Recall - Vacuum Pump May Decrease Power Brake Assist

[Viffer800]

On 10/23/2019 at 10:51 AM, David Crandall said:

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

 

My theory is that the reprogramming does not play well with a worn/weak pump.

 

After the dealer did the recall fix to my 2014 Sierra, the loss of braking actually got worse.  It is worse to the point of instead of losing braking every so often that now it is consistent.  Now when moving at slow speeds and hitting the brakes, letting off, and then hitting them again, I lose all assist and in fact the ABS kicks on even at 5 mph.

 

At least no more surprised loss of braking, it's all the time now!

 

Truck is once again sitting in the dealership.  Already waiting for parts for ball joints and steering gears (all covered under extended warranty) because of the strike.  Looks like now it might be waiting for a pump, but don't know as they have not called me back yet.

 

Gawd am I thankful I still have my old 1997 Silverado.

 

 

[David Crandall]

38 minutes ago, Viffer800 said:

 Now when moving at slow speeds and hitting the brakes, letting off, and then hitting them again, I lose all assist and in fact the ABS kicks on even at 5 mph.

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

Edited October 30, 2019 by David Crandall

[15BlueSilverado]

I actually had an issue with my brakes not too long ago after the recall came out. I was backing into a parking spot and it felt like I had to push a little harder to stop the truck, even then it felt like it still rolled back slowly. Luckily I didn't hit anything but after turning the truck off and back on after a while, they felt fine again. I scheduled my truck for service the following Monday and sure enough, they said the vacuum pump was going out and replaced it at no charge since my truck was still under warranty and took care of the recalls also. Brakes have been fine ever since. 

[Viffer800]

1 hour ago, David Crandall said:

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

1) This is why I am here

2) Yikes

 

This fix actually made it worse.  At least before I could control stopping using muscle.  Now having the ABS kick in a driver looses all control over stopping. 
 

In fact the dealership took my truck away and put me into a loner because they felt the fix made it unsafe to drive. 
 

 

[durandetto]

Got my letter last week. Ignoring it for the moment. Pepper has 105 K on her now and runs like a top. I'm more inclined to just replace the pump to the superseded "improved" part... This whole recall has a fishy smell to it. 
 
Like a lifter failure where they replace the offending bank of lifters. Most guys complain about this half measure but my question is, if it is an oil pressure issue that causes the failure and you don't replace the parts that control the pressure that caused the failure is it likely to happen again? I think so.  Replace the VLOM manifold and screens and pump/jets solenoids.
 
Band-Aid on a GSW thinking IMHO.  

When I had a lifter fail they replaced all lifters, vlom, one valve, the cam and I convinced them to replace the oil pump. 2 weeks later I started having injector problems. Replaced bank 2 injectors then a week later replaced 4 and 6 again. Almost 2 weeks now and so far so good. Worried there's something else causing the injectors to fail as they were AFM injectors both times.

Sorry for going off topic, but I'd say the question has been answered pretty well.

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[durandetto]

This is the most useful thing I've heard on this site. Great stuff and THANKS!
 
I'm going to buy the pump out of pocket and pay my shop to install it and leave my ABS alone. Should they pay? Yes! BUT brakes are more important to me than getting my way. All I needed was the TRUTH. Thanks for giving me that. Now...that wasn't so hard, was it?

I had to replace my pump the week I bought my truck at 67k, thankfully I work for a repair shop so I got the part for $110 and installed it myself. Unfortunately when my truck was in for warranty work they did the software update without my knowledge.

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[durandetto]

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

That's not 100% true the abs pump is supposed to help with brake power assist not actually activate the abs as that will cause a longer stopping distance. This isn't a common use for an abs pump but there were cars back in the day that had abs pump brake boosters as their only source of power brakes. I believe it was in old GM sedans.

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[CurtK]

On 10/23/2019 at 8:27 AM, David Crandall said:

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.

Woah... I guess I need a "reimbursement form". (Now I just need to find out where to get one.) Is this a document that should be mailed out to us truck owners or is this GM internal stuff? Either way, thanks for the info! Maybe there's a chance to recoup the cost of this repair if we all follow the process. 

[CurtK]

...I did have the reprograming done at 84k. Seemed worse, replaced pump. 

[Eddie 70]

I had the recall done on my 14 this past Friday. I drove the truck home and today, Sunday was the first time I have been back in the truck. My check engine light was on. I finished what I was doing today. Several starts and stops over the day and still the check engine light is on. Tonight I checked the codes and it was P0430 and P0171. I cleared the codes, scanned the truck again. No codes. Started the truck, check engine light gone and no codes.

 

P0171 says it could be a weak fuel system or vacuum leak. Could that have been caused by the recall? That is the first time I have had any lights on the dash and it just happens to be after the dealer worked on it. Coincidence?

[Jglew82]

The brake recall is a reflash of the bcm and would have nothing to do with causing a lean bank 1 or catalyst bank 2 issue. 

[Eddie 70]

58 minutes ago, Jglew82 said:

The brake recall is a reflash of the bcm and would have nothing to do with causing a lean bank 1 or catalyst bank 2 issue. 

This was my thought too. I'm shocked that it threw the codes after the work. I guess I am going to drive it today and see if it comes back on.

[jay webb]

On 9/11/2019 at 10:45 PM, bkesting said:

So there is a newer style pump? If so, is it hard to change out?

it is an updated part. GM just updated the coverage on this to 10 yrs 150,00 so if you still are with in coverage period just go to the dealer and have it done. 

[jay webb]

9 hours ago, Eddie 70 said:

This was my thought too. I'm shocked that it threw the codes after the work. I guess I am going to drive it today and see if it comes back on.

 

On 10/30/2019 at 11:00 PM, CurtK said:

Woah... I guess I need a "reimbursement form". (Now I just need to find out where to get one.) Is this a document that should be mailed out to us truck owners or is this GM internal stuff? Either way, thanks for the info! Maybe there's a chance to recoup the cost of this repair if we all follow the process. 

just go to the dealership and speak to the service manager 

[jegreenwood14]

On 11/10/2019 at 5:33 PM, Eddie 70 said:

I had the recall done on my 14 this past Friday. I drove the truck home and today, Sunday was the first time I have been back in the truck. My check engine light was on. I finished what I was doing today. Several starts and stops over the day and still the check engine light is on. Tonight I checked the codes and it was P0430 and P0171. I cleared the codes, scanned the truck again. No codes. Started the truck, check engine light gone and no codes.

 

P0171 says it could be a weak fuel system or vacuum leak. Could that have been caused by the recall? That is the first time I have had any lights on the dash and it just happens to be after the dealer worked on it. Coincidence?

 

Had exact thing happen to me the other day after getting my vacuum pump replaced, but it wasn't code P0171.  Can't remember what it was now, but I had the light on most the day.  Cleared codes when I got home, then nothing.  No light or anything.  Running like a top right now.