Jump to content

Recommended Posts

Posted
2 hours ago, tbarn said:

I will guarantee you there a many more codes in the system. Need a proper scan to start with.

Proper scan?  You mean like BCM and ECM scan?  My ECM isn't doing much of anything because nothing can connect to it. 

Posted
5 minutes ago, enroberts said:

No, factory gauges. 

The two on the left are factory? Not familiar with them...

60924485-3A0F-4BE2-8B1A-09B9790E84C4.jpeg

Posted
Just now, SS502 said:

The two on the left are factory? Not familiar with them...

60924485-3A0F-4BE2-8B1A-09B9790E84C4.jpeg

Oh, sorry, those are definitely not factory lol. I actually removed them today. 

Posted

I just ordered a new starter, positive battery cable, and negative battery cable. Amazon will have it to me by Wednesday. I'll throw it all on and see what happens. If still no start, I'll put it on my trailer and tow it to the dealer for a scan and see if they have an issue connecting to the ECM too. As of now, I'm leaning towards a failed ECM. 

Posted

Proper scan with proper equipment like GM's GDS2 and an MDI . Or other high end scanner.

Posted (edited)

You have to know which modules are communicating and which are not. Then check power and ground at them. Then if they have power and ground you next check the networks. It's a process and can be fairly quick or  take a long time. Clearly, if the PCM does not have power or ground, you don't need to check the onstar module. One tip, check between the battery and right front fender for rodent damage. It's a common place for them to chew wiring. One more thing, any module on the high speed circuit can take the whole circuit down. The Onstar module is a common module to do just that. You can't just unplug a module to test. You have to jump the network circuits.

Edited by tbarn
Posted
13 minutes ago, tbarn said:

Proper scan with proper equipment like GM's GDS2 and an MDI . Or other high end scanner.

Makes sense. If the cables/starter don't resolve it, that will be my next step at the dealer. 

Posted
3 minutes ago, tbarn said:

You have to know which modules are communicating and which are not. Then check power and ground at them. Then if they have power and ground you next check the networks. It's a process and can be fairly quick or  take a long time. Clearly, if the PCM does not have power or ground, you don't need to check the onstar module. One tip, check between the battery and right front fender for rodent damage. It's a common place for them to chew wiring. One more thing, any module on the high speed circuit can take the whole circuit down. The Onstar module is a common module to do just that. You can't just unplug a module to test. You have to jump the network circuits.

Sounds like an expensive trip to the dealer for them to waste a bunch of time combing through module after module. 

Posted

Not really wasting time. You have to get to the bottom of the issue. Is the doctor wasting time diagnosing? This thing ain't no 78 Cheyene. They are complicated.

  • Like 1
Posted (edited)
59 minutes ago, enroberts said:

I just ordered a new starter,

 

It is possible for the starter to cause electrical problems, but I think it would probably have to short out internally, combined with a simultaneous solenoid failure resulting in a "stuck on" position. This would kill you battery pretty quickly. If you want eliminate the starter as a possible cause, you could disconnect the wires from the starter, and turn the ignition on. If everything works perfectly on the dash, reconnect the starter and check the dash again. You can also bench test the starter by using a car battery and jumper cables. Or you can test the stater in the vehicle by crossing the terminals with a screw driver.  

Edited by starman8tdc
  • 2 weeks later...
Posted

For those interested, my ECM failed. Replaced it at the dealer today and had it reprogrammed. Back in business!

 

On 12/15/2018 at 10:51 PM, tbarn said:

You have to know which modules are communicating and which are not. Then check power and ground at them. Then if they have power and ground you next check the networks. It's a process and can be fairly quick or  take a long time. Clearly, if the PCM does not have power or ground, you don't need to check the onstar module. One tip, check between the battery and right front fender for rodent damage. It's a common place for them to chew wiring. One more thing, any module on the high speed circuit can take the whole circuit down. The Onstar module is a common module to do just that. You can't just unplug a module to test. You have to jump the network circuits.

Sounds like an expensive trip to the dealer for them to waste a bunch of time combing through module after module. 

  • Like 1
Posted

Great. I'm sure it will help someone. Under warranty, correct?

Posted

I glad you got your truck fixed...
Happy New year.

Sent from my SM-G965U using Tapatalk

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Latest Articles

  • Posts

    • Hi friends - first time poster. I have a 2015 sierra Denali with 150k miles, I’m the second owner and she’s given me 75k of great service. I run a pulse AFM disable device. Starting Thursday when I exited the freeway after a short local ride it started idling rough, with an obvious misfire shake and was down on low end power.  I got it home and hooked it up to my scannner and found no codes but in live data a pretty bad misfire on cylinder 5. I replaced the coil, plug and wire with all new OE replacements (Delphi gn10165 coil, acdelco wire and 41-168 plug). It’s still behaving the same way after firing the parts cannon at it.   I know cyl 5 is a non AFM cylinder so I am not thinking this is AFM related but I’m kinda at a loss. injector? Bent pushrod? It’s running too well over 1k rpm to suggest those IMO. Has anyone chase this issue before and what was it? Any suggestions? 
    • 2017 Silverado L83 5.3l 6speed transmission Hello, not a new member but havent posted in a while and my old signup info isnt working so had to create a new account. anyways, I have an issue with my truck and hope someone can spread some light on whats happening: -when it goes to 4cyl mode it makes a clunk sound (but not when coasting or going downhill) -when in 4 cyl mode and under load it makes a load pulsating sound (not a tick). -goes away completely when in M5 gear or when plugging in an AFM delete. Im guessing it is one of 2 things but im not convinced of either to be honest. 1. lifter stuck in v8 mode 2. torque converter shudder realistically it doesn't seem like the TC as there is no physical vibration , and it never happens in v8 mode. but maybe? and wouldnt a lifter make a sound whether with load or not? any ideas let me know please. thank you!  
    • Which has made me wonder with the various engine failures of a few brands in the last few years, is it sub par materials such as lifters etc causing failures, or bearing clearances on the crank etc or perhaps bad designing of an engine physically or causing too much load on the components due to the hp/torque they can push out of them. Or is the oil viscosity and additive package of current oils or a lack of oil flow by an oil pump not able to supply sufficient oil at idle or under high load at low rpm. Or is it every item I listed that combined together has pushed the limits so far to the left that there is hardly a margin of safety left and add in some fuel dilution and too long of an OCI and premature engine failure is the result ?. 
    • He is not saying that an SAE *W20 will have more viscosity than a *W40 due to MORE VII polymers. He is saying that although multiple *W40 may post in the PDS the same or similar 100 C and 150 C viscosities that the blenders choice of modifier TYPE and AMOUNT to get his chosen base to grade will not give identical real world viscosities in shear and at temperature. All will pass the SII test but not all will pass the 100 C HTHS (unpublished value) testing the blender does and relies on to get the required by law "percentage improvement' referenced to his last great work.    Tis the problem with the lie. Once told others are required to support it. 
    • I have a `25, 1500 that auto sets on incline. Never knew that at first. I have the electronic shifter. Just think if it didn`t do that? Unlike a mechanical shift that you can muscle out of park, how would you get this thing out? That would be a problem.   What I found out later is, I don`t have to push the button to release. Just put it in gear.   Setting parameters? Don`t know if it`s possible.
  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...