Vacuum Booster Sensor Delete for GMT 900 Trucks

This is my write up of removing the vacuum brake boost sensor and no longer having a “Service Brakes Soon” message to clear. If you have a high lift cam, turbo charger, super charger, or other mod that changes the vacuum of the engine, you might be interested. If you converted from vacuum brake booster to hydraulic brake booster, this is highly recommended.

Write-up is attached in pdf form with links to parts and specialty tools needed.

This is what I did; not instructions. This document is for education and knowledge sharing only. It is by no means a definitive instruction manual for brakes and braking components. I assume no liabilities and/or damages, in other words proceed at your own risk.

 

I can confirm that this: https://gm.oempartsonline.com/oem-pa...-wire-13575871 is the correct harness ends / connectors to order for the BCM.

It has been over a month since I did this and everything is working great.

 

Dude this is cool. you should put this into a kit and sell it. Could make a little money and people would be happy to know they have the right stuff the first time.

 

Nice work

 

Almost 6 months now and everything is still working as it should. No message to clear and brakes perform well (no extra help from the ABS pump). Hydroboost should be factory on these. I also upgraded the rears to dual piston calipers from GMT800 Tahoe. Very happy with everything!!!

 

Over a year now, and the brakes are still performing better than I could hope for. Here is my write-up on an easy way to make your own hydraulic hose to convert to hydro-boost: https://www.performancetrucks.net/fo...g-hose-559297/

And here is my post on upgrading the wimpy single piston rear calipers with dual piston calipers from a GMT 800: https://www.performancetrucks.net/fo...s-12-a-559523/

 

I did this resistor install on my 07 Avalanche and it did nothing. Do you have any other ideas that might help? The relay clicks when I hit the brake, but service brake light is still on and as soon as I start to move, stabilatrac and traction control go off as well. My booster had two sensors in it. The one three wire vacuum sensor and a two wire that appears to be a pressure sensor. Any help would be appreciated.

 

I remember researching the second sensor (which I don't have)... unfortunately, I don't remember what it does. I don't think it is causing the "Service Brakes Soon" message, but hopefully, someone else will pipe in on this.

The resistors (which have to be the specific values in the document), are there to adjust the voltage that goes back to the ECBM. The three wire vacuum sensor has a Ground, a 5 Volt, and a Sensor Return Wires. You need to get a voltmeter to measure the voltage on the Sensor Return Wire. It should read nearly 3 Volts after you start the truck, and when you are not pressing the brake pedal. It should read about 2.4 Volts when you are pressing the brake pedal.

If you don't have a voltmeter, you can start your truck WITHOUT STEPPING ON THE BRAKE PEDAL. At this point, you should not have the "Service Brakes Soon" message. Wait a few minutes, then step on the brake pedal. If the "Service Brakes Soon" message comes on after pushing the brake pedal, the voltage is not dropping enough, or it is dropping too much.

Check your resistors... it is easy to grab the wrong one. If any doubt, you can grab a new resistor with the same color code you put on the truck, and use a voltmeter / resistor gauge to double check the resistance is correct.

Let me know how it goes...

 

I’ll check the values on the return signal. I used the resistors off your thread. I ordered them off the Amazon link as well as the plug. The plug needed to be trimmed, but worked well. Also, your original write up , the first picture showed ground to the outside, the next with the relay showing center pin. When I checked it was outside. I did however try it both ways. Looking at the bcm under the dash I used the light blue from the pink plug it is brake supply. I did see another I believe in c2 or 3 labeled brake signal.

 

Return wire, engine running 3.080, brake pushed 2.530