Won't start ?

greg sudderth · September 8, 2020

Same issue with my 2020 GMC Sierra. First happened 3 weeks after purchase. Drove 4 miles to local store. Finally started after 3 tries, 15 minutes later and with "low battery, start engine" message across dash cluster. Called sales rep and service rep and said you can bring it in but same old "if there aren't any code alerts" it will be a wasted service trip

Happened again one month later after 2 mile drive to post office. Started after 3 failed attempts. Immediately called the service manager at dealer who said "well you know, these new units are loaded with modules and when you take a short drive after the car has been parked for a while, those electronic modules don't have enough boost to become fully charged and that's what's causing the vehicle to not start." So logically my response was "so are you telling me the car is not engineered to make short trips?" Long story short the dealership said I need to put more miles on the vehicle regularly! Great answer! Net-net: spend $60k for new vehicle that won't start. Look for a recall to address typical GM piss poor engineering!

Jayman556 · September 9, 2020

My son just bought a 2020 GMC Elevation and this started happening with less than 1000 kms on it. Has anyone got this issue resolved yet?

Colossus · September 9, 2020

On 9/7/2020 at 8:33 PM, greg sudderth said:

Same issue with my 2020 GMC Sierra. First happened 3 weeks after purchase. Drove 4 miles to local store. Finally started after 3 tries, 15 minutes later and with "low battery, start engine" message across dash cluster. Called sales rep and service rep and said you can bring it in but same old "if there aren't any code alerts" it will be a wasted service trip

Happened again one month later after 2 mile drive to post office. Started after 3 failed attempts. Immediately called the service manager at dealer who said "well you know, these new units are loaded with modules and when you take a short drive after the car has been parked for a while, those electronic modules don't have enough boost to become fully charged and that's what's causing the vehicle to not start." So logically my response was "so are you telling me the car is not engineered to make short trips?" Long story short the dealership said I need to put more miles on the vehicle regularly! Great answer! Net-net: spend $60k for new vehicle that won't start. Look for a recall to address typical GM piss poor engineering!

Welcome to more goodies in vehicles = more problems. Sorry you have to deal with it, but yes, all these newer modern vehicles are not meant to be occasional grocery getters and no other use. I'd recommend having a battery tender installed. Plug it in at home, unplug when you need it 5 days later, and so on. Also invest in a good jump pack.

1997SierraSLT · September 9, 2020

Or, trade it for a Tundra so you can actually enjoy life while driving a bulletproof and reliable vehicle. You won't need to invest in a scan tool or a jump pack either.......

Edited September 9, 2020 by 1997SierraSLT

NHM25 · September 9, 2020

On 9/7/2020 at 7:33 PM, greg sudderth said:

Same issue with my 2020 GMC Sierra. First happened 3 weeks after purchase. Drove 4 miles to local store. Finally started after 3 tries, 15 minutes later and with "low battery, start engine" message across dash cluster. Called sales rep and service rep and said you can bring it in but same old "if there aren't any code alerts" it will be a wasted service trip

Happened again one month later after 2 mile drive to post office. Started after 3 failed attempts. Immediately called the service manager at dealer who said "well you know, these new units are loaded with modules and when you take a short drive after the car has been parked for a while, those electronic modules don't have enough boost to become fully charged and that's what's causing the vehicle to not start." So logically my response was "so are you telling me the car is not engineered to make short trips?" Long story short the dealership said I need to put more miles on the vehicle regularly! Great answer! Net-net: spend $60k for new vehicle that won't start. Look for a recall to address typical GM piss poor engineering!

Check some of my previous posts. Try tightening the UBC bolts on your fuse box. This was the issue with my truck. Once tightened, i haven't had a single issue.

Colossus · September 12, 2020

On 9/9/2020 at 1:18 AM, 1997SierraSLT said:

Or, trade it for a Tundra so you can actually enjoy life while driving a bulletproof and reliable vehicle. You won't need to invest in a scan tool or a jump pack either.......

Who says they are bulletproof? They have their issues too.

La_RST · September 29, 2020

I have had this issue a few times on 2020 RST. Check engine light stayed on yesterday long enough for me to get to a dealer. They hooked it up and said there's a service bulletin out now for this issue. The code that pops up when they run it will be for fuel module, but the bulletin says to replace ECM. Got one ordered, we'll see..

mg2020at4 · October 2, 2020

Looks like the TSB is #PIP5733B - Replace ECM. I'm calling my dealer and having this done.

https://www.corvetteactioncenter.com/tech/knowledgebase/article/2020-corvette-pip5733b-possible-crank-no-start-or-extended-crank-with-dtc-p12a6-set-as-current-or-history-1433.html

Damon Klause · October 26, 2020

On 10/2/2020 at 12:40 PM, mg2020at4 said:

Looks like the TSB is #PIP5733B - Replace ECM. I'm calling my dealer and having this done.

https://www.corvetteactioncenter.com/tech/knowledgebase/article/2020-corvette-pip5733b-possible-crank-no-start-or-extended-crank-with-dtc-p12a6-set-as-current-or-history-1433.html

Just had my CEL the other day. Dealer said they got the bulletin Oct. 5th for this issue. They said the code can be pulled from history for this problem. Don't remember the code he specified but my truck had it. They are ordering me a new ECM.

For clarification I bought my 2020 TB Custom in Feb, had issues from Feb-April, then it went away. On Oct 14th I had crank but no start with key, then was able to start with remote. On Oct 23 I got a CEL and it went away the next day.

I will try to update.

Chris Dubois · October 31, 2020

Add me to the list. 2020 RST 3.0 Duramax. 1100 miles on it and I have had the crank no start issue about 10 times. Got it on video once. I just got it back from the dealer with no resolve. Mine will crank for about 15 seconds then stop. It has started the very next attempt every time. No CEL or codes thrown. I have noticed the voltage gauge does fluctuate quite a bit. All fuse block wires are tight. I mention the ECM bulletin to the service dept., but without the codes they didn’t do anything.

Edited October 31, 2020 by Chris Dubois

flipside82 · November 6, 2020

Jumping on this topic as well now. I have a 2020 1500 Custom 4.3L having similar issues. I first starting having the issues with less than 500 miles on it. I was at the drive thru picking up dinner and the engine just shut off. Turned the key off and back on, twice, and then it started up. I noticed it was idling funny before it shut off. The next day driving to work I had a hard shift and then the message on the dash came up saying, Steering Assist is Reduced, Drive with Care and the RPM gauge stopped working. The dash message stayed on for 2 days and then went away. No other dash lights. Took it to the dealer. They couldn't find anything wrong and sent me back home. A couple days later. Engine stops at a red light. A couple key turns and it fires right up. This time a check engine light is on. Call the dealership and they say bring it back in. Engine light went off before getting it into dealer and again no answers. On occasion I still get the hard shift and dash message about steering assist and the RPM gauge stopping. Then just this morning after filling tank with gas, truck shut off while filling tank. Took 4 starts to fire up. No dash lights or messages. After leaving gas station, I got a hard shift but no dash message. Getting frustrating not knowing what is going on.

jacbwils · November 6, 2020

10 minutes ago, flipside82 said:

Jumping on this topic as well now. I have a 2020 1500 Custom 4.3L having similar issues. I first starting having the issues with less than 500 miles on it. I was at the drive thru picking up dinner and the engine just shut off. Turned the key off and back on, twice, and then it started up. I noticed it was idling funny before it shut off. The next day driving to work I had a hard shift and then the message on the dash came up saying, Steering Assist is Reduced, Drive with Care and the RPM gauge stopped working. The dash message stayed on for 2 days and then went away. No other dash lights. Took it to the dealer. They couldn't find anything wrong and sent me back home. A couple days later. Engine stops at a red light. A couple key turns and it fires right up. This time a check engine light is on. Call the dealership and they say bring it back in. Engine light went off before getting it into dealer and again no answers. On occasion I still get the hard shift and dash message about steering assist and the RPM gauge stopping. Then just this morning after filling tank with gas, truck shut off while filling tank. Took 4 starts to fire up. No dash lights or messages. After leaving gas station, I got a hard shift but no dash message. Getting frustrating not knowing what is going on.

Has been stated several times in this thread and there are bulletins for the issue. Check all of the connections around the battery and distribution block. By check I mean tighten every one of them. Look for any black marks on the connections.

jnissen · November 6, 2020

Those 4 BCM screws pull the top fuse block into the lower wiring harness. Just tightening may not fix a poor connection below. I removed mine to install the fog light kit so I got an up close and detailed look at this assembly. I’m surprised GM used such a connection system but they must have their reasons.

You should see four green indicator posts near the four screws. If those indicators are not all equally sticking up to indicate engagement then their likely is a bent pin or alignment issue. Check the 4 green indicators carefully.

I would not suggest while your vehicle is under warranty removing and reseating the UBM unless your very comfortable doing so.

Hawaiian06 · November 20, 2020

Add me to the list of stranded drivers! 2020 GMC Sierra AT4, manufactured 09/20 in Fort Wayne, purchased on October 6th, less than 650-miles. The list price on this vehicle was $62K. Drove the truck to pick up lunch, when I came out, the truck would start, then immediately shut off. After a couple of tries, the starter began cycling continuously with or without my finger on the start button. I had to reengage the start button to get the starter to stop the cycling. Just after the second or third failed start, I got a text from GM that stated the following.

"Diagnostic Alert: Service the engine and transmission system in your 2020 Sierra within 1 day."

So the truck was communicating with the mother ship in Detroit. The check engine light also illuminated on the dash. Full battery power and almost a full tank of gas.

I tried to do an external start with the key fob, but it would not start. Waited about a half an hour and was able to coax it to start by playing with the gas pedal. Drove it straight to the dealership and did not turn it off so that they could run their diagnostics. I was also afraid that if I did turn it off it would not restart.

After running their diagnostics, they stated that it needed a new ECM and they had just received a tech bulletin for this issue two-days prior. I also asked them to do a check of the Under Dash Fuse Box bolts and provided them the number of that tech bulletin. They were a bit confused by this request, so I suspect they did not do all of the diagnostics.

So here I sit with a very expensive truck that is nothing more than a paper weight with no confidence in its dependability or reliability.

Oh by the way, I had already taken the truck in on a warranty issue for bed liner material sprayed all over the right taillight.