The thermostat quit working. I've researched this issue and have seen this is a very common issue usually occurring when the vehicle has somewhere between 45000 to 55000 miles.
2017 Cadillac XT5 engine problems
24 complaints (19% of all complaints for this car). Typical mileage when it fails: 16,000.
- owner complaints
- 24
- of this car's complaints
- 19%
- typical mileage
- 16,000
- crashes
- 0
- recalls
- 0
Which part fails
Owners did not name a specific part.
At what mileage
Complaints by mileage at the time of the problem.
0k-25k
25k-50k
50k-75k
75k-100k
100k-125k
125k-150k
150k-175k
175k-200k
200k+
Cadillac XT5 engine problems in other years
Specific symptoms reported on the 2017 Cadillac XT5 engine
Phrases found in the owners' own descriptions, so one complaint can mention several symptoms.
Related recalls
No recalls on record for this model year.
What 2017 Cadillac XT5 owners say
Most recent owner complaints, unedited.
I had P0128 Code with a warning message " Steering assist is reduced, drive with care". My local mechanic told I need a new thermostat. I have replaced my thermostat and it cost me 700 dollars out of pocket.
Catalytic Converter on my 2017 XT5 had weld crack Oct 2025. Causing loud noise and exhaust to enter cabin of vehicle. This was the second convertor to do this. In 2023 I had to have the other catalytic convertor on this same vehicle changed out by the Sewell Cadillac dealership for the same problem. That time I only had 50,000 miles on the car so the dealership did it for free (after I found that they had to cover up to 80,000 and they acted like they didn't know that and had quoted me $2000). This time in 2025 I had 80,805 miles so I had to pay $1010 to have it replaced by an outside repair shop. The technician says since we had to have them both replaced and the car is only 8 years old, it is probably a design flaw. He told me to report it. I see another complaint for the same thing and I see they did a recall on some from California vehicles for something with the catalytic convertor and a recall on some in 2022 and 2023 vehicles for an issue with the catalytic convertor. I expected better from GM and Cadillac. I wonder how many other Cadillac XT5 owners have had this problem but haven't known to report it. You should contact the Cadillac dealerships and see how many they have changed out.
An issue is pipe cracking at the left catalytic converter mounting flange weld, causing exhaust noise, odor, and potential emission system failure. It just cost $2013.00 to have fixed.
While driving my vehicle, alert popped up on my dash stating "Steering Assist is Reduced Drive with Care" futhermore after that my Check Engine Light Turned on and my Engine Heater Stayed cold and would not warm up. Vehicle has been inspected by the Cadillac Dealer and they stated it is all due to the Sensor. However Sensor is on backorder and has taken them 3 week to get the part. They stated it is safe to drive even though all those alerts came up, since he said it appears to be stuck open, however they stated if it gets stuck in a closed state then the engine could overhead which would require having the vehicle towed in. They offer a "limited" warranty on this however since I just was past the warranty period they state you have to pay the full price. Warranty is for 85,000 miles and I am barely above it at 87675.
This model Cadillac XT5 has early failures of engine cooling systems thermostats. The thermostat sticks open causing lower engine temperatures and higher emissions. The first sign you have an issue is a reduced power steering assist message on the instrument display. The engine control module stores a p0128 code as current. Continue driving the vehicle the ECM will shut off AC compressor engagement, so no AC. The next thing that happens is you lose temperature gauge. So you are now driving vehicle with reduced power steering assist, no AC and no way of knowing if the engine is overheating. This is a known issue with the refer to GM bulletin # 17-NA-158 posted May 2017. There has been a such a demand for this thermostat, that parts back orders are common. The volume of failures should be addressed as a recall including refunds to owners who have had to pay for this repair. The fact that a colder running engine typically runs richer based on ECM programming, causes higher emissions. GM hasn’t been helping people with this repair for out of warranty vehicles. Our 2017 XT5 failed at 38,000 miles. Cadillac only offered to pay 30% of the repair leaving a balance of $585.00! This was all because GM’s failed part.
Our XT5 began getting 'Steering Assist Reduced' message about a year ago. It comes and goes , coming more often now. The problem is the thermostat and is a very common issue with numerous complaints here and on Cadillac forums (below). The problem is, when this issue occurs the AC stops working, and when that happens you have no windshield defrost, and that is a safety problem. Cadillac has TSB's describing this issue but refuses to cover it goodwill as we are slightly out of warranty. The repair is extensive, requiring 4.5 of time. [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
The thermostat has malfunctioned twice in 2 years. Driving vehicle and dash warning" STEERING ASSIST IS REDUCED DRIVE WITH CARE", also the temperature gauge was showing COLD and this was after driving for over 30 minutes. Contacted local dealer and was informed this is a KNOWN problem with the thermostat sticking open. My brakes are sticking often and my car often jumps hard when i put it in reverse.
ECM- engine system. Diagnostic code P26C8. Chassis Control Module Requested Malfunction Indicator Lamp Illumination. The DTC is an informational DTC. The DTC indicates an emission related DTC set in the Chassis Control Module. My service transmission message came on and would not let me go into reverse or drive. The next day the check engine light was on. This vehicle is only 34,650 miles and is a 2017. I bought it on Saturday and this happened on Wednesday!
The thermostat is malfunctioning. Vehicle has less than 50,000 miles. Driving vehicle and dash warning" STEERING ASSIST IS REDUCED DRIVE WITH CARE", also the temperature gauge was showing COLD and this was after driving for over 30 minutes. Contacted local dealer and was informed this is a KNOWN problem with the thermostat sticking open. If this had been in the summer the A/C would not have worked. I was informed I could bring in the vehicle to have the codes cleared and the parts would have to be ordered. Due to backlog of parts, it was unknown when the parts would be available. In searching internet there are a significant number of owners who have experienced the same issue. In consulting the mechanic, I use, I was informed this is an issue with the motor in my vehicle. The same motor is in other GMC products, and he has 3 vehicles in his shop with the same issue waiting parts.
Questions about the 2017 Cadillac XT5 engine
Does the 2017 Cadillac XT5 have engine problems?
Owners have filed 24 complaints about the engine of the 2017 Cadillac XT5, 19% of all its complaints.
At what mileage do 2017 Cadillac XT5 engine problems start?
The typical (median) mileage in owner complaints is 16,000 miles.
Was there a recall on the 2017 Cadillac XT5 engine?
There is no recall for this problem on this model year.
What year does the Cadillac XT5 have bad engine?
The Cadillac XT5 model years with the most engine complaints are 2017 (24 complaints) and 2018 (15 complaints).
Other 2017 Cadillac XT5 problems
Transmission 26Electrical 21Brakes 17Steering 15Acceleration 9Driver assistance 9Wheels 8Visibility 6Lights 5Suspension 5Airbags 4Fuel system 3Seats 3Body 2Seat belts 2Tires 1
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