David Crandall

Sorry I know this is nearing a year ago. Were you able to figure out how it's locked to a specific VIN??? I have an update I've been trying to unlock to use myself.

What you are reading has absolutely nothing to do with the vacuum pump, or brake booster. They are not linked together in any way. I have a similar device but am using the paid version of the car scanner app. I used torque for a long time, but like this one better. Works great for quick stuff at work to determine if I need to get the shop scanner, or basic stuff at home. It will take a more advanced scanner to read it since it will not be standard OBD II data. It's going to be read in the brakes module. The vacuum pump was added to these Ecotec3 engines to provide a constant source of vacuum to the brakes regardless of active fuel management operating mode. When they start to fail it is most evident at low speed because the pump is belt driven, so output is decreased. The vacuum check valve is still there for the same reasons it was when using manifold vacuum.

What are you using to get this reading, and what sensor are you reading for this? I think you're going to have to be looking at the ABS module to read the vacuum at the brake booster and see mechanical pump output. If you are getting this low reading only with the engine in V4 mode than you are not reading what the vacuum pump is doing. Lack of vacuum supply to operate the brakes with the engine in V4 mode is why the mechanical pump is there. Service manual specifications for engine driven mechanical vacuum pump readings are 27 in Hg or greater at idle in park with the AC off. I'm pretty sure that if the vacuum pump was producing so little vacuum you would be getting some kind of a warning to service the brake system. Previous generations of the trucks didn't have the mechanical vacuum pump and would deactivate the active fuel management system if the vacuum was too low for proper operation of the brakes.

This is what the recall was supposed to do. When the vacuum pump can't provide the needed vacuum for the brake booster the abs kicks in and provides brake assistance. If this was intermittent before then your vacuum pump was already failing. Programming has nothing to do with it, it's purely mechanical and belt driven. The only thing electronic on the vacuum system is the sensor telling the computer how much vacuum is in the brake booster. Now with the new programming the computer activates the abs system to boost you brakes when there is low vacuum and you are applying the brakes

Here's my take on the recall and the special coverage on the vacuum pump. The recall is kinda a bandaid so you will have some sort of power assistance to the brakes in the event you have insufficient vacuum to the booster. The special coverage on the vacuum pump shows they acknowledge that they are failing too much! The original letter I received informing me about it said coverage would be extended to 6 years 72k miles. If it fails within the coverage they will replace it, the recall doesn't change that. I'm a technician with the local city fleet and we have access to GM dealer level service info and bulletins. We also have a subscription to the service programming system. I ran my vin the other day and found the special coverage extended earlier this month to 10 years and 150k miles. I did the reprogramming for the recall myself at work and it only took me about 20 minutes. But that only includes setting up the computer and logging into the SPS account to do it. The tech at the dealership will probably spend twice as much time finding your vehicle on the lot, bringing it into the shop, reprogramming, parking, and doing the necessary paperwork to get paid the 0.3 hours (18 minutes) the warranty time the recall bulletin allows for. Warranty work is one of the main reasons I left the dealership almost 15 years ago. It was getting harder and harder to make my flat rate hours match the time I actually spent at work. The other is I was tired of only getting something around $20 a flat rate hour while they were charging something around $130.

There is a recall to reprogram the abs module: "Dealers will reprogram the electronic brake control module with a new calibration that will improve how the system utilizes the hydraulic brake boost assist function when vacuum assist is depleted." There is also a special warranty coverage on the mechanical vacuum pump for the brake booster, 10 years 150,000 miles

Special coverage on this pump has been updated!!! 10 years 150,000 miles. #N182202780-01: Special Coverage - Brake Assist Decreased Due to Vacuum Loss - (Oct 11, 2019) Release Date: October 2019 Revision: 01 Revision Description: This bulletin is being revised to update the models and extend the coverage period. Please discard all previous copies of bulletin N182202780 What We Have Done:General Motors is providing you with the additional special coverage outlined in this letter for the condition described above in the interests of customer satisfaction. If this condition occurs on your 2014 – 2018 model year GM vehicle within 10 years of the date your vehicle was originally placed in service or 150,000 miles (240,000 km), whichever occurs first, the condition will be repaired for you at no charge. Diagnosis or repair for conditions other than the condition described above is not covered under this special coverage program. If you were previously notified regarding this condition, please note that we have expanded the coverage. Reimbursement:If you have already paid for repairs for the condition described in this letter, please complete the enclosed reimbursement form and present it to your dealer with all required documents. Working with your dealer will expedite your request, however, if this is not convenient, you may mail the completed reimbursement form and all required documents to Reimbursement Department, PO Box 33170, Detroit, MI 48232-5170. The completed form and required documents must be presented to your dealer or received by the Reimbursement Department by November 30, 2020, unless state law specifies a longer reimbursement period.

Not sure if you found an answer or any more info about the axle in your 2013, it's been a few months. For 2014 there was a redesign of the axle. The new version of the 9.5 only has 12 bolts in the cover, and the previous versions were all 14 bolt. Parts are not directly interchangeable between the 12 and 14 bolt versions. I'm looking into upgrading my 2000 extended cab to a crew cab in the near future and have been researching the differences, also looking to make sure I end up with better towing capability as well. The only differences I can find between the 14 and up 9.5 and the 9.76 is the gears and the pinion bearings. I'm guessing the 9.76 uses larger diameter pinion bearings, leading the the different castings in the housings. I can't find all the bearing numbers to compare their sizes to verify for sure.