Circuit/System Testing

Ignition OFF, disconnect the KR14 Brake Booster Pump Motor Relay, ignition ON.
Verify a test lamp illuminates between the following B+ circuits and ground.
- B+ circuit terminal 30
- B+ circuit terminal 85
- If the test lamp does not illuminate
  Refer to Power Mode Mismatch (Without KL9) , or Power Mode Mismatch (With KL9) .
- Go to next step: If the test lamp illuminates
Connect a test lamp between the ignition circuit terminal 85 and the control circuit terminal 86.
Verify the test lamp turns ON and OFF when commanding the Brake Booster Pump Motor On and Off with a scan tool.
- If the test lamp is always OFF
1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K17 Electronic Brake Control Module, ignition ON.
2. Test for less than 1 V between the control circuit and ground.
  - If 1 V or greater, repair the short to voltage on the circuit.
  - Go to next step: If less than 1 V
3. Ignition OFF.
4. Test for less than 2 Ω in the control circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, replace the K17 Electronic Brake Control Module.
- If the test lamp is always ON
1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K17 Electronic Brake Control Module.
2. Test for infinite resistance between the control circuit and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - If infinite resistance, replace the K17 Electronic Brake Control Module.
- Go to next step: If the test lamp turns ON and OFF
Verify a test lamp does not illuminate between the control circuit terminal 87 and ground.
- If the test lamp illuminates
  Repair the short to voltage on the circuit.
- Go to next step: If the test lamp does not illuminate
Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the M9 Brake Booster Pump Motor. It may take up to 2 min for all vehicle systems to power down.
Test for less than 10 Ω between the M9 Brake Booster Pump Motor ground circuit terminal 2 and ground.
- If 10 Ω or greater
1. Ignition OFF.
2. Test for less than 2 Ω in the ground circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, repair the open/high resistance in the ground connection.
- Go to next step: If less than 10 Ω
Connect the harness connector at the M9 Brake Booster Pump Motor.
Ignition ON, connect a 30 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87.
Verify the M9 Brake Booster Pump Motor is activated.
- If the M9 Brake Booster Pump Motor does not activate and the circuit fuse is good
1. Ignition OFF, remove the jumper wire.
2. Test for less than 2 Ω in the control circuit terminal 87 end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, test or replace the M9 Brake Booster Pump Motor.
- If the M9 Brake Booster Pump Motor does not activate and the circuit fuse is open
1. Ignition OFF, remove the jumper wire.
2. Test for infinite resistance between the control circuit and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - If infinite resistance, replace the brake booster pump motor.
- Go to next step: If the M9 Brake Booster Pump Motor activates
Test or replace the KR14 Brake Booster Pump Motor Relay.