3.0 Duramax cranks but won’t start

[Claxy515]

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Edited July 15, 2021 by Claxy515
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[Claxy515]

1 hour ago, ColoradoCub said:

You guys have literally read this thread, you know one owner had his truck ripped apart (per the bullshit exciter wheel bulletin) and we’re inconvenienced for at least 20+days for a problem that really isn’t that big of a problem and after all that knowing it didn’t even fix the problem but yet you still went ahead and participated in this experiment, I don’t know what to tell you! Please report back when you get your trucks back and it still does the crank no start. 

 

Agreed. Just wait it out, let them find the issue. I personally always check my foot and floormat to make sure they aren't touching the gas pedal. You'd think they'd push a time-out update so the starter would stop after 3 seconds of no ignition, instead of 20 seconds.

[GJR1212]

20 hours ago, Claxy515 said:

 

Agreed. Just wait it out, let them find the issue. I personally always check my foot and floormat to make sure they aren't touching the gas pedal. You'd think they'd push a time-out update so the starter would stop after 3 seconds of no ignition, instead of 20 seconds.

I agree that shortening the crank default time makes a lot of sense.  If  a modern engine hasn't busted off in a few seconds, more cranking is not the solution.    Also, they should get rid of the auto stop/start function (or atleast make it where the driver can decide to turn it on rather than automatically turning it on or every restart.   From what I can tell these engines are using pretty genaric starters.   All these starts will wear them and the flywheel teeth out.  

[MDyer21]

No Issues until 4.5K miles then (2) start sequence headfakes in 3 days. 2021 AT4 3.0L

 

update: 30 minutes later. (3) times in 3 days. Starting to think I should’ve kept my 07 Lincoln Mark LT w/ 256K miles 

Edited July 17, 2021 by MDyer21

[Frankhpns]

5 hours ago, MDyer21 said:

No Issues until 4.5K miles then (2) start sequence headfakes in 3 days. 2021 AT4 3.0L

 

update: 30 minutes later. (3) times in 3 days. Starting to think I should’ve kept my 07 Lincoln Mark LT w/ 256K miles 

I would think the dealer can ascertain which sensor is causing the over-crank failure to start condition. I would think it was not the camshaft position sensor problem I have due to the milage you have when the problem occurred but I could be wrong. Good luck.

[Jacob D]

I am working on trying to get out of my 1500 Sierra and switch to a F250 even losing some. After start failures, power steering not working a couple times, noisy leaf springs... I'll probably never buy another GM

[Hello32]

I have a 2021 duramax 1500 having the same issue. Dealer did and ECU update and I had the extended crank issue again today. Debating if i should take back to dealer, they kept it over a week last time and i didnt get a chance to make a video

[Frankhpns]

6 hours ago, Hello32 said:

I have a 2021 duramax 1500 having the same issue. Dealer did and ECU update and I had the extended crank issue again today. Debating if i should take back to dealer, they kept it over a week last time and i didnt get a chance to make a video

 

6 hours ago, Hello32 said:

I have a 2021 Duramax 1500 having the same issue. Dealer did and ECU update and I had the extended crank issue again today. Debating if i should take back to dealer, they kept it over a week last time and i didnt get a chance to make a video

Apparently GM had a number of the camshaft position sensor wheels which were supplied by a third party vendor defective. Some people have commented that it is no big deal, I would disagree. There are two technical service bulletins out on the problem. One was for a firmware update which did not fix the problem. The other is to replace the exciter wheel which is an extensive repair taking close to 50 hours of labor to do. 

[Joe Brooks]

#4 today at 3500 miles.  Ben trying to record my starts but missed it due to rain and moving my daughter.  Beyond frustrating it being so hit and miss.  

[ColoradoCub]

1 hour ago, Frankhpns said:

 

Apparently GM had a number of the camshaft position sensor wheels which were supplied by a third party vendor defective. Some people have commented that it is no big deal, I would disagree. There are two technical service bulletins out on the problem. One was for a firmware update which did not fix the problem. The other is to replace the exciter wheel which is an extensive repair taking close to 50 hours of labor to do. 

And if you read all the posts in this thread you’ll see that one guy had the 50 hour repair and his truck still does the crank no start, so clearly that is not the fix.

Edited July 19, 2021 by ColoradoCub

[Joe Brooks]

Does anyone know if GM has acknowledged this issue and that the exciter wheel was not the fix?   I would think they could take one of the trucks that have been replaced (one on this forum as I understood it) and plug in a computer and drive the dang thing till it happened.   That is if they acknowledge this is fairly common.  It seems a trip to the dealer is useless if they can replicate the issue at the time of the visit. Just my thoughts. 

[Frankhpns]

2 hours ago, Joe Brooks said:

Does anyone know if GM has acknowledged this issue and that the exciter wheel was not the fix?   I would think they could take one of the trucks that have been replaced (one on this forum as I understood it) and plug in a computer and drive the dang thing till it happened.   That is if they acknowledge this is fairly common.  It seems a trip to the dealer is useless if they can replicate the issue at the time of the visit. Just my thoughts. 

Quite frankly I don't know. The fault code indicates that the camshaft sensor exciter has failed. The TSB tells the mechanic to borescope the exciter and sensor and if it is bent replace it. I would think that would fix the problem.  There may be other issues preventing the vehicle from starting but I would have thought they would have shown up when they did the diagnostic check.

[ColoradoCub]

3 hours ago, Frankhpns said:

Quite frankly I don't know. The fault code indicates that the camshaft sensor exciter has failed. The TSB tells the mechanic to borescope the exciter and sensor and if it is bent replace it. I would think that would fix the problem.  There may be other issues preventing the vehicle from starting but I would have thought they would have shown up when they did the diagnostic check.

Guy there is a guy on this thread that walked us all through having the entire TSB for the exciter wheel done and still has a crank no start, why would you think it would still be the fix?

[Frankhpns]

1 hour ago, ColoradoCub said:

Guy there is a guy on this thread that walked us all through having the entire TSB for the exciter wheel done and still has a crank no start, why would you think it would still be the fix?

The fact that one individual has the same symptoms after the TSB recommendation was performed is not statistically significant enough to confirm that the exciter wheel replacement is not the problem. Could be a myriad of secondary problems including a bad repair due to a defective new sensor.

[ColoradoCub]

2 hours ago, Frankhpns said:

The fact that one individual has the same symptoms after the TSB recommendation was performed is not statistically significant enough to confirm that the exciter wheel replacement is not the problem. Could be a myriad of secondary problems including a bad repair due to a defective new sensor.

That’s not a very logical response. Customer has problem A, GM says repair B fixes it. Repair B is completed and customer still has problem A. Your logic is that the repair was not done correctly?? And remember he’s not just one individual, he is THE individual that the TSB was created for, pictures on the bulletin are of his engine!!! Geez!! And what about all the trucks that don’t have a bent trigger wheel after being inspected but have the same crank no start, are you implying that a problem plaguing many 2021 trucks identically is being caused by multiple things?

Edited July 20, 2021 by ColoradoCub