Suspension Control System - Automatic Level Control (Ascm) Cadillac DTS I

Fastener Tightening Specifications

Scheme 1

DIAGNOSTIC CODE INDEX

DIAGNOSTIC CODE INDEX

Diagnostic Starting Point - Air Suspension

Begin the system diagnosis with the Diagnostic System Check - Vehicle . The Diagnostic System Check - Vehicle will provide the following information

1. The identification of the control modules which command the system
2. The ability of the control modules to communicate through the serial data circuit
3. The identification of any stored diagnostic trouble codes (DTCs) and their status

The use of the Diagnostic System Check - Vehicle will identify the correct procedure for diagnosing the system and where the procedure is located.

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit/System Description

The left and right rear air suspension position sensors provide a signal voltage between 0.5-4.75 volts to the air suspension control module. This signal voltage represents the wheel's position relative to the body. The air suspension control module provides a 5-volt reference and a low reference to the sensors.

Conditions for Running the DTC

1. Ignition voltage is between 9-16 volts.
2. Vehicle is in motion.

Conditions for Setting the DTC

1. The air suspension module detects the voltage at the strut position sensor signal circuit is less than 0.5 volt or greater than 4.75 volts for more than 500 milliseconds.
2. The air suspension module detects that there is a wide differential between the signal voltage ranges of one sensor in comparison to the other over a predetermined period of time.

Action Taken When the DTC Sets

1. Air suspension functionality is suspended.
2. The SERVICE SUSPENSION SYSTEM message is displayed.

Conditions for Clearing the DTC

The condition for setting the DTC no longer exists.

Reference Information

Schematic Reference

Air Suspension Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Air Suspension Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool RR Position Sensor and LR Position Sensor parameters. The parameters should be between 0.5-4.75 volts.

Circuit/System Testing

1. Ignition OFF, remove the ELC MDL Fuse in the rear fuse block and disconnect the harness connector at the appropriate position sensor.
2. Test for less than 2.0 ohms between low reference circuit terminal 3 (LR) or terminal 1 (RR) and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the air suspension control module.
3. Install the ELC MDL Fuse in the rear fuse block.
4. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 1 (LR) or terminal 3 (RR) and ground. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the air suspension control module. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the air suspension control module.
5. Verify the appropriate scan tool Position Sensor parameter is less than 0.5 volts. If greater than the specified range, test the signal circuit terminal 2 for a short to voltage. If the circuit tests normal, replace the air suspension control module.
6. Install a 3A fused jumper wire between the signal circuit terminal 2 and the 5-volt reference circuit terminal 1 (LR) or terminal 3 (RR). Verify the appropriate scan tool Position Sensor parameter is greater than 4.8 volts. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the air suspension control module.
7. If all circuits test normal, test or replace the rear suspension position sensor.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Air Spring Leveling Sensor Replacement»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm)
2. «Suspension Position Calibration»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm__suspension-position-calibration)
3. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for air suspension control module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit Description

The air suspension control module (ASCM) controls the compressor relay and exhaust valve ground to maintain the height of the vehicle based on voltage signals from the rear height sensors. The ASCM raises and lowers the vehicle in order to keep the vehicle level.

Battery voltage is between 9-16 volts.

1. The exhaust valve control circuit is shorted to voltage, ground, or open when solenoid activation is commanded ON for 2.5 seconds.
2. The exhaust valve B+ circuit is shorted to ground or open when solenoid activation is commanded ON for 5 seconds.
3. Any component voltage supply circuit from the air suspension control module that is shorted to ground.
4. Any suspension position sensor low reference circuit that is shorted to voltage.

1. The air suspension system will be inoperative.
2. The DIC will display SERVICE SUSPENSION SYS.

Conditions for Clearing the MIL/DTC

1. DTC C0660 will change from a current DTC to a history DTC on the next ignition cycle.
2. DTC C0660 will be cleared from history after 50 ignition cycles.

Schematic Reference

Air Suspension Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Air Suspension Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, command the air suspension exhaust solenoid valve ON and OFF with the scan tool. The exhaust solenoid valve should turn ON and OFF with each command.

1. Ignition OFF, disconnect the harness connector at the air suspension compressor exhaust solenoid.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal and ground. If the test lamp does not illuminate, test for the following conditions listed below. If all circuits test normal, replace the air suspension compressor assembly. An open, short to ground, or short to voltage in the air suspension exhaust valve solenoid control circuit A short to ground in one of the B+ or 5-volt reference circuits from the air suspension control module A short to voltage in one of the position sensor low reference circuits
3. Connect a test lamp between the B+ circuit terminal and the control circuit terminal.
4. Command the exhaust solenoid ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the air suspension control module. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the air suspension control module.
5. If all circuits test normal, replace the air suspension compressor assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Air Spring Compressor Replacement»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm)
2. «Suspension Position Calibration»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm__suspension-position-calibration)
3. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for air suspension control module replacement, setup and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The air suspension adjusts the vehicle suspension ride height. The air suspension control module (ASCM) determines the height of the vehicle based on the signal from the rear height sensors which are supplied a 5-volt reference voltage from the module. The ASCM raises and lowers the vehicle in order to keep the vehicle level.

Battery voltage is between 9-16 volts.

The air suspension module detects that the supplied 5-volt reference voltage circuit for both suspension position sensors falls below 4.75 volts or exceeds 5.25 volts.

1. The air suspension system will be inoperative.
2. The SERVICE SUSPENSION SYSTEM message will be displayed.

1. When the fault is no longer present, DTC C0696 will change from a current DTC to a history DTC on the next ignition cycle.
2. DTC C0696 will be cleared from history after 50 ignition cycles.

Schematic Reference

Air Suspension Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Air Suspension Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect both suspension position sensors.
2. Test for less than 2.0 ohms between suspension position sensor low reference terminal 3 (LR) and terminal 1 (RR) and ground. If greater than the specified range, test the low reference circuit for an open or high resistance. If all circuits test normal, replace the air suspension control module.
3. Ignition ON, test for 4.8-5.2 volts between the sensor 5-volt reference circuit terminal 1 (LR) and terminal 3 (RR) of the harness connectors and ground. If less that the specified range, test the 5-volt reference circuit for open/high resistance or a short to ground. If the circuit tests normal, replace the air suspension control module. If greater that the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the air suspension control module.
4. Ignition OFF, reconnect the LR suspension position sensor.
5. Ignition ON, test for 4.75-5.25 volts exists between the RR position sensor 5-volt reference circuit terminal 3 and ground. If less than the specified range, test or replace the LR suspension position sensor.
6. Test or replace RR suspension position sensor that is not connected.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Air Spring Leveling Sensor Replacement»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm)
2. «Suspension Position Calibration»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm__suspension-position-calibration)
3. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for air suspension control module replacement, setup and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The air suspension control module monitors the run time of the compressor. If the compressor has run for more than 1 hour during an ignition cycle, the air suspension control module switches OFF the compressor relay. The run timer counts down when the compressor is OFF with the ignition ON.

Battery voltage is between 9-16 volts.

The air suspension compressor has continuously run for more than 1 hour during the same ignition cycle.

1. The air suspension system will be inoperative.
2. The SERVICE SUSPENSION SYSTEM message will be displayed.

1. When the fault is no longer present, DTC C0707 will change from a current DTC to a history DTC on the next ignition cycle.
2. DTC C0770 will be cleared from history after 50 ignition cycles.

Schematic Reference

Air Suspension Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Air Suspension Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, command the air suspension compressor ON and OFF with the scan tool output control. The compressor should turn ON and OFF with each command.

1. Verify that there are no air leaks in the system. If a leak is found, repair or replace the leaking component as necessary.
2. Remove the ELC CMPRSR relay from the rear fuse block. Verify that the compressor runs continuously. If the compressor does not run continuously, test or replace the relay.
3. Ignition ON, verify that a test lamp does not illuminate between the compressor B+ terminal of the relay connector and ground. If the test lamp illuminates, test the B+ circuit for a short to voltage. If the circuits test normal, replace the air suspension control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Air Spring Replacement»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm)
2. «Air Suspension Air Line Replacement»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm)
3. «Air Spring Compressor Replacement»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm)
4. «Suspension Position Calibration»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm__suspension-position-calibration)
5. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for air suspension control module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The air suspension pressure sensor sends a voltage signal to the air suspension control module that corresponds to a pressure within the range of 30-180 psi. The air suspension control module also uses this signal to verify that the proper amount of pressure is achieved in the air dryer within 23 seconds prior to opening of the inlet valves for inflation of the air springs.

Battery voltage is between 9-16 volts.

1. The air suspension module detects that the supplied 5-volt reference voltage circuit for the pressure sensor falls below 4.75 volts or exceeds 5.25 volts.
2. The air suspension module detects that the signal voltage circuit for the pressure sensor falls below 0.5 volt or exceeds 4.75 volts.

1. The air suspension system will be inoperative.
2. The SERVICE SUSPENSION SYSTEM message will be displayed.

1. When the fault is no longer present, DTC C0711 will change from a current DTC to a history DTC on the next ignition cycle.
2. DTC C0711 will be cleared from history after 50 ignition cycles.

Schematic Reference

Air Suspension Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Air Suspension Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, observe the scan tool Air Pressure Sensor parameter. The parameter should be between 0.5-4.75 volts.

1. Verify that there are no air leaks in the system. If a leak is found, repair or replace the leaking component as necessary.
2. Ignition OFF, remove the ELC MDL fuse in the rear fuse block and disconnect the harness connector at the air pressure sensor.
3. Test for less than 2.0 ohms between the low reference terminal at the harness connector and ground. If greater than specified, test the low reference circuit for open/high resistance. If the circuit tests normal, replace the air suspension control module.
4. Ignition ON, verify that 4.8-5.2 volts exists between the 5-volt reference circuit terminal of the harness connector and ground. If less than the specified range, test the 5-volt reference circuit for open/high resistance or a short to ground. If the circuit tests normal, replace the air suspension control module. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the air suspension control module.
5. Verify the scan tool Air Pressure Sensor parameter is less than 0.5 volt. If greater than the specified range, test the signal circuit terminal for a short to voltage. If the circuit tests normal, replace the air suspension control module.
6. Install a 3A fused jumper wire between the signal circuit terminal and the 5-volt reference circuit terminal. Verify the scan tool Air Pressure Sensor parameter is greater than 4.8 volts. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the air suspension control module.
7. If all circuits test normal, test or replace the air pressure sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Air Spring Replacement»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm)
2. «Air Suspension Air Line Replacement»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm)
3. «Air Spring Compressor Replacement»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm)
4. «Suspension Position Calibration»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm__suspension-position-calibration)
5. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for air suspension control module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The air suspension control module (ASCM) adjusts the vehicle suspension ride height. The ASCM determines the height of the vehicle based on the voltage from the suspension position sensors. The module grounds the ELC COMP relay and the exhaust control solenoid to raise and lower the vehicle in order to keep the vehicle level.

1. The ASCM is powered up.
2. The ASCM is commanding the compressor ON.

1. The leveling compressor relay coil control circuit is shorted to voltage, ground, or open for 5 seconds.
2. The leveling compressor relay coil B+ circuit is shorted to ground or open for 5 seconds.

The air suspension will be inoperative.

The ASCM does not detect a failure during the self test.

Diagnostic Aids

This circuit is monitored during every functional operation of the compressor relay output and every 3.3 milliseconds when output is active. If a compressor relay fault is detected, the ASCM retries the output every 15 seconds to try to recover from the fault.

Schematic Reference

Air Suspension Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Air Suspension Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, command the compressor relay ON with a scan tool. Listen for the operation of the ELC CMPRSR relay and the air suspension compressor.

1. Ignition OFF, remove the ELC CMPRSR relay.
2. Ignition ON, verify that a test lamp does not illuminate between the rear fuse block relay control circuit terminal 11 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
3. Verify that a test lamp illuminates between the rear fuse block B+ circuit terminal 15 and ground. If the test lamp does not illuminate, test the relay B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the air suspension control module.
4. Connect a test lamp between the B+ circuit terminal 15 and the control circuit terminal 11.
5. Command the compressor relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the air suspension control module. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the air suspension control module.
6. If all circuits test normal, test or replace the ELC CMPRSR relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Relay Replacement (Attached to Wire Harness)»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-introduction) or «Relay Replacement (Within an Electrical Center)»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-introduction)
2. «Suspension Position Calibration»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm__suspension-position-calibration)
3. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for air suspension control module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The air suspension control module monitors the run time and temperature of the compressor. If the compressor has run excessively and/or the operating temperature increases above the normal limits, the air suspension control module switches OFF the compressor relay.

Battery voltage is between 9-16 volts.

The air suspension control module detects a compressor overheating condition during air suspension compressor operation.

1. The air suspension system will be inoperative.
2. The SERVICE SUSPENSION SYSTEM message will be displayed.

1. When the fault is no longer present, DTC C0713 will change from a current DTC to a history DTC on the next ignition cycle.
2. DTC C0713 will be cleared from history after 50 ignition cycles.

Schematic Reference

Air Suspension Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Air Suspension Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Verify that there are no air leaks in the system. If a leak is found, repair or replace the leaking component as necessary.
2. Ignition ON, verify that the air suspension compressor is not mechanically binding. If a mechanical condition is found, replace the air suspension compressor.
3. Observe the scan tool Compressor Temperature parameter, the parameter should display OK. If not the specified value, test or replace the air suspension compressor.
4. Clear the DTC with the scan tool and run the air suspension compressor with the scan tool output control. The DTC should not reset. If DTC C0713 resets, replace the air suspension control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Air Spring Replacement»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm)
2. «Air Suspension Air Line Replacement»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm)
3. «Air Spring Compressor Replacement»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm)
4. «Suspension Position Calibration»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm__suspension-position-calibration)
5. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for air suspension control module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The air suspension adjusts the vehicle suspension ride height. The air suspension control module (ASCM) controls the left rear and right rear air pressure control valves based on input from the position sensors to keep the vehicle level from front to back and side to side.

1. Battery voltage is between 9-16 volts.
2. The valve solenoid is commanded ON.

1. The pressure control valve solenoid control circuit is shorted to voltage, ground, or open when solenoid activation is attempted 4 times.
2. The pressure control valve solenoid B+ circuit is shorted to voltage, ground, or open when solenoid activation is attempted 4 times.

1. The air suspension system will be inoperative.
2. The SERVICE SUSPENSION SYSTEM message will be displayed.

1. When the fault is no longer present, DTC C0716 and C0717 will change from a current DTC to a history DTC on the next ignition cycle.
2. DTC C0716 and C0717 will be cleared from history after 50 ignition cycles.

Schematic Reference

Air Suspension Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Air Suspension Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, command the air suspension LR/RR Control Valve Command ON and OFF with a scan tool. Verify the control valve solenoids turn ON and OFF with each command.

1. Ignition OFF, disconnect the appropriate air suspension control valve solenoid.
2. Ignition ON, verify that a test lamp does not illuminate between the solenoid control circuit terminal at the connector and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
3. Verify that a test lamp illuminates between the B+ circuit terminal 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, test or replace the air suspension compressor assembly.
4. Connect a test lamp between the B+ circuit terminal and the control circuit terminal.
5. Command the appropriate control valve ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the air suspension control module. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the air suspension control module.
6. If all circuits test normal, replace the air suspension compressor assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Air Spring Compressor Replacement»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm)
2. «Suspension Position Calibration»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm__suspension-position-calibration)
3. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for air suspension control module replacement, setup and programming

Symptoms - Air Suspension

Review the system operation in order to familiarize yourself with the system functions. Refer to Air Suspension Description and Operation .

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the air suspension. Refer to «Checking Aftermarket Accessories»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__checking-aftermarket-accessories) .
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
3. Inspect for binding or damaged air springs.

Intermittent

Electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Symptom

Refer to the Air Suspension Malfunction diagnostic procedure in order to diagnose the symptom.

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The air suspension system uses level sensors, a control module, compressor, pressure sensor, right and left pressure valves, and exhaust valve to increase or decrease air pressure in the system to control trim height. The air suspension control module supplies battery voltage to the exhaust valve, pressure valves, and compressor relay. The air suspension control module also controls the ground circuits that activate the exhaust valve, pressure valves, and compressor relay which maintain trim height based on the level sensor input voltage.

1. If the compressor runs continuously, inspect the system for any leaks or damaged components.
2. Performing the «Suspension Position Calibration»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm__suspension-position-calibration) procedure may correct the condition.

Schematic Reference

Automatic Level Control Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Automatic Level Control Description and Operation (With F55) or Automatic Level Control Description and Operation (W/O F55)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, command the Compressor Relay ON and OFF with a scan tool. Verify that the compressor turns ON and OFF with each command. If the compressor does not operate or operates continuously, refer to «Compressor Malfunction»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm) .
2. Ignition ON, command the exhaust valve ON and OFF with a scan tool. Verify the exhaust valve clicks and the vehicle height changes with each command. If the exhaust valve does not click or the vehicle height does not change, refer to «Exhaust Valve Malfunction»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm) .
3. Ignition ON, command the LR and RR Control Valves ON and OFF with a scan tool. Verify the control valves click and the vehicle applicable rear corner height changes with each command. If a control valve does not click or the applicable rear corner height does not change, refer to «Control Valve Malfunction»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm) .

Compressor Malfunction

1. Ignition OFF, disconnect the harness connector at the leveling compressor.
2. Test for less than 1 ohm between the compressor ground circuit terminal and ground. If greater than the specified range, test the ground circuit for an open/high resistance. If the circuit tests normal, test or replace the air compressor assembly.
3. Connect the test lamp between the control circuit terminal and ground.
4. Ignition ON, command the compressor relay ON and OFF with the scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ELC MDL fuse is open, test or replace the ALC compressor assembly. If the circuit tests normal and the ELC MDL fuse is not open, test or replace the ELC compressor relay. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, test or replace the ELC compressor relay.
5. Test or replace the air compressor.

Exhaust Valve Malfunction

1. Ignition OFF, connect a test lamp between the exhaust valve connector control circuit terminal and the B+ circuit terminal.
2. Ignition ON, command the exhaust valve ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the air suspension control module. If the test lamp is always OFF, test the control circuit for an open/high resistance. If the circuit tests normal, replace the air suspension control module.
3. If all circuits test normal, test or replace the air suspension compressor assembly.

Control Valve Malfunction

1. Ignition OFF, connect a test lamp between the affected control valve connector control circuit terminal and the B+ circuit terminal.
2. Ignition ON, command the affected control valve ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the air suspension control module. If the test lamp is always OFF, test the control circuit for an open/high resistance. If the circuit tests normal, replace the air suspension control module.
3. If all circuits test normal, test or replace the air suspension compressor assembly.

Component Testing

1. Ignition OFF, disconnect the relay.
2. Test for 50-200 ohms between terminals 85 and 86. If not the specified value, replace the relay.
3. Test for infinite resistance between the following terminals: 30 and 86 30 and 87 30 and 85 85 and 87 If the resistance is not within the specified range, replace the relay.
4. Install a 20A fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2.0 ohms between terminals 30 and 87. If greater than the specified range, replace the relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Suspension Position Calibration»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm__suspension-position-calibration)
2. «Air Spring Compressor Replacement»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm)
3. «Compressor Assembly Automatic Level Control Air Replacement»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm)
4. «Air Spring Replacement»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm)
5. «Air Suspension Air Line Replacement»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm)
6. «Relay Replacement (Attached to Wire Harness)»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-introduction) or «Relay Replacement (Within an Electrical Center)»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-introduction)
7. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for air suspension control module replacement, setup and programming

Suspension Position Calibration

After air suspension control module (ASCM), or suspension position sensor replacement, or if the vehicle exhibits an uneven rear suspension position, the following calibration procedure must be performed.

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Using 2 adjustable lifting devices, support the rear of the vehicle at the lifting points forward of the rear wheel arches.
4. Depressurize the air suspension system, allowing the weight of the vehicle to rest on the lifting devices. Refer to «Air Suspension Depressurization»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm__air-suspension-depressurization) .
5. Measuring from the wheel center to the wheel arch, ensure a 46 cm (18.1 in) distance between the 2 points for both left and right sides. Adjust the lifting devices as needed.
6. With the scan tool select Suspension, and then Air Suspension.
7. Select Special Functions, Air Suspension Control Module.
8. Select Suspension Position Calibration and press the Set key.
9. Remove the lifting devices.
10. Cycle the ignition OFF, then start the engine and allow to run for 1 minute. Verify the air suspension system is functioning properly.
11. If additional adjustments are required for slight variation in the trim height after completing the Suspension Position Calibration, use the Suspension Calibration Adjustment procedure under Special Functions and follow the Tech2 on-screen instructions to adjust each rear wheel to the correct trim height. The Suspension Calibration Adjustment will increase or decrease the left and/or right rear wheel center to wheel arch measurement from 0.64 cm (0.25 in) to as much as 2.54 cm (1 in) to correct the variation in the trim height.

Air Suspension Depressurization

To depressurize the Air Suspension System, install the scan tool with key in the ON position. Go to the special functions menu of the air suspension section and follow the on screen directions. The suspension will deflate the air springs until the suspension is on the jounce bumpers.

Air Suspension Pressurization

1. While the vehicle is raised, ensure that the lower end of the air springs are completely engaged in the spring supports on the lower control arm.
2. Lower the vehicle but do not allow the vehicles tires to contact the ground.
3. Turn the ignition ON, with the engine OFF.
4. Install a scan tool.
5. With the scan tool in hand, raise the vehicle.
6. With the scan tool select Special Functions.
7. Select Pressurize System.
8. Press the ON soft key and visually observe the springs as their air pressures inflate.
9. When the air spring inflation pressures have reached a pressure where there are no visible wrinkles, or folds in the air springs, press the OFF soft key. This function will also stop after 40 seconds.
10. Press the Exit key.
11. Lower the vehicle.
12. Cycle the ignition OFF, then back ON, with the engine ON to allow the air suspension system to regain the desired rear suspension position.

Removal Procedure

1. Remove the compressor assembly from the vehicle and place on a bench. Refer to «Compressor Assembly Automatic Level Control Air Replacement»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm) .
2. Disconnect the electrical connector (1).
3. Release the control module upper and lower tabs.
4. remove the control module (2) from the bracket.

Installation Procedure

1. Install the control module (2) to the bracket. Ensure the upper and lower locking tabs are engaged.
2. Connect the electrical connector (1).
3. Install the compressor assembly to the vehicle. Refer to «Compressor Assembly Automatic Level Control Air Replacement»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm) .
4. Perform the suspension position calibration procedure. Refer to «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for replacement and setup information.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/dts/i-2005-2011/remont/hoistjack/#general-information__lifting-jacking-the-vehicle) .
2. Remove the rear wheel and tire. Refer to «Tire and Wheel Removal and Installation»(/cadillac/dts/i-2005-2011/remont/wheel-tire-system/#tires-and-wheels__tire-wheel-removal-installation) .
3. Support the rear suspension at the proper D trim height. Refer to «Trim Height Specifications»(/cadillac/dts/i-2005-2011/remont/suspension-front/#suspension-general-diagnosis__trim-height-specifications) .
4. Disconnect the air spring leveling sensor arm from the trailing arm.
5. Disconnect the air spring leveling sensor electrical connector.
6. Remove the air spring leveling sensor nut and remove the sensor.

1. Position the air spring leveling sensor and install the nut. Tighten: Tighten the air spring leveling sensor nut to 9 N.m (80 lb in).
2. Connect the air spring leveling sensor electrical connector.
3. Connect the air spring leveling sensor to the trailing arm.
4. Remove the rear suspension support.
5. Install the rear wheel and tire. Refer to «Tire and Wheel Removal and Installation»(/cadillac/dts/i-2005-2011/remont/wheel-tire-system/#tires-and-wheels__tire-wheel-removal-installation) .
6. Lower the vehicle.
7. Perform the suspension position calibration procedure. Refer to «Suspension Position Calibration»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm__suspension-position-calibration) .

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/dts/i-2005-2011/remont/hoistjack/#general-information__lifting-jacking-the-vehicle) .
2. Depressurize the air suspension system. Refer to «Air Suspension Depressurization»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm__air-suspension-depressurization) .
3. Remove the air compressor assembly. Refer to «Compressor Assembly Automatic Level Control Air Replacement»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm) .
4. Disconnect the air hose (1) from the air dryer.
5. Remove the air compressor nuts and washers (3).
6. Remove the air compressor with the dryer (2) from the bracket.

1. Install the air compressor with the dryer (2) to the bracket.
2. Install the air compressor nuts and washers (3). Tighten: Tighten the nuts to 2 N.m (18 lb in).
3. Connect the air hose (1) to the air dryer. Ensure the air hose is fully seated into the air dryer.
4. Install the air compressor assembly. Refer to «Compressor Assembly Automatic Level Control Air Replacement»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm) .
5. Pressurize the air suspension system after the repair has been completed. Refer to «Air Suspension Pressurization»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm__air-suspension-pressurization) .
6. Lower the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/dts/i-2005-2011/remont/hoistjack/#general-information__lifting-jacking-the-vehicle) .

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/dts/i-2005-2011/remont/hoistjack/#general-information__lifting-jacking-the-vehicle) .
2. Depressurize the air suspension system. Refer to «Air Suspension Depressurization»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm__air-suspension-depressurization) .
3. Disconnect the right and left air tubes (1) from the control solenoids.
4. Disconnect the electrical connectors (1) from the compressor assembly.
5. Remove the air intake filter (1) from the frame.
6. Remove the air compressor assembly nuts (1).
7. Remove the air compressor assembly bolts (2).
8. Remove the air compressor assembly (1) from the vehicle.

1. Position the air compressor assembly (1) to the vehicle.
2. Install the air compressor assembly nuts (1) and bolts (2) to the vehicle. Tighten: Tighten the nuts and bolts to 9 N.m (80 lb in).
3. Install the air compressor filter (1) to the frame.
4. Connect the air compressor electrical connectors (1).
5. Connect the right and left air tubes (1) to the control solenoids.
6. Pressurize the air suspension system after the repair has been completed. Refer to «Air Suspension Pressurization»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm__air-suspension-pressurization) .
7. Lower the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/dts/i-2005-2011/remont/hoistjack/#general-information__lifting-jacking-the-vehicle) .

Scheme 2

1. Depressurize the air suspension system. Refer to «Air Suspension Depressurization»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm__air-suspension-depressurization) .
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/dts/i-2005-2011/remont/hoistjack/#general-information__lifting-jacking-the-vehicle) .
3. Disconnect all air lines using the following procedure. Air spring connection shown. All others are similar. Push the air supply line into the air spring connection and hold in place. Depress and hold the air supply line collet (2) down. Remove the air supply line (1) from the air spring.

1. Install air line to the appropriate fitting until the line bottoms.
2. Pressurize the air springs. Refer to «Air Suspension Pressurization»(/cadillac/dts/i-2005-2011/remont/electronic-suspension/#suspension-control-system-automatic-level-control-ascm__air-suspension-pressurization) .
3. Lower vehicle.
4. Start the vehicle and run for approximately 2 minutes to verify that the air suspension system is functioning properly.

Air Suspension

The air suspension system fully suspends the rear of the vehicle and maintains a desired rear suspension position during all types of hauling and loading conditions. The primary mission of the air suspension system is the following for the rear suspension under loaded and unloaded conditions

1. Keep vehicle visually level.
2. Maintain optimal ride height.

The air suspension system consists of the following items

1. Air lines
2. Air suspension control module (ASCM)
3. Air springs
4. Air suspension compressor sensor
5. Air suspension compressor relay
6. LR and RR suspension position sensor
7. Serial data circuits with data exchange to the engine control module (ECM) and body control module (BCM)

Air Suspension Description

When the vehicle is unloaded, the rear suspension is at a desired position, which is monitored by the ASCM using its LR and RR position sensor signal voltage inputs. As weight is added to the rear of the vehicle, the rear suspension position changes thus changing the position sensor's signal voltage inputs. If the ASCM detects a steady constant change in position sensor signal voltage for at least 3 seconds, it responds by commanding on the compressor relay causing the air compressor to activate. Once the air compressor is activated, the ACSM opens the LR and RR air spring control valves, causing the rear air spring pressures to inflate. This inflation raises the rear of the vehicle to regain the desired suspension position. When weight is removed from the rear of the vehicle, the ASCM responds by commanding ON the exhaust valve and LR and RR air spring control valves, causing the air spring pressures to deflate. This deflation lowers the rear of the vehicle to regain the desired suspension position. The ASCM also monitors the engine run status from the ECM via the serial data circuit and will not allow compressor activity unless the engine is running to avoid battery run down.

Air Compressor

The compressor is a positive displacement air pump driven by a 12-volt DC permanent magnet motor. The compressor draws filtered air through an intake line attached to the chassis rail which is then run through a dryer containing a moisture-absorbing chemical that dries the air before it is sent to the air springs. The moisture is removed from the dryer during exhaust events, or when the system is depressurized. If the compressor is exposed to high thermal conditions due to excessive run time, the ASCM will command the compressor relay OFF to protect the compressors from thermal damage

Electronically Controlled Air Suspension Relay

The air compressor is controlled by the air suspension control module by the use of a relay. The relay and wiring are protected with a 60-amp fuse. The air suspension control module will only activate the compressor relay when the engine is running.

Air Suspension Control Module

The air suspension control module (ASCM) has the ability to detect malfunctions within the air suspension system. Any malfunction detected will cause the driver information center (DIC) to display the SERVICE SUSPENSION SYSTEM message.

Rear Air Springs

The air springs are mounted in the frame in the same location were the coil spring is mounted for a vehicle without air suspension. Support pieces are affixed to the control arm for the air springs.

Special Tools

Illustration Tool Number/ Description J 24319-B Steering Linkage and Tie Rod Puller

Scheme 3

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Component Connector End Views
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Diagnostic Repair Verification
• Relay Replacement (Attached to Wire Harness)
• Checking Aftermarket Accessories
• Automatic Level Control Schematics
• Automatic Level Control Description and Operation (With F55)
• Lifting and Jacking the Vehicle
• Tire and Wheel Removal and Installation
• Trim Height Specifications
• Fastener Notice
• DTC C0625 or C0630
• Suspension Position Calibration
• Air Suspension Depressurization
• Air Suspension Pressurization
• Fastener Tightening Specifications