2020 GMC Sierra 1500: won't start

Filed Sep 3, 2026 · Engine · UT

2020 GMC Sierra 1500 AT4, 3.0L LM2 Duramax. In service 08/13/2020. Five glow plug failures on five different cylinders in under 19,000 miles, all at one GM dealer, all part 24000504: Cyl 1, 10/21/2024, 38,650 mi, P0671, RO 13714, warranty. Cyl 6, 11/05/2024, 38,793 mi, P1330, RO 26665, warranty. Cyl 4, 11/29/2024, 39,683 mi, P133B, RO 57498, warranty. Cyl 3, 01/22/2026, 52,959 mi, P0673/P06C7/P133A, RO 100951, I paid $713.38. Cyl 2, 08/26/2026, 57,466 mi, P06C6/P0672/P1339, RO 115953, GM under N232430460. The first three came within 39 days and 1,033 miles. Every RO documents the same finding: high internal resistance in the plug, circuit tests good. The failure is internal to the plug. Glow plug failure on a diesel causes hard starting, extended cranking, no-start in cold weather, and startup misfire - risk of being stranded or unable to start. GM has documented this defect three times: PIP5762 (12/2020), TSB 22-NA-027 (2/2022), Special Coverage N232430460 (1/2024). All name an inadequate camshaft housing cover baffle plate weld, and all limit the remedy to cylinder 2. On the recorded walkaround for RO 115953 the tech stated my engine serial falls inside the affected population and my earlier failures were probably the same condition. GM replaced only the glow plug. The camshaft cover GM identifies as the cause is still installed; GM quoted me $5,100 to replace it at my expense. Four of five failures were on cylinders 1, 3, 4 and 6, outside that scope. If the bad weld passes oil into the PCV and intake path rather than only the cylinder 2 glow plug well, ingested oil would reach other cylinders. No RO shows anyone inspected the intake tract, charge piping, cooler, PCV separator, a removed plug, or a glow plug well. I ask ODI to examine whether the cylinder-2-only scope of N232430460 is under-inclusive, whether replacing the plug while leaving the cause installed is an adequate remedy, and whether repeated internal failure of part 24000504 warrants a recall.

Filed Jun 8, 2026 · Electrical, Engine · MI

- the ground strap corroded and broke apart. Yes, I have the ground cable that failed, if needed for inspection. - yes!!! The truck's steering kept going in and out of manual steering and the engine reduced in speed allowed, and then the engine cut out on me completely - while I was in the middle of a busy road trying to turn onto a side street. Then the engine would not restart. - I had the truck towed on a flat bed to a gmc dealership nearby. They confirmed the issue was that the ground strap failed. They replaced the part at my cost, which fixed the issues. - yes, the dealership inspected and confirmed the issue was the corroded and broken ground strap. - yes, there were many warning messages that started to appear about 3-4 days prior to the complete failure of the electrical system. I started seeing a message about servicing the trailer brake system, and another about servicing the side detection system. Then a service power steering warning and to drive with care. The check engine light was off and on over that time. - I checked the wire connections iunder my vehicle to check for broken wires or corrosion. I did not find any. I then checked if a hard battery reset would work, but it did not. Lastly, I bought a new battery to replace the existing one, even though the existing battery had no issues even when tested under load. That resolved the issue for about 35 minutes that night and then the next morning. After that, the electrical system failed and the truck would not start. At that point I got towed in to the gmc dealership. I had to leave the truck for a weekend, and the dealership did not come up with a loaner, even though I requested one. I got the truck back on monday afternoon and everything was working fine since then. - over that weekend, I was amazed to find out about the bulletin gm released to cover only some trucks for the issue, but not others! My truck is still not covered, despite the obvious safety issues I experienced!!

Filed Jan 20, 2026 · Engine · MI

When driving at about 30 mph the truck randomly shut off and would not start or try to start. I was later told the engine crankshaft rod bearings seized.

Filed Jan 2, 2026 · Engine · FL

We were driving down the interstate at about 75 mph when a message came up that said to shift to neutral and push the start button. My husband did and it continued to drive perfectly fine, but about 6 miles down the road it did the same thing again except when he pushed the start button it did not start. I cannot begin to tell you the cause as to why it would’ve been doing that as I have never had any other issues with it.

Filed Nov 17, 2025 · Engine · WI

This is the 3rd catastrophic engine failure since purchasing this new vehicle from the dealership, the vehicle is currently at the dealership and is available for inspection. The latest diagnostic report has been attached from the dealership for reference. My safety and the safety of others was at risk with each occurrence. The 1st occurred on the interstate when a lifter rod bent causing loss of power with no warning, engine was rebuilt by the dealership. The 2nd occurred on the interstate when a different lifter rod bent causing loss of power with no warning, engine was rebuilt again by the dealership. The 3rd occurred just recently while on a highway. The engine suddenly turned off with no warning. The dash told me to put it into neutral and start again. I had to coast the truck for a long distance after the sudden loss of power in order to attempt to restart the engine. The engine would not start. The diagnostic report from the dealership states "engine is seized tight, maxi fuse is blown, needs engine replacement."

Filed Jun 3, 2025 · Electrical, Engine · MT

Loss of power steering. Loss of engine propulsion at high rates of speed. Engine would not start.

Filed Mar 22, 2024 · Fuel system · AL

13540028 Fuel Pump Power Control Module Part failed leaving me stranded and had to get a tow. When the failure occurred, vehicle would not crank and there was no forewarning. It worked and then it didn't. The part is on notional backorder and there seems to be a lot of vehicles out there with the same issue and that just with the mechanics\service departments I've contacted that have had the part on backorder for months. So the fail rate seems high and I'm sure others got stuck in a lot worse situation than me. Then GMC continues to produce vehicles with a newer similar part while not producing the same part for like new vehicles. Which will probably only compound the backorder issue when the newer vehicles eventually have the same issue.

Filed Jul 30, 2023 · Fuel system · TX

My vehicle suddenly did not want to start without any warning. I drove my truck and everything was good until I turned it on with the remote and not even a minute after it shut off. I tried turning it back on and it only cranked but would not start. I had a mechanic diagnose it and their computer gave them fuel pump error code. They said it was the fuel pump control module and that they have been getting several GM trucks of the same year having that issue. My truck has less than 36,000 miles on it to have this issue and I have seen that GM has issues with their fuel pump components so I dont understand why they have not recalled them. This is a safety concern because these trucks auto shut off when stopped at red lights and it could randomly shut off and not turn back on leaving someone stranded in the middle of the road without any warning.

Filed Dec 15, 2022 · Fuel system · TX · crash

The fuel pump module failed according to the dealer at 34000 miles . Car stop while driving. Cranks but no start. After resting it for hours I was able to start. Drive couple of miles about 39000 miles it stops middle of driving and couldn’t start anymore but still cranks

Filed Sep 24, 2022 · Fuel system · GA

The vehicle shut off while driving. It turns over fine but will not crank. Later cranks but again will shut off and not start. This could get me killed on the interstate. It is pulling trouble code P129F fuel pump power control module. This is a 2020 GMC Sierra AT4 with a 6.2 motor with 80,000 miles on it.

Filed Jan 31, 2022 · Electrical, Engine · TX

I have a lifters problem that the dealership takes more that three weeks to fixed without a loaner car, then i have electrical problems where the truck doesn't start at all without any warning and that's it's dangerous, never now where its going happen

Filed Jun 14, 2021 · Electrical · MI

Service ESC, Service Power Steering, antilock brakes disabled all flashed on information center of vehicle. Service engine light, antilock brake light, ESC, low battery all illuminated. Vehicle would not start - try to start it would go through all issues on information center. This is the same ESC issue described for 2019 Silverado and GMC Sierras.