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Chris (aka-Moose)
Chris (aka-Moose), GMC Technician
Category: GMC
Satisfied Customers: 46875
Experience:  16 years of experience
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My 2009 GMC Sierra HD diesel recently displayed an Error

Customer Question

My 2009 GMC Sierra HD diesel recently displayed an Error message "SERVICE STABILITRACK PARK ASSIST OFF" that resulted in the truck not being able to automatically shift out of first gear while in drive and not displaying on the dash if the truck is in Park, Neutral, Reverse, or Drive. The truck was still drivable at slow speeds(first gear). This error was not occurring consistently, so the truck would drive normally at times.
The truck most recently displayed the error message "SHIFT INHIBITED SHIFT TO N TO RESET" and is no longer drivable. Whether the truck is in neutral, drive, or reverse the truck acts as if it's in neutral. Shifting to Neutral and then to other gears or turning the truck off and on did not resolve the issue. The error message has returned to the original message of SERVICE STABILITRACK but is still experiencing these new issues so the truck is currently not drivable.
Looking online, other owners of GMC Sierras experiencing this problem have found their transmission fluid was low or they needed to replace the NSBU switch, and various other solutions. Transmission fluid level seems to be normal but the NSBU switch is beyond my mechanical ability.
I would greatly appreciate any help with troubleshooting this issue, even if it's just to make it drivable enough to get it to a mechanic to resolve the issue.
Thank you for taking the time to read this message and for any assistance you can provide.
Submitted: 1 year ago.
Category: GMC
Expert:  Chris (aka-Moose) replied 1 year ago.

Welcome, I'm Chris (aka Moose). Experts aren't employees / agents of Just Answer. We are independent service providers using the Site to sell their Expert knowledge to Customers. I strive to provide EXCELLENT 5 STAR service, let me know what's needed from me so your pleased.

Your findings are correct. The warnings and symptoms point most to the neutral switch faulty. Though diagnosing it should be done prior to parts installed. Having the odes checked is first then once we know those codes we can do those diag steps.

Thanks for asking your question and letting me try to help you.

If your confused on why or how to rate me, let me know.

I'm only paid from the deposit you've made when you rate 3,4, or 5 stars.

Follow up/Reply as many times as needed before or after rating.

Expert:  Chris (aka-Moose) replied 1 year ago.

Hello again Chris here,

1) When customers come to Just Answer the website and the experts want them to have a great 5 star experience.

2) We also want them to be so pleased that they come back for future needs.

3) I have the feeling you were not pleased with my help and or need me to help more. If so please do reply.

4) I have an option to upload diagrams, repair guides, find a repair facility, or call you if that would help.

Thanks Chris

Customer: replied 1 year ago.
I appreciate the follow-up reply, Moose. Particularly points 3 and 4 where you offered other means of assistance you could provide in the event your first answer was not what I was looking for.I would like to take you up on the offer of uploading repair guides, but am not sure it would be helpful due to not knowing for certain the Neutral Switch is the problem and not having an OBD II scan tool to check the codes for confirmation. I wouldn't mind purchasing an OBD II if there was a reasonable chance I could perform the repair myself, but I have very little experience and knowledge when it comes to repairing vehicles. I've only done the basics of changing my oil, air filters, batteries, flat tires, windshield wipers and checking/topping off fluids. Do you think replacing the Neutral Switch myself is still an option considering my inexperience?As for finding a repair facility, I would be interested in any help you could offer but I've been in contact with the dealership this truck was purchased from(Stanton Tx). I would rather not pay for the towing to get the truck there but I may not have another option. Also while talking to the technician at this dealership, he suspects the Transmission Control Module based on the description I gave him via email(largely the same as my original post here). Due you think his assessment is also plausible?So I guess there are 3 main points in all:1. Repair guides may help, but am not experienced in vehicle repair.
2. Would you advise purchasing an OBD II scan tool to get the error code? Would it be within reason that I could make the repair despite my inexperience?
3. Could it also be a problem with the Transmission Control Module? If so, would it be within reason that I could make this repair?I appreciate any help you can provide and will be extremely(and pleasantly) surprised if I'm able to avoid towing the vehicle to the dealership for repairs, but I will happily rate you 5 stars even if this is the outcome as I'm just expecting exper insight, not a magical cure for my truck's problem.Thank you,Rob
Expert:  Chris (aka-Moose) replied 1 year ago.

I am sending in that request that will allow me to upload links from the repair guides.

A scan tool is always helpful for someone whom wants to fix there own cars. A lower priced one that can do most things a DIY needs, like a Bosch brand is around 200$ for a mid range unit.

If the TCM is to blame, you would need a dealer to do the repair and programming.