My 2020 Silverado HD truck requires a replacement wiring harness and DEF tank and is basically inoperable. This is a known issue for GM and spans multiple model years.GM continued to produce throughout multiple model years knowing that owners may be stranded and unable to use these vehicles because of the defective parts. Hardships for owners would include loss of income and exposure to various dangerous conditions. The DEF tank has a heater system that can get exposed to the DEF fluid because of a poor design and poor manufacturing standards resulting in short circuit. GM will replace the wiring harness and combination tank/heater assembly under warranty. The parts are supposedly on NATIONAL BACK ORDER, yet GM continues to manufacture and ship new 2022 models with the required parts needed for repairs. GM will not provide alternate transportation. Supposedly in excess of ten thousand trucks are affected. Warm climate owners and warm temperatures may affect this issue positively. GM has no policy for a timely response to this issue. Trucks will become unsafe to operate when the electronic controls limit the truck speed to 5 mph or less. An operator may become stranded and exposed to dangerous highway conditions if stranded with this issue.

- Fenelton, PA, USA

The DEF heater/tank shorted out. The DEF system has thrown a code 3 times in the little over a year I-€™ve owned the truck. This final time I was told that the tank needs to be replaced. The truck has now been in the shop for 2 months and there is still no ship date on the replacement tank. The tanks are on a national back order. From what I understand there are about 9,000 people waiting for this DEF tank countrywide. I now have a $60k work truck that I am paying for but cannot use with no reasonable end in sight.

- Scituate, MA, USA

Service DEF message in truck that will soon result in reduced speed. Local and purchasing dealers both stated a new DEF tank is needed. A tank is not available and is on back order.

- Homer Glen, IL, USA

DEF tank heater short causes wiring harness to melt and fault on diesel trucks, enabling limp mode. Limp mode is dangerous when hauling trailers over long distances. Faulty part is on 6 month backorder. No reparations from GM.

- Massillon, OH, USA

My vehicle is less than 1 year old with about 11500 miles. My service exaust system warning light illuminated and provided a warning that my speed would be reduced in a set amount of miles. After adding additional def fluid to determine if that was the issue my car the car returned an error of service def system. This then lowered the amount of driving mileage until my car would be forced to a reduced speed. This occurred while operating the vehicle and may have resulted in damage to my vehicle or other motorist when traveling on an expressway. The dealer explained that they had other cars in for the same issue and it took over a month to get the parts in for repair. Additionally GM has provided no guidance or warning regarding the issue.

- St John, IN, USA

Vehicle is a diesel has about 13,000 miles on it only. Received a warning on the dash while vehicle was in motion that the def system has an issue and to see the owner manual. Says about 80 miles until max speed will only be 65 mph. Took to dealer and stated that it is the def pump in the tank. The part is almost impossible to get right now because it has been faulty on so many of these vehicles and has needed replacement. Have to leave vehicle at dealership until they can get a part in otherwise vehicle cannot be driven.

- Bismarck, ND, USA

Three days after purchasing my 2020 Chevy 2500 Silverado, on September 28th, 2020 around 1253 I tried to start my truck and it wouldn't start. The truck turned over but seemed like it wasn't getting fuel. I then received a diagnostic alert. After changing the relay the truck ran fine. I then scheduled to take it in to the dealer on October 5,2020 to have a diagnostic done on the truck and they found nothing. The very next day it did the same thing on October 6th, 2020. I then scheduled to have it taken in again and found out that the fuel control module on several other GM vehicles where faulty on new vehicles. I had to cancel my second appointment due to the dealer wouldn't provide me with a loaner car while they worked on my truck. This vehicle is under warranty. Then again on the October 20th, 2020 the vehicle would not start. After changing out the relay switch it seemed to reset the system and starts and runs fine and the check engine light goes off. I work in emergency services and need my truck to run when I turn the key over. There's no common factor leading to this lack of turning over. And my dealer is not working with me to come to a solution to this problem. This has happened on 3 occasions at random times.

- Virginia City, NV, USA