Another 2011 Tahoe won’t crank

[Doubeleive]

Well new problem. Now when it sits idle for 10 or 15 minutes all power shuts off and you have to turn the headlights on and it will resume. Anti theft light on and I’ve tried the key relearn 3 times with no success. I think it’s time for it to go to the dealer.

if you are referring to it idling on autostart for 10 minutes that is the most it will do until you cycle the key, I guess you can do (2) 10 minute idles if you needed to then you would have to cycle the key, the security light being on is a problem though. from what I understand a new security module can be relearned and should not require a trip to the dealer (according to the serivce manual that I got the instructions from that is the procedure) after that is done you may have to relearn any spare keys which is a quick 2 second procedure. I will find out for certain because I ordered one for my truck off ebay $34.00

 

[OLEJOE]

Less than a year. I had it load tested. Good. Been on a charger over a week while we did the testing and key relearns. Did the full relearn 3 times today. No go. Friend bringing a car hauling trailer in the morning with a winch. Signs made. Another Quality GM Product. No it won’t crank or turn over with the remote start or the key.

 

[thompsoj22]

It’s not a power issue. Scanner will connect to everything but the ECM, BCM and TCM. I can pull up information on the theft Deterrent Module. Power pins are powering. I need a wiring diagram or need to know which pin on the ECM or BCM is supposed to connect to the diagnostic tool connector. Thanks


I cleaned the cable ends and the maxifuse. If the ECM isn’t getting power, it has to be between the fuse and the ECM in the wiring. The truck will crank intermittently but will only run 3-4 seconds.

Whatever it is, It's scary! I allways try to keep it simple, There must be a common link

Less than a year. I had it load tested. Good. Been on a charger over a week while we did the testing and key relearns. Did the full relearn 3 times today. No go. Friend bringing a car hauling trailer in the morning with a winch. Signs made. Another Quality GM Product. No it won’t crank or turn over with the remote start or the key.

I absolutely get your frustration, It really isnt a GM quality issue. A TECH with the experience/ability/pub's and scanner will have it isolated within an hour unless it is in the rabbit hole of broken harness wires. These vehicles are self diagnostic, even the fact that BCM,TEHCM,ECM will not communicate is a clue that probably sends up a flag to an experienced tech. The dealer is a great option in these situations so drop it off knowing the mystery will be solved and you can go back to enjoying your vehicle. Ill guess it is in the steering column ign switch/key reader or main fuse box under the hood. I know it is a longshot but im a mech and have to make experienced decisions everyday with naysayers just waiting for me to be wrong! My guess is based upon it starting for 2-3 seconds and than shutting off. Theft deterrent if bad should produce a "no crank" at all? It's a power problem, Im probably about to get my ass handed to me again, Post your dealer results!

 

[OLEJOE]

I carried it to a friends shop. He’s good and if it doesn’t need a part it doesn’t get it. He’s got 10 bays and they stay full. I’ll report back when I hear something. The theft Deterrent Module kicked in and illuminated the light on the dash. Tried the relearn 3 times and no go.

 

[OLEJOE]

Shop just called and they have it ready. ECM took a crap. See how long this lasts.

 

[thompsoj22]

Shop just called and they have it ready. ECM took a crap. See how long this lasts.

I have so much to learn about my tech2, this was a perfect example of me trying to "guess old school" only to have my ass handed to me again!If it were mine i would have been elbow deep in the column/fuse box creating collateral fubar and the ECM was just sitting there laughing the whole time! Glad you got it fixed, I wish i knew how they isolated it without communicating with the scanner? I need tech2 tutorials!