Brake Booster Pump Motor Malfunction
|
|
Brake Booster Pump Motor Malfunction
|
|
Diagnostic Fault Information
|
|
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Brake Booster Pump Motor B+
|
1
|
1
|
-
|
-
|
Brake Booster Vacuum Sensor Ignition
|
1
|
1
|
-
|
-
|
Brake Booster Pump Control
|
1
|
1
|
2
|
-
|
Brake Booster Pump Ground
|
-
|
1
|
1
|
-
|
1. Brake Booster Pump Always Off
2. Brake Booster Pump Always On
|
|
Circuit/System Description
|
The brake booster vacuum switch monitors the amount of vacuum available to the power brake booster. When the vacuum within the system drops, the switch within the brake booster vacuum sensor closes allowing voltage to be supplied to the brake booster pump motor.
Schematic Reference
Hydraulic Brake Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Brake Booster Vacuum Assist Description and Operation
Electrical Information Reference
|
1.
|
Inspect for leaks around the pump and the supply lines.
|
|
2.
|
If a leak is located, tighten or replace any leaking lines or components.
|
|
3.
|
Ignition OFF, disconnect the KR14 Brake Booster Pump Motor Relay.
|
|
4.
|
Verify a test lamp illuminates between the B+ circuit terminal 5 X1 and ground.
|
|
5.
|
If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the X50A Fuse Block - Underhood.
|
|
6.
|
Test for less than 5 Ω between the ground circuit terminal 1 X1 and ground.
|
|
7.
|
If greater than the specified range, test the ground circuit for an open/high resistance.
|
|
8.
|
Disconnect the harness connector at the B19C Brake Booster Vacuum Switch.
|
|
9.
|
Verify that a test lamp does not illuminate between the control circuit terminal 2 and ground.
|
|
10.
|
If the test lamp illuminates, test the control circuit for a short to voltage.
|
|
11.
|
Test for less than 5 Ω between the B19C Brake Booster Vacuum Switch control circuit terminal 2 and KR14 Brake Booster Pump Motor Relay control circuit terminal 2 X1.
|
|
12.
|
If greater than the specified range, test the control circuit for an open/high resistance.
|
|
13.
|
Test for infinite resistance between the B19C Brake Booster Vacuum Switch control circuit terminal 2 and ground.
|
|
14.
|
If less than the specified range, test the control circuit for a short to ground.
|
|
15.
|
Verify that the corresponding ignition circuit fuse is okay.
|
|
16.
|
If the ignition circuit fuse is open, test all the components connected to the ignition circuit and replace as necessary.
|
|
17.
|
Ignition ON, verify that a test lamp illuminates between the B19C Brake Booster Vacuum Switch ignition circuit terminal 1 and ground.
|
|
18.
|
If the test lamp does not illuminate, test the circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the X50A Fuse Block - Underhood.
|
|
19.
|
Connect a 10 A fused jumper wire between KR14 Brake Booster Pump Motor Relay B + circuit terminal 1 X2 and B+. Connect a 10 A fused jumper wire between KR14 Brake Booster Pump Motor Relay ground circuit terminal 2 X2 and ground. Verify the M9 Brake Booster Pump Motor activates.
|
|
20.
|
If the M9 Brake Booster Pump Motor is not active, test the KR14 Brake Booster Pump Motor Relay ground circuit terminal 2 X2 and the control circuit terminal 1 X2 for an open/high resistance. If the circuit tests normal, replace the M9 Brake Booster Pump Motor.
|
|
21.
|
Remove all fused jumper wires. Connect KR14 Brake Booster Pump Motor Relay to the harness connector. Connect a 10 A fused jumper wire between B19C Brake Booster Vacuum Switch control circuit terminal 2 and B+. Verify the M9 Brake Booster Pump Motor activates.
|
|
22.
|
If the M9 Brake Booster Pump Motor is not active, replace the KR14 Brake Booster Pump Motor Relay.
|
|
23.
|
If all circuits test normal, test or replace the B19C Brake Booster Vacuum Switch.
|
|
24.
|
If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the X50A Fuse Block - Underhood.
|
Brake Booster Pump Motor
|
1.
|
Ignition OFF, disconnect the harness connector at the KR14 Brake Booster Pump Motor Relay.
|
|
2.
|
Connect a 20 A fused jumper wire between the B+ terminal 1 X2 and B+.
|
|
3.
|
Connect a 10 A fused jumper wire between the control terminal 2 X2 and ground.
|
|
4.
|
If the M9 Brake Booster Pump Motor does not activate, replace the M9 Brake Booster Pump Motor.
|
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
Power Brake Booster Pump Replacement (LAU/A28NER)
Power Brake Booster Pump Replacement (LHU/A20NFT)
