SERVICE BRAKE BOOSTER AND BATTERY NOT CHARGING WHAT DOES THAT MEAN

SERVICE BRAKE BOOSTER
Refer to Brake Warning System Description and Operation in Hydraulic Brakes

SERVICE BRAKE BOOSTER
The SERVICE BRAKE BOOSTER message will be displayed when the supplemental brake assist signal circuit is toggled at 1.0 Hz with a 50 percent duty cycle. This message is also displayed if the instrument panel cluster (IPC) does not see an alive and well signal at key on. When this message is displayed it indicates a problem with the SBA and should be serviced or replaced.

How do the power brakes work ? Good .?

Service Brake Booster Message Displayed
Step
Action
Yes
No
Schematic Reference: Brake Warning System Schematics
1
Did you review the Brake Warning System Description and Operation and the Brake Assist System Description and Operation and perform the necessary inspections?
YES - Go to Step 2
NO - Go to Symptoms - Hydraulic Brakes
2
Start the vehicle.
Is the REDUCED BRAKE POWER message displayed for 1 minute before the SERVICE BRAKE BOOSTER message is displayed?
YES - Go to Step 3
NO - Go to Step 4
3
Perform the Brake Assist System Diagnosis
Did you find and correct the condition?
YES - Go to Step 12
NO - Go to Step 11
4
Disconnect the Supplemental Brake Assist connector.
Test the ignition 1 circuit for an open or a short to ground.
Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
YES - Go to Step 12
NO - Go to Step 5
5
Test both ground circuits for opens.
Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
YES - Go to Step 12
NO - Go to Step 6
6
Test the engine on signal circuit for an open or a short to ground.
Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
YES - Go to Step 12
NO - Go to Step 7
7
Test the vehicle speed signal circuit for an open.
Did you find and correct the condittion?
YES - Go to Step 12
NO - Go to Step 8
8
Test the supplemental brake assist signal circuit for an open or a short to voltage.
Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
YES - Go to Step 12
NO - Go to Step 9
9
Connect the supplement brake assist connector.
Disconnect the instrument panel cluster connector.
Connect a DMM from battery positive voltage to the supplemental brake assist signal circuit.
Turn the ignition to the RUN position while observing the DMM.
Did the DMM flash battery voltage?
YES - Go to Step 11
NO - Go to Step 10
10
Replace the Supplemental Brake Assist pump motor assembly Refer to Power Brake Booster Auxiliary Pump Replacement .
Did you complete the replacement?
YES - Go to Step 12
--
11
Replace the instrument panel cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gages and Console.
Did you complete the replacement?
YES - Go to Step 12
--
12
Start the engine.
Does the Service Brake Booster message stay on?
Go to Step 2
System OK

Do a diagnostic test to find out what codes come up. Once the repairs are made to clear the codes, you shouldn't have any more check engine lights cycling.

Are you referring to warning lights on the dash board? The flashing battery light may mean you have a charging problem and the flashing brake light may mean you need break fluid or have an other brake issue. Take it to a service station or the dealer. Or read the owners manual.

The brake booster uses vacuum from the engine to multiply the force that your foot applies to the master cylinder.
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Your alternator is not charging or the battery is faulty. The load of the brake lights is draining the battery of the minimum charge needed to keep the engines computer running properly. If you turn on another high drain electrical item, like high beam head lights it will do the same.

Another possibility is a faulty power brake booster; applying the brakes would cause a loss of engine vacuum if the booster were faulty-this is far less likely..but possible.

Make sure that you buy a 'lifetime' warranted alternator from your parts source to avoid problems with bad alternators out of the box. I would try to return and exchange the alternator with one that tests out ok on a bench, in order to verify if the wiring in between the alternator or the alternator itself was bad.

Service brake booster would have to do with the vacuum or power booster problem around the master cylinder for the braking system. That wouldn't have anything to do with the alternator, I do not believe.

Good luck on these repairs.

In this model always has that problem because it usually falls cap oil valves and dana you the alternator is a common problem on these trucks ... Thanks

check ue alternator to see if its charging ur battery to check this start car and disconnect pos cable from battery if it shuts off its ur alternator

these are 2 separate problems

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/thomas_c50676e836a18949

Your brake booster is the heart of your power brakes. It runs off a vacuum from the intake to booster. Your brakes will still work as long as they have fluid. They'll just get stiff. It probably means you need a new one