[Blue Bowtie]

The only potential "planned obsolescence" may be from the wire harnesses used in vehicles. The massive push to lighten vehicles, provide excessive automation and monitoring, be "environmentally conscious", and reduce build costs could have resulted in less robust wiring. It may not happen as frequently in Georgia, but in the Rust Belt of the midwest I've seen multiple examples of wiring failures, often with crimped connections, and all resulting from oxidation, overload, and corrosion. 18 gauge wire fused at 10A or more, no solder on bussing and interconnections in fuse panels and UECs, and literally dozens of wires bundled into looms which are intended to flex and move with the engine and suspension.

What could possibly go wrong after the warranty expires?

[Stealthee]

There reason there is a "large number" is because there are a metric shot ton of these vehicles on the road. Also forums are where people come to post about when they have problems. No one posts a thread when their vehicle is running good.

[Theguitarzombie]

Well, despite my long winded rant this morning, I got in my 2015 Yukon Denali XS and as expected the fan was blaring at cold temp (just started from overnight). I drove about 3 miles, no engine temp. After being in the store for 20 minutes and coming home, I noticed engine temp was reading but check engine light on. By the time I got home - 2 more miles, the check engine light is off. Oh well, my science project will have to wait until next time.

On an earlier Yukon model, my brake switch was faulty (also a universal problem) and I replaced it. I looked at the failed one carefully and could not see the problem with it, despite being a mech engineer with over 30 patents. Sometimes small imperceivable things can contribute. I suspect wiring for the eng temp problem too. It is VERY unlikely that cheap sensors will come and go, besides many reported using OEM switches with the same bad results. The clue here people is intermittent.

[jofarmer]

I have been dealing with same problem on a 2017 Denali. Replaced sensor with acDelco only to have same problem a week later. I checked resistance on both sensors and they read the same. Checked wiring and connector and they all seem fine. Anybody have any luck or an update on what fixed this problem on their vehicle?

[travesty69]

Here is my experience with same symptoms. I replaced the sensor and the connector. It worked for a couple days and then went back to low temp reading and high fans. I have disconnected the battery long enough for the computer to reset, and it goes back to working again immediately. I have done this several times now, and it always starts working immediately. One time it kept working through a 600 mile road trip. Another time, it only worked for 20 miles. I'm only 3 weeks since replacing the sensor, so not sure how many times I will have to keep resetting the computer.

[Theguitarzombie]

It has been a few weeks since I posted my response, reporting my intermittent low temperature reading causing the fan to run (protection mode) in my 2015 Yukon Denali. It went away for a while and recently came back. This thread has not convinced me that anyone has figured this out. I refuse to replace the sensor with a aftermarket or OEM sensor. In my experience, it is very unlikely that sensors are intermittent. Couple that with the reports here, where the exact problem occurs with “cheap” sensors and OEM sensors and repeats soon after replacement. Logic should tell you that the problem is not the sensor, a) if it is intermittent and b) problem still occurs with “cheap” OR OEM sensors.

For me, the most logical would be a bad connection or a voltage spike. How do we resolve this? The only way I would go is to monitor the voltage realtime (as has been previously mentioned). I will look into how to do this cost effectively.

Meanwhile, are there any detriments (besides battery usage) to running in protect mode?

[Blue Bowtie]

Don't be too surprised that if you ever get to the resolution of the problem, you may find several failed or failing wires in a harness. That's nothing new around here.




Look closely, and the other wires which are in the process of failing become apparent. You won't find this with a scanner, nor a meter. It requires functioning neurons, which is why dealerships' service departments throw in the towel and tow vehicles off to specialists.