Engine And Engine Cooling Problems of Cadillac XT5 - part 1

While driving at highway speeds, I needed to accelerate hard in order to pass another vehicle and while accelerating there was a downshift and increase in rpm. After passing, the rpm remained high even after I took foot off accelerator and it seemed the transmission did not shift back out of lower gear, keeping the car traveling at a high rate of speed, endangering myself and other traffic. Applying the brakes would not cause the engine to slow down and the engine kept working hard and traveling fast, causing strain on the brakes to slow down. I pulled over and initially shifted to neutral, but the engine was still revving high (4000 rpm observed). Then I placed the car in park which did not change the high rpm. Then I shut off engine and let it rest. Then I turned auto back on and all was normal. The problem has not yet been reported to dealer but will occur in coming days. There were no prior symptoms, problems, or warning lights on dash display prior to this occurring.

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To whom it may concern,I am writing to formally report a safety concern involving my 2018 Cadillac Xt5, VIN [xxx] . Recently, my vehicle displayed a “steering assist reduced” message on the dashboard while driving. This warning significantly increases the physical effort required to steer the vehicle, especially at low speeds, and I believe it presents a genuine safety hazard. Upon taking the vehicle to an authorized Cadillac dealership, I was informed that the vehicle had stored diagnostic trouble code p0128 (engine coolant temperature below thermostat regulating temperature). The dealer explained that a malfunctioning thermostat caused the steering assist reduction message to appear. However, at no point did the vehicle illuminate a check engine light, despite the presence of an emissions?related fault code. I am concerned for several reasons:a critical engine fault (p0128) did not trigger a check engine light, leaving me unaware of any underlying issue. The vehicle reduced power steering assist as a result of an unrelated thermostat malfunction, creating a sudden and unexpected increase in steering effort. This behavior poses a safety risk, particularly in situations requiring quick steering response or low?speed maneuvering. Cadillac has issued service bulletin 17na158, which acknowledges that thermostat or coolant?temperature?related issues can trigger steering assist warnings. This suggests the manufacturer is aware of the problem, yet no recall or corrective action has been issued. Given that steering assist reduction directly affects vehicle control, I believe this issue warrants investigation. A driver should not lose steering assist because of a thermostat fault, nor should a vehicle fail to illuminate a check engine light when a diagnostic code is present. I respectfully request that NHTSA review this matter to determine whether a safety?related defect exists in the 2018 Cadillac Xt5 and similar gm vehicles. Sumitting this for my mother. Information redacted pursuant to the freedom of information act (foi.

The contact owns a 2024 Cadillac Xt5. The contact stated that while driving approximately 10 - 15 mph and depressing the accelerator pedal, the vehicle failed to respond. There was an abnormal vibrating sound coming from the engine. A dealer was contacted. The vehicle was taken to the dealer, where it was diagnosed, and determined that the transmission needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure, and informed the contact to return the vehicle to the dealer for more diagnostic testing, and a case was opened. The failure mileage was 23,000.

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The contact owns a 2018 Cadillac Xt5. The contact stated that while driving at an undisclosed speed, the vehicle inadvertently lost motive power. The contact was able to coast to the shoulder of the roadway, where the vehicle failed to restart. While attempting to restart the vehicle, the vehicle required several attempts before restarting. After the vehicle was restarted, the vehicle returned to normal functionality, but the failure became a regular occurrence, prompting the contact to discontinue driving the vehicle. No warning lights were illuminated. The vehicle was taken to an independent mechanic, who was unable to determine the cause of the failure. The vehicle was not repaired. The manufacturer was notified of the failure but provided no assistance. The contact was advised to take the vehicle to the dealer for assistance. The failure mileage was 40,000.

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.

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When braking — both at low speeds and when slowing from highway speeds (40+ mph) — vehicle feels like engine revs and is still pushing against the brakes. Requires very firm pedal pressure to hold car in place; if brake pressure is eased, vehicle surges forward until it finally settles after several seconds. Concern is intermittent but repeatable. I had a near collision on 10/3/2025 due to this issue. I have been in constant contact with the dealership on this, including the service manager, as well as Cadillac care. The dealership has test driven the vehicle several times and has been unable to replicate the problem. However, I do have an audio recording of the engine’s idle speed at various points during one incident.

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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.

The contact owns a 2018 Cadillac Xt5. The contact stated that while driving at an undisclosed speed, the vehicle stalled with the check engine warning light illuminated. The vehicle was towed to the dealer where it was diagnosed that the engine had failed and needed to be replaced. The vehicle was not repaired. The manufacturer was not made aware of the failure. The approximate failure mileage was 86,000.

The contact owns a 2019 Cadillac Xt5. The contact stated that while driving on the highway at 25 mph, the vehicle lost motive power. There were no warning lights illuminated. The contact was able to coast the vehicle to a stop and park on the side of the highway. The contact waited for a while before restarting the vehicle. The contact continued to drive the vehicle; however, the failure reoccurred. The local dealer was contacted; however, the vehicle was not diagnosed or repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 95,800.

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Faulty termostat which creates reduce steering error code po128, tempeture indicator is not listed on the dash board, engine rpms are increased. This problem has increased for now the engine check light is highlighted.

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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.

Driving vehicle when it lost all power and stopped. On a main road . No lights, no start. No emergency flashers ! vehicle had to be towed to dealer ! vehicle was stuck on main road in traffic. And could not be moved because since it had no power at all was stuck in park!.

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Purchased 2024 Xt5 brand new less than 6,000 miles ses light on. . Dealer states part failure w/transmission snap ring-traded vehicle for 2025 Xt5. At 5,464 miles ses light comes on-another internal transmission part failure this time control valve body needed to be replaced. The control valve body is currently being recalled in the Cadillac ct5 but gm has not acknowledged issues with the control valve body on the Xt5. After leaving the dealership after being serviced for a control valve body replacement I was involved in an accident 79 miles later/none of the safety features on this $60,000 vehicle engaged… no emergency braking… no vibration of seat…. No audible or visual alert stating approaching the vehicle to closely-nothing!.

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I received a steering assist is reduced message and the cooling fan ramped up to full speed. In contacting Cadillac, it seems that it is a below temperature error for the thermostat. Unsure what the thermostat has to do with steering. Also in researching this, this is a wide spread issue and needs to be a recall. My Xt5 has 48000 miles on it and the powertrain warranty expired 3 months ago. I believe this should be a recall and should be repaired by the manufacture as it could cause a safety issue while driving.

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).

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.

The coolant thermostat was broken and gave two check engine codes p0128 and p0128p. Ac was not functioning when the thermostat was not working, which can be dangerous in summer. It is also a very common problem with Cadillac Xt5 and GMC acadia.

Engine & transmission. Do not know if my safety is at risk. Yes, the problem has been duplicated and confirmed by my Cadillac dealer. Vehicle vibrates when engine switches from 6 cylinders to 4 cylinders. The vehicle has been inspected by the dealer. Odi # 11610835.

Engine problem loss of power intermittently no reverse. They replaced clutch parts seals, piston, rings, plates, and plates. Had vehicle for about 22 days. Driving home after repairs completed. Cluster display- instrument panel went out. Called dealer and Cadillac assistance. Says there nothing they can do until Cadillac releases a fix. I believe vehicle is a safety risk for the second time with no remedy for instrument panel not functioning. Thank you greg.

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!.

Was driving the other day and the message steering assist reduced, ac fan was blowing but no a/c then engine light came on. Made appointment next day with my Cadillac local dealer and service writer said he knew what the problem was. After he plugged into my car, then into his computer it read - bad thermostat. Fortunately, mine was covered under the powertrain warranty, however, he said there were 4 other vehicles just like mine (xt5) in there for the same issue. This is a well known issue with Cadillac and for those of us who have a warranty that's good. Otherwise, it is $1,200 to fix!!! ouch!! not sure why Cadillac hasn't issued a recall on this problem and very disappointed in them for not doing so.

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.

I was driving on the freeway, came to a stop as traffic increased, then the car shut off m. I had no power, could not get out of the vehicle, no hazards, no tail lights, nothing. I had a complete panic attack, I thought I was going to die. I called onstar from my cell, they could even locate me. After 30 mins, calling 911, texting the representative from the dealership in which I purchased the car, it turned back on. Either the car was shut off with a signal or there is a serious hazardous issue that needs to be addressed.

While traveling home to louisiana from a vacation, I noticed the engine temperature what stuck on cold. We also were experiencing loss of power steering, and loss of ac in the car. We stopped at autozone in destin, FL where they completed their fixfinder which reported the thermostat needed to be replaced, being it was stuck in the open position and wasn't properly gauging the engine temperature. Some of the engine fluids were extremely low due to overcompensation because of the thermometer issue. Seeing as we were traveling and not near our local mechanic or dealership, we called around to various auto shops to see who could fit us in same day. The only available shop, without having to spend an additional night in FL, was pep boys in fort walton, FL. They also let us know they did not have the thermostat compatible with my engine in stock, so that would need to be purchased at autozone if we wanted the car fixed same day; which is what I did. While we were at pep boys, there was another Cadillac Xt5 there for repairs to their ac. It turned out, they were having the exact same issue I was having, but it hadn't escalated to the power steering yet. The mechanic googled the two issues and found there are known issues with the engine thermostat in this make/model, but there has never been a recall issued for it. Now Cadillac is refusing to reimburse me for the repairs because I was still within my powertrain warranty (under 73k miles) but because we were in a hurry to get home from vacation to get back to work, we did not take the car to a GMC dealership, so the powertrain warranty is apparently useless here. My extended warranty is also useless because the powertrain warranty is still in effect.

When driving the car on Jul 20, the check engine light came on. It went off upon arriving home. We had it checked at our local napa auto care and they did an electronic engine control test. The garage did not clear trouble codes and advised us to take the car to a dealer. Upon driving the car on Jul 30, the check engine light came on once again. In may 2020, when we had our car in for service, at sutliff, in state college, PA, they took care of the engine control, software issue. This dealer is no longer open so we started taking our car to blaise alexander in altoona, PA we, also, have had several incidents with the parking brake not releasing. We took the car to blaise alexander, in altoona, on 3-14-23, and they said that the software showed no problem with the parking brake. They advised me to call a tow truck and have it towed into their garage the next time it happened. There is a Cadillac dealer in ebensburg, PA which is approx 30 miles away. We are in a dilemma as to have it towed there or have it towed to the gm dealer in altoona, PA which is approx 16 miles away. Our car has 50, 813 miles on it. I will have it towed either to the Cadillac dealer or the gm dealer.

At a red light in traffic, it suddenly shut off the engine, emergency brakes went on, multiple warning lights were on (low bat, low fuel {full of fuel}, lower passenger window, etc. . ), totally immobilized itself by not being able to start the car or push it with the brakes on! 81 year old female driving and if the car did this at highway speed it could have been a catastrophe! it appeared everything else in the car was working but had 'self immobilized'!.

This vehicles transmission has went out twice. Both while driving and could have caused death on the freeway because the vehicle came to a complete stop. 2 young children could be at high risk for this issue. It was taken to the dealership the first time and the transmission was replaced and within 3 months the same issue occurred which could have been deadly. It again was given a new transmission and 6 months later the same issue is occurring. Yesterday the check engine light came on. The vehicle began to drive very slow as I was on the main road. Another collision could have occurred but thankfully I was able to turn into a parking lot and stop the vehicle. Gm corporate has been contacted multiple times and have stopped answering all my calls and conerns. This issue can cause major damage to my family as well as others. A new vehicle like this should not have these issues.

The contact owns a 2023 Cadillac Xt5. The contact stated that on two occasions while driving at approximately 25 mph, the steering wheel seized, and the vehicle veered to the side of the road. Additionally, the gear shifter malfunctioned and the light to indicate that the vehicle was parked, was inoperable. The abs, check engine, powertrain malfunction, and brake warning lights were illuminated. The vehicle was towed to a dealer where it was diagnosed and determined that unknown part needed to be replaced. The manufacturer was notified of the failure. The failure mileage was approximately 1,000.

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.

The contact owns a 2017 Cadillac Xt5. The contact stated that while driving approximately 40 mph the vehicle over heated and stalled. The power steering assist was reduced and drive with care messages were displayed. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The vehicle was taken to an independent mechanic who informed about the thermostat, engine, and code p0128. The manufacturer was not contacted. The approximate failure mileage 43,806.

Driving down the road and my 2018 Cadillac Xt5 started on fire for no reason and no engine lights came on. I loss all driving control power steering in the matter of seconds and was trapped in the car waiting for cars to clear so I can run out. The car is with my insurance company the car is now a total loss and I don't think they will investigate. I called gm to make a complaint. The fireman said he had just put a fire out on the same car a week ago. I found out that we have 2 more cars in the macomb county mi area that caught on fire in the last 3 months same type of car.

Engine thermostat defective, which causes the computer to speed up radiator fans, and causes temperature gauge to read zero. Dealer replaced under warranty at 68,000 miles and same problem reoccurred at 90,000 miles. Common problem on Cadillac Xt5’s (all years).

Engine light comes on, brake assist service light comes on when transmission idles down at stop signs, stabilitrak service light comes on after transmission idles down after a stop. This has happened twice and I had to get it repaired.

The contact owns a 2018 Cadillac Xt5. The contact stated that after coming to a complete stop, the vehicle lost motive power. After restarting the vehicle, the vehicle would operate as needed. The failure occurred on multiple occasions. The cause of the failure was not yet determined. The local dealer and manufacturer were not yet notified of the failure. The failure mileage was 40,000.

Xt5 bumper-to-bumper warranty expired on 6-1-21. Both key fobs suddenly quit working on 7-17-21. Took to dealer 7-21-21. Cost me $300. Got it back on 7-26-21. Drove vehicle for the first time after getting it back on 7-28-21. Key fob quit working again briefly then started after I kept trying for a few minutes. After driving for 5 miles, the car completely died on very busy road - no steering, no dash lights, break lights - then the car suddenly braked really hard and I almost got rear-ended. 4-way flashers wouldn't work so I had no way to warn other drivers coming up behind me. I also was a sitting duck as I couldn't exit the vehicle since the doors wouldn't unlock and windows wouldn't go down. The temperature was in the 80s and I quickly began to overheat. I tried to signal other drivers who were beeping their horns and swerving around me until several pulled over to help. After approx. 10-15 minutes, as I was calling 911, the doors unlocked and I got the 4-ways to come on though they were working erratically. I called the dealership and they came and picked up the car. They've had it for a week and don't know what's wrong with it. This is a potentially deadly safety issue; I could have died or caused someone else to be injured or die due to the car suddenly losing all power while driving in heavy traffic with no warning, then braking hard and very unexpectedly, along with the inability to warn other drivers due to the inoperable 4-ways I also could have succumbed to hyperthermia as there was no way to escape from an extremely hot car. It appears that after doing some basic research, that this is not an isolated problem with the 2013-2017 Xt5s. There are numerous reports of incidents similar or identical to mine found on various Cadillac owners online forums. Additionally, a common complaint is that this problem has not yet been solved yet by general motors and their dealerships are at a loss to resolve this issue (they haven't been able to fix mine yet!).