Pinpoint Test H: The Air Suspension System Is Inoperative Without DTCs and With The Vehicle At Rest
Vehicle Dynamic Suspension
Pinpoint Tests
Pinpoint Test H: The Air Suspension System is Inoperative Without DTCs and with the Vehicle at Rest
Normal Operation
The scan tool is used to communicate with the Vehicle Dynamics Module (VDM) and run the self-test. The VDM is supplied fused battery voltage through Battery Junction Box (BJB) fuse 48 (30A) along circuit SBB48 (VT/RD), and fused ignition circuit through BJB fuse 53 (10A) along circuit CBB53 (GY/BN). A ground path is provided for the module along circuit GD120 (BK/GN). The VDM communicates with the other modules along the High Speed Controller Area Network (HS-CAN). The VDM must receive inputs from several different components before it will allow the vehicle dynamic suspension system to operate.
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- Door switch is indicating door ajar status
- Vehicle speed signal
- System is not enabled
- VDM
PINPOINT TEST H: THE AIR SUSPENSION SYSTEM IS INOPERATIVE WITHOUT DTCs AND WITH THE VEHICLE AT REST
NOTE: If the vehicle has been sitting with the key in the run position, it may be necessary to open and close the driver side door. This will enable the system to carry out the pump or vent functions quicker.
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H1 VERIFY THAT THE SYSTEM IS ENABLED
- Verify that the air suspension system is enabled. Refer to Air Suspension System Disable/Enable Air Suspension System Disable/Enable.
- Is the air suspension system enabled?
Yes
GO to H2.
No
ENABLE the air suspension system. REFER to Air Suspension System Disable/Enable Air Suspension System Disable/Enable.
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H2 CHECK THE VDM IGNITION SWITCH (IGN_RUN) PID
- Connect the scan tool.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: DataLogger VDM.
- While cycling the ignition key from ON to OFF and then back to ON, monitor the IGN_RUN PID.
- Does the PID display NO with the key in the OFF position and YES with the key in the ON position?
Yes
GO to H3.
No
VERIFY BJB fuse 53 (10A) is OK. If OK, REPAIR circuit CBB65 (WH/OG). If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. TEST the system for normal operation. Diagrams By Number
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H3 CHECK THE VDM DRIVER DOOR AJAR SWITCH (D_DR_SW) PID
- Ignition ON.
- Monitor VDM door ajar PID.
- Close all the doors, liftgate, liftgate glass and power running boards.
- While monitoring the D_DR_SW PID, open and close the driver door.
- Does the PID change from CLOSED to OPEN?
Yes
GO to H4.
No
REFER to Module Configuration Testing and Inspection to diagnose the High Speed Controller Area Network (HS-CAN) concern.
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H4 CHECK THE VDM VSS PID
- Monitor the VSS PID.
- Test drive the vehicle at different speeds.
- Does the VSS PID match the speedometer within 8 km/h (5 mph)?
Yes
GO to H5.
No
REFER to Module Configuration Testing and Inspection to diagnose the HS-CAN concern.
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H5 CHECK THE VDM CONNECTORS
- Ignition OFF.
- Disconnect: VDM C2131a.
- Disconnect: VDM C2131b.
- Check the VDM connectors for:
- corrosion.
- pushed-out pins.
- spread terminals.
- Connect: VDM C2131a.
- Connect: VDM C2131b.
- Make sure the connectors are seated correctly then enable the air suspension system, operate the system and verify the concern is still present.
- Is the concern still present?
Yes
GO to H6.
No
The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector.
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H6 VERIFY THE SYSTEMS OPERATION
- Using the scan tool, carry out the Pneumatic Test. Inspection and Verification
- Does running the Pneumatic Test generate any DTCs?
Yes
RECORD the DTCs and REFER to the Vehicle Dynamics Module (VDM) DTC Chart. Diagnostic Trouble Code Tests and Associated Procedures
No
The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector.
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