2021 Chevrolet Silverado 1500 Electrical Problems

May 28 ,2026 I left work to get some lunch And when I went back inside my vehicle I turned it on and the check engine light came On and on the dash it was telling me to park the truck and it wasn’t going more then 45mph so I called my dealer ship simspson Chevrolet in garden grove and they told me they couldn’t do anything because it wasn’t under warranty so I had to take my truck to a near by auto shop because my truck is my daily and I use to get to work so the. The body shop found out the problem it was the wiring harness it was the way they installed the wiring harness it’s manufacturing I called my insurance company and I called GMC directly and they don’t want to help me

NHTSA ID

11750532

Incident

May 28, 2026

Loss of engine power while merging or passing traffic. * Reduced acceleration making it difficult to enter highways safely. * Engine overheating if the active grille shutters fail in the closed position. * Unexpected limp mode causing sudden speed reduction in traffic. * Increased risk of a rear-end collision due to loss of power or reduced speed. * Check engine light and warning messages distracting the driver. * Vehicle stalling while driving or at intersections. * Reduced visibility if the defroster or HVAC performance is affected by engine temperature issues. * Potential engine damage from overheating, creating a hazard if the vehicle becomes disabled on the roadway. The active grille shutter system malfunctioned and caused warning lights to illuminate. I am concerned that the shutters remaining closed could lead to engine overheating or reduced vehicle performance while driving, increasing the risk of an accident due to loss of power or unexpected vehicle behavior in traffic.

NHTSA ID

11750443

Incident

Jun 2, 2026

The contact owns a 2021 Chevrolet Silverado 1500. The contact stated that while driving at an undisclosed speed, the message that the rear seats were occupied and that the windows were rolled down was displayed, which required the contact to press the OK button. The vehicle was taken to the dealer where it was purchased, but no assistance was provided. The traction control and the ABS warning lights were illuminated while depressing the brake pedal. Additionally, the cruise control mode was inoperable. The contact replaced the brake pedal position sensor independently, and the vehicle was taken to an independent mechanic, who reprogrammed the sensor. The contact stated that after the repair, the brake lights erroneously illuminated while the vehicle was turned off, causing the battery to drain. The contact disconnected and reconnected the battery, which reset the vehicle; however, the failure recurred. The vehicle was not further diagnosed or repaired. The manufacturer was not contacted. The failure mileage was 110,881.

NHTSA ID

11750243

Incident

Aug 30, 2025

Mileage

110,881 mi

Vehicle experienced sudden power steering failure and needed to be towed. A list of preceding error codes presented upon diagnostic review including power steering motor circuit, control module power circuit low input/low voltage, steering failure mitigation, power steering malfunction, lost communication with power steering control module to name a few. Dealership traced it back to a known GM part issue with the body to chassis ground strap identified in GM consumer satisfaction program N252515590 in Chevy and GMC 1500 2019-2024 models. The identified strap corrodes causing electronic failure noted above and documented by the dealership. The CSP was issued in January 2027 and is in effect until February 2028 however the dealership charged my out of pocket $384.48 for labor for a $13.40 part. My GM platinum protection plan also refused to cover the cost of the know defective repair.

NHTSA ID

11748065

Incident

Jun 30, 2026

Check engine light flashes when pulling a load and accelerating above 50mph. Check engine light code is PO300 Random multiple misfires. Took it to the shop and there we’re currently no active misfires.

NHTSA ID

11745433

Incident

Jun 17, 2026

When i first purchased the vehicle off the lot a few years back (its a 21, so probably in 22?) Brand new off the lot minimal miles. Within the first few months we started having issues with the power wanting to shift down. We took it in, the dealership found nothing wrong with it and cleared the codes. This happened a few more times. The last 2 times I took it in. They mentioned that there were recalls on it and could possibly be causing the issue. Took care of that (last august- have docs. to prove it as along with what they did and what we stated). Fast forward now 2 months ago (April of 25) and it starts acting up again and wants to downshift, shifting hard, stuttering and not wanting to drive, the same things we have been complaining about since beginning with lights on etc. However, this time we tried to shut it off and give some down time to get back home. After about 10 mins, we went to start the truck to get it home, and it would not start. We had it towed to the dealership. Once they got it, after 2 weeks of waiting we were finally presented with, the starter went out and the wiring box needed to be replaced (this has to be done before they can look into the original problem again) (because without those 2 things fixed, they wont be able to do) it is now June. I took the vehicle home, due to not having funds to fix right away. After doing some research and some digging, it would appear that the issues that we are having with the truck are issues that are already being recalled on this specific truck and model. However, for mine it is not, because I have the 2.7 l turbo and not the 6.8. THere have been numerous complaints about the known issue.(which i found out is the other wiring by the engine that is being chafed which is causing the wires to break and causing the other box and alternator to go and be replaced). If you replace it fries all again. Why is the 2.6 engine problem thats reported not recalled but rest is and it is known. I also see this online

NHTSA ID

11742660

Incident

Aug 8, 2025

1. An electrical failure from a component of the main wiring harness causes the ECM to respond with Service ESC, Reduced Engine Power, Service parking brake, service traction control. 2. Interstate driving requires maintaining rate of speed to avoid collision. The vehicle is much more difficult to drive as acceleration is very poor and also main safety functions like traction control are disabled. 3. Check engine light stays on until codes have been read. After codes have been cleared, normal driving and usually turning or bumps in the road tend to trigger the recurrence. 4. The vehicle has only been reviewed by the dealership for this issue. 5. No warnings before the failure occurs

NHTSA ID

11741419

Incident

Apr 19, 2026

1. An electrical failure from a component of the main wiring harness causes the ECM to respond with Service ESC, Reduced Engine Power, Service parking brake, service traction control. 2. Interstate driving requires maintaining rate of speed to avoid collision. The vehicle is much more difficult to drive as acceleration is very poor and also main safety functions like traction control are disabled. 3. Check engine light stays on until codes have been read. After codes have been cleared, normal driving and usually turning or bumps in the road tend to trigger the recurrence. 4. The vehicle has only been reviewed by the dealership for this issue. 5. No warnings before the failure occurs.

NHTSA ID

11741416

Incident

May 31, 2026

Once I disengaged the auto stop on my vehicle, I would accelerate from a stop and I would loose my brakes. This happened several times. I took it to the shop and was told it was fine. Finally, one day I was descending on an overpass, disengaged my auto stop and my brakes were complete failure, even my emergency brakes, my check engine light engaged (the code read emissions issue). Was able to stop in a field, get it back to the dealership to find out I lost the master break cylinder but no indication on prior visits. The truck, check engine light will spontaneously start blinking but hold no codes. I have had it routinely serviced and it will overheat and oil will run hot but mechanics find no issues

NHTSA ID

11737957

Incident

Oct 21, 2025

I am submitting a formal safety complaint regarding an electrical system failure on my 2021 Chevrolet Silverado with approximately 61,000 miles. I brought the vehicle to Taylor Grubaugh Chevrolet of Waynesville after the check engine light illuminated. The dealership diagnosed a premature wiring harness failure caused by chafing. They also stated that this issue is known to affect multiple GM vehicles and is documented in Technical Service Bulletin 21 NA 149. Wiring harness failure presents a significant safety concern. A compromised harness can lead to erratic electrical behavior, reduced engine performance, stalling, or sudden loss of power while driving. With that the concern a possible vehicle malfunction or losing power in traffic came to light. The dealerships service department confirmed the problem, verified the wiring harness failure, & referenced the applicable GM technical bulletin. The vehicle was inspected by the authorized Chevrolet dealership. GM declined to cover the repair. No police, insurance, or other third party inspections have been conducted. Despite acknowledging that this is a documented & recurring issue across GM models, the GM informed me that the repair would not be covered under warranty or recall. At only 61,000 miles, a wiring harness failure due to chafing is not consistent with normal wear & tear & instead suggests a premature defect. Given that this is a known and documented defect, I believe it should be recalled. After further research, I discovered that this issue is far from isolated. There are more than 1,500 complaints filed with the Better Business Bureau and approximately 800 complaints submitted to NHTSA reporting the same or similar wiring harness failures across GM vehicles. The volume of complaints strongly suggests a widespread defect that may pose ongoing safety risks to consumers.

NHTSA ID

11737889

Incident

Mar 31, 2026

The contact owns a 2021 Chevrolet Silverado1500. The contact stated while driving the vehicle he felt shuttering and noticed his automatic start does not start. The contact also experienced engine reduced power issues, preceded by a warning sign on the dashboard stating "Engine Power is Reduced" while driving. Additionally, the contact noticed a significant loss of mileage per gallon and a loss of oil. The contact noticed a check engine light on, which had codes that had a crankshaft and cam shaft sensors that are not operating properly, which the vehicle cannot be inspected due to the failure. The vehicle was taken to a dealer where it was diagnosed to need a new timing chain to control on the cams and crankshaft. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 110,000.

NHTSA ID

11737050

Incident

Mar 28, 2026

Mileage

110,000 mi

Two grounding straps failed on my 2021 Silverado Trail boss lt. GM has a recall for this exact problem under N252515590, model years 2019-2024. Apparently my vin number is not associated with this recall, yet my dealer just did the recall repair. They said my truck did not qualify for the GM recall and I was forced to pay for the repair. The failing grounding straps caused my power steering to go out and my brake system and safety traffic sensors to fail as well. This was very dangerous as it would fail randomly while driving the truck. There were no warning signs or lights on the the truck to indicate any problems.

NHTSA ID

11735461

Incident

Apr 14, 2026

The contact owns a 2021 Chevrolet Silverado 1500. The contact stated that the vehicle had experienced several electrical failures, including the door locks erroneously unlocking and locking while driving, and occasionally, the ignition key could not immediately be removed from the ignition switch after turning off the vehicle, causing the battery to drain. Recently, the vehicle failed to immediately start after inserting and turning the key inside the ignition switch. The cause of the failures was not yet determined. The manufacturer was notified of the failures, but no assistance was offered. The local dealer was not contacted. The failure mileage was approximately 60,000.

NHTSA ID

11731810

Incident

Nov 1, 2025

Mileage

60,000 mi

I am filing this safety complaint regarding a documented engine wire harness chafing defect in my 2021 Chevrolet Silverado 1500 with the 2.7L L3B Turbo engine. While driving, my truck experienced erratic acceleration, engine throttling to 3,000 RPM without returning to idle after releasing the accelerator, engine misfires, sudden loss of engine power, stalling, and multiple simultaneous warning lights. These conditions created immediate safety and collision risks on public roads. GM issued TSB 21-NA-149 in June 2021 and a second bulletin September 17, 2021, both before my November 2021 purchase, identifying wire harness chafing in the L3B engine caused by a manufacturing error. A wire harness clip was removed during production creating an uncontrolled harness branch that contacts sharp edges on the ECM/TCM bracket, upper control arm, and shock tower during normal engine vibration. This defect was built into the vehicle at the factory and was never disclosed to me at point of sale. The defect manifested after warranty expiration causing cascading failures; wire harness, catalytic converter, and transmission, all within five weeks. Vehicle has been inoperable since January 8, 2026. Defect confirmed by independent mechanic and by Ancira-Winton Chevrolet (authorized GM dealer) in their own repair documentation referencing GM Bulletin 21-NA-149. Dealer documented catalytic converter failure as consequential damage from wire harness repair. GM created Customer Satisfaction Program N192219370 for this exact defect. My VIN was excluded despite experiencing identical symptoms. No safety recall has been issued. Loss of throttle control and stalling at highway speeds represents an imminent collision risk. I request NHTSA investigate a formal safety recall for 2019-2023 Silverado 1500 and Sierra 1500 vehicles equipped with the L3B engine.

NHTSA ID

11730279

Incident

Feb 1, 2025

The electronics freeze up and sometimes the stereo turns off and won't come back on. The transmission perks and then revs up then hits gear and kicks real hard. The transmission feels like it's going to vibrate out from under the truck going down the road at certain speeds!

NHTSA ID

11726827

Incident

Mar 24, 2026

My 2021 Chevrolet Silverado, with approximately 84,000 miles, experienced a premature and catastrophic transmission failure while driving. The vehicle began to shudder severely and lost its ability to accelerate properly, creating an unsafe driving condition. I was able to get the vehicle to a dealership. The dealership diagnosed a complete torque converter failure requiring a full transmission replacement. Crucially, at no point before or during this failure did the vehicle's onboard diagnostic systems provide any check engine light or warning message. A sudden loss of power and transmission function on a highway is a major safety risk. I believe this is a widespread defect that needs to be investigated before it causes a serious accident.

NHTSA ID

11722588

Incident

Feb 9, 2026

2021 Silverado tailgates often stop working due to a faulty, corroded electronic switch caused by water intrusion. A major 2020-2024 GM recall exists for this, which can cause unexpected opening. Check for corrosion in the tailgate switch/connector, a pinched wiring harness, or check for a blown fuse. This is the 2nd time my truck is at ganley Chevy in Cleveland Ohio. They already fixed 1 rotted wire due to corrosion. And now having same issue again that tailgate won’t open. They told me approximately 1000.00 to find and MAYBE fix the problem. This truck should be included in the recall as to it falls under the year of the issues and that it’s the same EXACT ISSUES AS LISTED Again they have my truck in shop and I feel my truck falls under the recall proximity of said items.

NHTSA ID

11722513

Incident

Feb 4, 2026

Window switch failed and I was unable to roll down the window. Dealer confirmed and performed repairs. Problem occurred on a dry day with no previous issues and the dealer stated it was manufacturing defect with the switch.

NHTSA ID

11720033

Incident

Oct 11, 2022

I just bought this truck off a used car lot certified dealer and I noticed the engine light on then the truck would hesitate to start and I know the battery is dying so I looked it up and I got a recall on 2021 Chevy Silverado just like mine just wondering why mine is not under recall or why won’t mine get fixed but everybody else is the same year in the same problems can get fixed. I think mine should be fixed.

NHTSA ID

11718166

Incident

Feb 1, 2026

Check engine turned on and at the same time the vehicle turned into safety mode abruptly, it slowed down to 10 miles an hour while on the high way and receiving a message stating that the "engine power reduced", the issue was presented to the dealership and they believe to be fixed with a sensor issue, the light came back on a few days after the initial repair and once again the engine lost power while driving the vehicle, the vehicle was then taken back to the dealership for repair once again, both times I mentioned the service bulletin, which they did not consider in their repair, stating that the issue was specific for a code (which all codes present are in the service bulletin) the 2nd repair was done on a actuator, which they stated should fix the issue, and did not, a 3rd time the vehicle lost power while hauling a trailer, this time I brought up the concern of them not reviewing the service bulletin, this time they confirmed that the service bulletin was the issue causing the check engine light (GM service bulletin no: 21-NA-149) now they are looking to slowly start repairing the issue and wait for the check engine light to turn on again to then go back and forth and review step by step the instructions in the bulletin.

NHTSA ID

11716340

Incident

Jan 16, 2026

The vehicle has an electric tailgate lock switch failure/defect. The tailgate unlocks on its own and pops open while driving, at stop lights, in drive-thru restaurants, and while parked which causes a safety hazard to the driver and passengers in the vehicle, as well as other drivers around the vehicle. Even after closing the tailgate, it will unlock and pop open on its own again. Then, I tested the closed, locked tailgate by shacking and pulling it open from the top edge which caused the tailgate to unlock and open on its own. This causes a thief risk of personal belongings and vehicle parts. There are no warning lamps or messages about the component failure. Since no recalls for the vehicle's VIN number are listed, it has not been confirmed by the dealer.

NHTSA ID

11715521

Incident

Jan 30, 2026

The tailgate randomly opens and closes during driving causing contents to fall out of the tailgate and creating a hazard for other motorists and damaging personal property. The tailgate now will not open and there is no manual override to open the tailgate. Certainly a design flaw and now not allowing access to the tailgate. I've contacted 5 local gm/chevrolet dealer service departments and they cannot offer any guidance on how to manually or power open the tailgate. I have a tonneau cover on the tailgate which makes it pretty much unable to access. I'm a firefighter and put my gear in the tailgate and need access asap. Please advise on how I can get GM/Chevy to assist with this issue. A police officer was behind me when the contents fell out of the tailgate on 6/9/25. This has happened several times since and most recently on 1/17/26. This needs addressed asap. Thanks!

NHTSA ID

11713846

Incident

Jun 9, 2025

1- Tailgate keeps opening by itself. It has opened while driving down the highway and things fell out of back of my truck almost causing an accident. It has opened while sitting in my driveway after I have turned the truck off and gone inside. I have reported this to a dealer they said my vin is not on the recall list. I would like my VIN added since it is obviously an issue with the Silverado's. 2- I recently has to bring my truck to the dealer for the transfer case sounding like there were bolts in a blended and a pinging sound by the bell housing while in park. They stated it was the front axle and fixed it saying it was a power train thing. The noise is back and now out of warranty.

NHTSA ID

11710866

Incident

Dec 7, 2025

A week or two before I took my truck into decorah Chevy isr because tailgate was going up and down all by itself while I was driving or parked without me by it. They said it was just the latch button . So they fixed it they said and still my blinker lights would just come on and then I hit a deer and my seatbelt did not latch and my airbags didn't deploy even though my app says they did. I'm wondering if all three are connected with electrical . Either way my air bags did not deploy and my truck has extensive damage and my seatbelt didn't lock ,

NHTSA ID

11707687

Incident

Dec 23, 2025

The vehicle has been showing a “shift to park” message error upon shutdown even though the vehicle is fully in park and door automatically unlock when parked. This has left the accessories on and drained the battery

NHTSA ID

11705469

Incident

Nov 28, 2025