LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2018 >> Acadia Denali, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 250 (Hydraulic Brake System) >> Diagnostic Information and Procedures >> Brake Booster Pump Motor Malfunction >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2017 Cadillac ATS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the KR14 Brake Booster Pump Motor Relay, ignition ON.
  2. Verify a test lamp illuminates between the B+ circuit terminal 30 and ground.
    • If the test lamp does not illuminate 
    1. Replace the underhood fuse block.
      • If the test lamp illuminates 
  3. Verify a test lamp illuminates between the ignition circuit terminal 86 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF, remove the test lamp.
    2. Test for less than 2 Ω in the ignition circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, verify the fuse is OK and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF, remove the test lamp.
    2. Test for infinite resistance between the ignition circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the relay.
    • If the test lamp illuminates 
  4. Connect a test lamp between the ignition circuit terminal 85 and the control circuit terminal 86.
  5. 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.
      • 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.
    • If the test lamp turns ON and OFF 
  6. 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.

    • If the test lamp does not illuminate 
  7. 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.
  8. 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.
    • If less than 10 Ω 
  9. Connect the harness connector at the M9 Brake Booster Pump Motor.
  10. Ignition ON, connect a 30 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87.
  11. 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.
    • If the M9 Brake Booster Pump Motor activates 
  12. Test or replace the KR14 Brake Booster Pump Motor Relay.
scientia non olet · About LEMON Manuals