Circuit/System Testing

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.

Ignition OFF, disconnect the X2 harness connector at the B133 Brake Booster Fluid Flow Alarm Switch. It may take up to 2 min for all vehicle systems to power down.
Test for less than 10 Ω between the ground circuit terminal A and ground.
- If 10 Ω or greater
1. 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
Ignition OFF, disconnect the harness connector at the B19A Brake Booster Fluid Pressure Alarm Switch.
Ignition ON, test for greater than 11V between the signal circuit terminal A and ground.
- If less than 11V
  Test the signal circuit for a short to ground or an open/high resistance.
  
  If the circuit tests normal, replace the IPC.
- Go to next step: If greater than 11V
Ignition OFF, reconnect the harness connector at the B19A Brake Booster Fluid Pressure Alarm Switch and disconnect the X1 harness connector at the B133 Brake Booster Fluid Flow Alarm Switch.
Ignition ON, test for greater than 11V between the signal circuit terminal A and ground.
- If less than 11V
  Test the signal circuit for a short to ground or an open/high resistance.
  
  If the circuit tests normal, replace the B19A Brake Booster Fluid Pressure Alarm Switch
- Go to next step: If greater than 11V
Replace the B133 Brake Booster Fluid Flow Alarm.