SUT
Inflator Switch Indicator Malfunction (SUT)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions)provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
The air suspension system has the feature to utilize the air compressor as a compressed air source. When the air suspension inflator switch is activated the compressor receives a ground signal requesting compressor activation. The compressor then applies voltage to the indicator control circuit illuminating the indicator. Upon compressor activation, supplied air pressure is then diverted from the air suspension to the air supply access port.
Diagnostic Aids
The Inflator Switch Indicator Light Emitting Diode (LED) is part of the Air Suspension Inflator Switch. A complete Air Suspension Inflator Switch replacement needs to be done if the inflator switch indicator LED needs to be replaced.
Reference Information
Schematic Reference
Air Suspension Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Air Suspension Description and Operation (Description and Operation)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Scan Tool Reference
Control Module References (Programming and Relearning)for Scan Tool Information
Circuit/System Verification
Ignition ON, Observe the scan tool air suspension inflator switch indicator ASCM scan tool data while Pressing and Depressing the air suspension inflator switch. The air suspension inflator switch LED indicator should illuminate and the air compressor should activate supplying air pressure to the air accessory port.
Circuit/System Testing
1. Ignition OFF, disconnect the inflator switch LED indicator harness connector X451 terminal B1 at the automatic suspension control module (ASCM).
2. Test for less than 2.0 ohms between the inflator switch ground circuit Connector X452 terminal B and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Reconnect the inflator switch. Ignition ON, verify that a test lamp illuminates between the inflator switch LED Indicator B+ switch input circuit Connector X451 terminal B1 and ground.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the signal circuit for a short to ground.
4. Verify the scan tool Inflator Switch Indicator parameter is OFF.
• If not the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, test or replace the ASCM.
5. Install a 3A fused jumper wire between the signal circuit Connector X452 terminal A and the ASCM B+ circuit terminal Connector X451 terminal A4. Verify the scan tool Inflator Switch Indicator parameter is ON.
• If not the specified value, test the signal circuit for short to ground or open/high resistance. If the circuit tests normal, replace the ASCM.
• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ASCM.
6. If all circuits test normal, test or replace the Inflator Air Switch.
Component Testing
1. Ignition OFF, disconnect the harness at the Inflator switch.
2. Test for infinite resistance between the signal circuit Connector X452 terminal A and the B+ circuit Connector X451 terminal B1 with the switch in the open position (OFF).
• If not the specified value, replace the Inflator Air Switch.
3. Test for less than 2 ohms between the signal circuit X452 terminal A and the B+ circuit Connector X451 terminal B1 with the switch in the closed position (ON).
• If greater than the specified range, replace the Inflator Air Switch.
4. Test for infinite resistance between each terminal and the Inflator Air Switch housing/case.
• If not the specified value, replace the Inflator Air Switch.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Inflator Air Switch Replacement (SUT) (Inflator Air Switch Replacement (SUT))Inflator Air Switch Replacement (SUV) (Inflator Air Switch Replacement (SUV))
* Upon a compressor assembly replacement the Suspension Position Calibration (Suspension Position Calibration) needs to be performed.
* Compressor Assembly Automatic Level Control Air Replacement (Dual Compressors) (Compressor Assembly Automatic Level Control Air Replacement (Dual Compressors))