Circuit/System Testing

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2020 GMC Yukon XL, 2020 GMC Yukon, 2020 Chevrolet Tahoe, 2020 Chevrolet Suburban, and 2020 Cadillac Escalade ESV. However, it is still accessible from the selected car via links, so may be relevant.

Ignition OFF, disconnect the harness connectors at the Q4 Vehicle Level Control Solenoid Valve and K19 Suspension Control Module, ignition ON.
Test for less than 1 V between the Q4 Vehicle Level Control Solenoid Valve circuits listed below and ground.
- Control circuit terminal C
- Control ignition circuit terminal B
- If 1 V or greater
  Repair the short to voltage on the circuit.
- Go to next step: If less than 1 V
Ignition OFF.
Test for infinite resistance between the Q4 Vehicle Level Control Solenoid Valve circuits listed below and ground.
- Control circuit terminal C
- Control circuit terminal B
- If less than infinite resistance
  Repair the short to ground on the circuit.
- Go to next step: If infinite resistance
Test for less than 2 Ω in the controls listed below end to end.
- Q4 Vehicle Level Control Solenoid Valve control circuit terminal C and K19 Suspension Control Module terminal 22.
- Q4 Vehicle Level Control Solenoid Valve control circuit terminal B and K19 Suspension Control Module terminal 41.
- If 2 Ω or greater
  Repair the open/high resistance in the circuit.
- Go to next step: If less than 2 Ω
Test or replace the Q4 Vehicle Level Control Solenoid Valve.
Verify the DTC does not set while operating the vehicle within the Conditions for Running the DTC.
- If DTC is set
  Replace the K19 Suspension Control Module.
- Go to next step: If the DTC is not set
All OK.