'03 Silverado Ls "service Brake Booster" Pump Running

[Bunky8150]

My vehicle is an '03 Silverado 1500 LS with factory towing package. It has 49,000 mi I have owned it since 13,000 mil. The vehicle is in very good condition.

 

Yesterday, after a 70 mile highway trip, I applied the brakes and at slow MPH speed, a running pump sound came from under the hood. Within a few seconds, "Service Brake Booster" error message appeared on the dash. The pump continued to run for another 5 minutes until the vehicle was shut off.

 

When I re-started the truck, the pump noise began again for a few seconds and stopped. The message appeared then cleared itself. Again today the same pump noise and message happened until I shut off the ignition.

 

I have checked for loose vacuum lines and found none. The brake function did not seem to be affected. What could be the problem?

[jro909]

had similiar problem with the message showing up alot...ended up needing a pcm update

[Bunky8150]

How do I diagnose this item to determine if it is a bad pump, check valve or booster?

[Bunky8150]

I blocked off the hose from the pump and the pump with no difference in problem. I pulled the pump from the brake booster and heard a vacuum rush. The booster and the pump appear to be holding hg.

 

Where is the check valve located? How can I check the pump for vacuum hg?

[jro909]

your computer might just need an update

[Bunky8150]

I just found my rear brake lights are not working but the center light does work so the brake switch is working. The four way flashers work so the bulbs are good. The fuses are good.

 

Now What?

[Doug_Scott]

I just found my rear brake lights are not working but the center light does work so the brake switch is working. The four way flashers work so the bulbs are good. The fuses are good.

 

Now What?

 

You may want to take a look at the turn signal switch or flasher. No idea how the 03 is wired, but it was not uncommon back when I was actively working as a mechanic (pre 1990) for a defective turn signal switch to cause the brake lights to not work on GM vehicles.

[Bunky8150]

Does the turn signal control module ($76 dealer list price) have anything to do with the electric vacuum booster pump and the bed mounted brake lights?