Suspension Control System - Suspension Leveling Cadillac Escalade GMT800

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Diagnostic Starting Point-Electronic Suspension Control

Begin the system diagnosis with the DIAGNOSTIC SYSTEM CHECK-ELECTRONIC SUSPENSION CONTROL . You may want to review the ELECTRONIC SUSPENSION CONTROL DESCRIPTION AND OPERATION before beginning the diagnosis. The Diagnostic System Check 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 will identify the correct procedure for diagnosing the system and where the procedure is located.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

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1. 2. Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
2. 3. The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.
3. 4. Check for the presence of DTCs.
4. 5. Check for the presence of DTCs.

Scan Tool Output Controls

Use the scan tool Special Functions in order to perform certain tests and functions in the electronic suspension control (ESC) system and the automatic level control (ALC) system. The SERVICE RIDE CONTROL message can also be turned On and Off in the message center in the I/P. The table below lists the tests and functions that are available for the ESC system. The tests and functions are listed in alphabetical order.

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Scan Tool Data List

The electronic suspension control (ESC) scan tool data list contains all the electronic suspension control system related parameters that are available on the scan tool. The parameters in the list are arranged in alphabetical order. The column, Data List, indicates the location of the parameter within the scan tool menu selections.

Use the ESC scan tool data list as directed by a diagnostic table or in order to supplement the diagnostic procedures. Begin all of the diagnostic procedures with the Diagnostic System Check. Use the ESC scan tool data list only after the following is determined

1. The ESC Diagnostic System Check is complete.
2. The on board diagnostics are operating correctly.
3. No diagnostic trouble codes (DTCs) are displayed.

The typical scan tool data values are an average of the displayed values recorded from normally operating vehicles. The typical scan tool data values are intended to represent what a normally functioning system would display with certain preliminary settings. The values you get may vary slightly due to a low battery charge or other reasons. But the values should be very close.

Use only the parameters listed in the tables for diagnosis. If a scan tool reads other parameters, the values are not recommended for use in diagnosis.

Refer to SCAN TOOL DATA DEFINITIONS for further detailed information.

Data Display

The scan tool's input display function can be helpful in determining if the electronic suspension control (ESC) module is receiving the correct input status. This can assist in determining if the ESC system is actually commanding a suspension damper solenoid.

Cycle Outputs

A scan tool may be used in order to command the suspension damper solenoids and SERVICE RIDE CONTROL message ON or OFF. This can be very helpful in determining if a certain portion of a circuit or a component is in working order.

The following tests are available under the Special Functions selection. The following can be commanded ON or OFF

1. Suspension damper solenoids
2. SERVICE RIDE CONTROL message

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Scan Tool Data Definitions

The electronic suspension control (ESC) scan tool data display values and definition information that can assist in diagnosing ESC related problems, especially when no diagnostic trouble codes (DTC) are stored in memory. A vehicle's scan tool data can be compared with the data display values from a known good vehicle in the scan tool data display table. When data from the vehicle differs from the typical data display value, the data definition information will help in understanding the nature of the difference and the source of the problem. This list is in alphanumeric order.

Data Definitions

Battery Voltage Signal-Range 10.0-16.0 Volts: This data refers to the battery system voltage as measured by the suspension control module.

Compressor Signal, if equipped - ON/OFF: This data indicates when the compressor relay is activated.

Digital SWPS Phase A-High/Low: This data indicates the state of phase A in the steering wheel position sensor.

Digital SWPS Phase B-High/Low: This data indicates the state of phase B in the steering wheel position sensor.

Exhaust Signal, if equipped - ON/OFF: This data indicates when the exhaust solenoid is commanded On or Off.

Left Front Damper Actuator-ON/OFF: This data refers to the state of the suspension damper solenoid contained within the shock absorber.

Left Rear Damper Actuator-ON/OFF: This data refers to the state of the suspension damper solenoid contained within the shock absorber.

LF Position Sensor-Range 0.25-4.75 volts: This data refers to the vehicle height measured in volts.

LR Position Sensor-Range 0.25-4.75 volts: This data refers to the vehicle height measured in volts.

Marker Pulse-High Low: This data indicates the state of marker pulse in the steering wheel position sensor.

Rear Leveling Air Pressure, if equipped - psi/kpa: This data indicates the system pressure in psi.

Rear Leveling Air Pressure, if equipped - Volts: This data indicates the system pressure in volts.

Right Front Damper Actuator-ON/OFF: This data refers to the state of the suspension damper solenoid contained within the shock absorber.

Right Rear Damper Actuator-ON/OFF: This data refers to the state of the suspension damper solenoid contained within the shock absorber.

RF Position Sensor-Range 0.25-4.75 volts: This data refers to the vehicle height measured in volts.

RR Position Sensor-Range 0.25-4.75 volts: This data refers to the vehicle height measured in volts.

Sensor Supply Voltage - Volts: This data indicates the voltage being supplied to the sensors from the ESC module.

Vehicle Speed - Range -193 km/h (0-120 mph): This is the ESC module measurement of the vehicle's speed from a discrete output from the powertrain control module (PCM).

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DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION

Circuit Description

The digital steering wheel position sensor inputs to the electronic suspension control (ESC) module consists of 3 digital input circuits, phase A, phase B and index marker pulse. The steering wheel position sensor supply voltage is between 4.9-5.1 volts. The information that the ESC module receives from the steering wheel position sensor is used to calculate steering angle, steering velocity and lateral acceleration. These values are used in the control of the suspension dampers.

The digital steering wheel position sensor phase A and phase B circuits are digital pulse signals whose output represents one degree of steering wheel rotation. When observing the phase A data and the phase B data parameters on the scan tool, the parameters will not have the same value at the same time. When the steering wheel is rotated, the phase A data and the phase B data parameters will be shown as high or low on the scan tool.

The index marker pulse is a digital pulse that is displayed as high on the scan tool for 20 degrees only when the steering wheel angle is between -10 and +10 degrees.

Conditions for running the DTC

Turn ON the ignition, with engine ON.

Conditions for Setting the DTC

1. The index marker pulse data parameter is high for less than 20 degrees of the steering wheel angle.
2. The index marker pulse data parameter is high for greater than 20 degrees of the steering wheel angle.
3. The index marker pulse data parameter is high when the steering wheel angle parameter is greater than +90 degrees.
4. The index marker pulse data parameter is high when the steering wheel angle parameter is less than -90 degrees.
5. The steering wheel position sensor phase A circuit is shorted to ground, open or shorted to voltage.
6. The steering wheel position sensor phase B circuit is shorted to ground, open or shorted to voltage.
7. The index marker pulse is shorted to ground, open or shorted to voltage.

Action Taken When the DTC Sets

1. The code is displayed on the scan tool as DTC C0455.
2. The suspension control defaults to firm.

Conditions for Clearing the DTC

1. Conditions for DTC are not currently present.
2. The module receives a clear code command from the scan tool.
3. The DTC clears after 100 malfunction free ignition cycles.

Diagnostic Aids

The following conditions are possible causes

1. A malfunctioning steering wheel position sensor is present.
2. A steering wheel position sensor circuit is open.
3. A steering wheel position sensor circuit was shorted.

Perform an inspection of the wiring and of the connectors. Failure to carefully inspect the wiring and the connectors may result in misdiagnosis.

Misdiagnosis causes part replacement with reappearance of the malfunction.

Steering Wheel Position Sensor - Digital Signal

1. 3 outputs used - Phase A, Phase B, Index Marker Pulse
2. Phase A & Phase B Offset PWM wave forms created when turning the wheel
3. Index marker pulse Signal is present only when steering wheel is within 10 degrees either side of center

Output is used to determine Direction of Rotation and Rate of Rotation

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The numbers below refer to the step numbers on the diagnostic table.

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1. Test for the proper operation of the phase A circuit.
2. Test for the proper operation of the phase B circuit.
3. Test for the proper operation of the index marker pulse circuit.

The electronic suspension control (ESC) module performs internal checks on hardware and software calibrations to ensure valid operation.

Upon key on with the ignition in the ON/RUN position.

The ESC module detects an error with its microprocessor.

1. Disable all functions, rear leveling and ESC.
2. The SERVICE RIDE CONTROL message will be displayed.
3. Stores a DTC C0550 in the ESC module memory.

1. Using the scan tool.
2. A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.

1. Program the ESC module and cycle the ignition Off and On to see if DTC C0550 resets. Repeat 2 times before replacement.
2. The replacement ESC module must be programmed when replacement is necessary.

The numbers below refer to the step numbers on the diagnostic table.

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1. 2. Checking to verify the DTC will not reset.
2. 3. Replace the ESC module and program.

The electronic suspension control (ESC) module performs internal checks on the software calibrations contained in the EEPROM to ensure valid operation.

Upon key on and reset.

The ESC module detects internal problems with software calibrations.

1. Disable all functions, Rear Leveling and ESC.
2. The SERVICE RIDE CONTROL message will be displayed.
3. Stores a DTC C0551 in the ESC module memory.

1. Using the scan tool.
2. A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.

1. Program the ESC module twice before replacement and cycle the ignition off and on to see if the DTC C0551 resets.
2. The replacement ESC module must be programmed when replacement is necessary. If the ESC module is not programmed after replacement, DTC C0551 is stored in the ESC module memory and will not clear until the module is programmed.

The numbers below refer to the step numbers on the diagnostic table.

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1. 2. Checks for other stored DTCs.
2. Checking to verify the DTC will not reset.

The suspension damper solenoid is driven ON and OFF by the electronic suspension control (ESC) module. To activate the suspension damper solenoid it is initially subjected to full battery voltage for a short period of time. Once the suspension damper solenoid is pulled-in the supply voltage is pulse width modulated (PWM). The amount the suspension damper solenoid valve is activated is based on inputs from the driver Tow/Haul Switch, road inputs, position sensor inputs and the powertrain control module (PCM).

The ESC module performs a test on each suspension damper solenoid during both the ON and OFF states.

1. A short to ground in the control circuit of the suspension damper solenoid
2. A short to voltage in the control circuit of the suspension damper solenoid
3. An open in the control circuit of the suspension damper solenoid
4. An open in the solenoid low reference circuit of the suspension damper solenoid
5. A short to voltage in the solenoid low reference circuit of the suspension damper solenoid

1. The suspension damper solenoid will be disabled.
2. All suspension damper solenoids will be disabled.
3. The SERVICE RIDE CONTROL message will be displayed.
4. Stores a DTC C0575, C0580, C0585 or C0590 in the ESC module memory.

1. The ESC module no longer detects a problem in the low reference circuit or the control circuit of the suspension damper solenoid.
2. Using the scan tool.
3. A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.

Important: Ignition cycle counting is used by the ESC module to detect faults in the system. The objective is to eliminate false/intermittent codes while maintaining an acceptable level of system performance. The operation of the ignition cycle counting requires that a fault condition be present for four consecutive ignition cycles before it will set the fault code and display the "SERVICE RIDE CONTROL" message. If a fault code is present (without a fault being current), the system will go into one or more degraded modes without displaying a message. Resetting the ignition cycle counter is done by clearing codes with a scan tool. Clearing codes will override ignition cycle counting for one ignition cycle. Therefore, a fault condition will set the fault code immediately if it occurs on the first ignition cycle after the codes are cleared.

If DTC C0870 or C0690 is present, repair the malfunction for these DTCs before diagnosing DTC C0575, C0580, C0585 or C0590.

It may be necessary to check TESTING FOR INTERMITTENT AND POOR CONNECTIONS in Wiring Systems.

The numbers below refer to the step numbers on the diagnostic table.

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1. 2. Checks control circuit/control module.
2. 3. Tests for low reference circuit of the suspension damper solenoid. The ESC module supplies ground of the suspension damper solenoid.
3. 4. Verifies that the resistance of the suspension damper solenoid.
4. 5. Tests the control circuit to the suspension damper solenoid for an open and short to voltage.
5. 6. Tests the control circuit for a short to ground.
6. 11. Replace and program the ESC module.

The suspension position sensor provides an analog signal voltage between 0.25 and 4.75 volts to the electronic suspension control (ESC) module.

This signal voltage represents the wheel's position relative to the body. The ESC module provides a reference and a low reference to the sensor.

Under normal driving conditions.

Vehicle speed greater than 0 km/h (0 mph).

The ESC module senses a position signal voltage below 0.25 volts or above 4.75 volts.

1. All 4 suspension damper solenoids will be commanded to their OFF state.
2. The SERVICE RIDE CONTROL message will be displayed.
3. Stores a DTC C0615, C0620, C0625 or C0630 in the ESC module memory.

1. The ESC module no longer senses a position signal voltage out of range with vehicle speed greater than 0 km/h (0 mph).
2. Using a scan tool.
3. A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.

Important: Ignition cycle counting is used by the ESC module to detect faults in the system. The objective is to eliminate false/intermittent codes while maintaining an acceptable level of system performance. The operation of the ignition cycle counting requires that a fault condition be present for four consecutive ignition cycles before it will set the fault code and display "SERVICE RIDE CONTROL" message. If a fault code is present (without a fault being current), the system will go into one or more degraded modes without displaying a message. Resetting the ignition cycle counter is done by clearing codes with a scan tool. Clearing codes will override ignition cycle counting for one ignition cycle. Therefore, a fault condition will set the fault code immediately if it occurs on the first ignition cycle after the codes are cleared.

Important: Before proceeding with the diagnosis, do a visual inspection of the mechanical aspects of the suspension position sensor and its components. Ensure the suspension position sensor and the suspension position sensor link is not bent, disconnected, or insulation on wires are not rubbed through or damaged in any way.

If DTC C0870 is present, repair the malfunction for this DTC before diagnosing DTC C0615, C0620, C0625 or C0630.

1. A faulty suspension position sensor voltage reading may result if the vehicle is or has been on a hoist that allows the suspension to hang free.
2. The following conditions may cause the malfunction to occur: A short to voltage on the 5 volt reference circuit A short to ground on the 5 volt reference circuit An open in the 5 volt reference circuit to the suspension position sensor A short to voltage on the suspension position sensor signal circuit A short to ground on the suspension position sensor signal circuit An open in the suspension position sensor signal circuit An open in the suspension position sensor low reference circuit A malfunctioning suspension position sensor A disconnected, bent or damaged suspension position sensor link

The numbers below refer to the step numbers on the diagnostic table.

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1. 2. Check the suspension position sensor data parameter.
2. 3. Tests for the proper operation of the circuit in the low voltage range.
3. 4. Tests for a short to voltage in the 5 volt reference circuit.
4. 5. Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.
5. 7. Tests for a high resistance or an open in the ground circuit.

The electronic suspension control (ESC) module provides a common low reference for all four of the suspension damper solenoids. The ESC module internally monitors the return voltage on the low reference circuit for a voltage out of range condition.

Continuously with the ignition on.

The ESC module internally senses a low reference voltage out of range condition.

1. Disable all suspension damper solenoid outputs.
2. The SERVICE RIDE CONTROL message will be displayed.
3. Stores a DTC C0690 in the ESC module memory.

1. The ESC module senses the correct voltage on the low reference circuit upon the next ignition cycle.
2. Using a scan tool.
3. A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.

Important: Ignition cycle counting is used by the ESC module to detect faults in the system. The objective is to eliminate false/intermittent codes while maintaining an acceptable level of system performance. The operation of the ignition cycle counting requires that a fault condition be present for four consecutive ignition cycles before it will set the fault code and display the "SERVICE RIDE CONTROL" message. If a fault code is present (without a fault being current), the system will go into one or more degraded modes without displaying a message. Resetting the ignition cycle counter is done by clearing codes with a scan tool. Clearing codes will override ignition cycle counting for one ignition cycle. Therefore, a fault condition will set the fault code immediately if it occurs on the first ignition cycle after the codes are cleared.

Most occurrences of this DTC are caused by connector C450 not full seated, backed out or has a bent terminal.

The following conditions may cause a malfunction to occur

1. An open in all four low reference circuits of the suspension damper solenoids
2. An open in the solenoid ground circuit at the ESC module
3. An open in G410 or SP410
4. An open in G304 or G305

The numbers below refer to the step numbers on the diagnostic table.

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1. 2. Tests whether the condition has been corrected or identified as specified in the supporting text.
2. 3. Tests all 4 low reference circuits of the suspension damper solenoids for an open.
3. 4. Tests all 4 control circuits of the suspension damper solenoids for an open.
4. 5. Tests the solenoid ground circuit at the ESC module, should be less than 0.5 ohm.
5. 7. Clear DTCs and checks to see if DTC will reset.

The electronic suspension control (ESC) module provides a common regulated voltage of approximately 5 volts to all four of the body-to-wheel suspension position sensors and air pressure sensor. The ESC module monitors this reference voltage for any malfunctions that could prevent it from outputting a regulated 5 volts.

Continuously with the ignition on.

The ESC module senses a sensor reference voltage of less than 4.0 volts or greater than 6.0 volts.

1. Disable all compressor leveling functions, and assume default pressure.
2. Disable all suspension damper solenoid outputs.
3. The SERVICE RIDE CONTROL message will be displayed.
4. Stores a DTC C0870 in the ESC module memory.

1. The ESC module senses the correct voltage output to the suspension position sensors upon the next ignition cycle.
2. Using a scan tool.
3. A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.

Important: Ignition cycle counting is used by the ESC module to detect faults in the system. The objective is to eliminate false/intermittent codes while maintaining an acceptable level of system performance. The operation of the ignition cycle counting requires that a fault condition be present for four consecutive ignition cycles before it will set the fault code and display the "SERVICE RIDE CONTROL" message. If a fault code is present (without a fault being current), the system will go into one or more degraded modes without displaying a message. Resetting the ignition cycle counter is done by clearing codes with a scan tool. Clearing codes will override ignition cycle counting for one ignition cycle.

Therefore, a fault condition will set the fault code immediately if it occurs on the first ignition cycle after the codes are cleared.

1. The following conditions may cause a malfunction to occur: A short to voltage in any one of the body-to-wheel suspension position sensor reference voltage circuit A short to ground in any one of the body-to-wheel suspension position sensor reference voltage circuit
2. If the circuit is shorted to ground, the scan tool will display all suspension position sensor voltage as zero.
3. If the circuit is shorted to an unwanted voltage source, the scan tool may display all suspension position sensor voltage as that voltage.
4. A short to voltage in the 5 volt reference of the air pressure sensor
5. A short to ground in the 5 volt reference of the air pressure sensor
6. An intermittent malfunction or DTC may cause a random firm/soft ride condition.

The numbers below refer to the step numbers on the diagnostic table.

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1. 3. Tests all suspension position sensors reference voltage circuits.
2. 4. Tests the 5 volt reference circuit of the air pressure sensor for a short to ground and a short to voltage.
3. 6. Clear DTCs and checks to see if DTC will reset.

Symptoms-Electronic Suspension Control

Important: The following steps must be completed before using the symptom tables.

1. Perform the «DIAGNOSTIC SYSTEM CHECK-ELECTRONIC SUSPENSION CONTROL»(/cadillac/escalade/gmt800-2001-2006/remont/electronic-suspension/#suspension-control-system-suspension-leveling) before using the symptom table in order to verify that all of the following are true: There are no DTCs set. The control modules can communicate via the serial data link.
2. Review the system operation in order to familiarize yourself with the system functions. Refer to «ELECTRONIC SUSPENSION CONTROL DESCRIPTION AND OPERATION»(/cadillac/escalade/gmt800-2001-2006/remont/electronic-suspension/#suspension-control-system-suspension-leveling__electronic-suspension-control-description-and-operation) .

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the ESC System. Refer to CHECKING AFTERMARKET ACCESSORIES in Wiring Systems.
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
3. Inspect the connectors to be properly seated and free of corrosion.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Check 38 way connector C405 for intermittents. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS in Wiring Systems.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. Service Ride Control Indicator Always On, See «Service Ride Control Indicator Always On»(/cadillac/escalade/gmt800-2001-2006/remont/electronic-suspension/#suspension-control-system-suspension-leveling)
2. Service Ride Control Indicator Inoperative, See «Service Ride Control Indicator Inoperative»(/cadillac/escalade/gmt800-2001-2006/remont/electronic-suspension/#suspension-control-system-suspension-leveling)

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1. Remove the right side interior trim panel. Refer to TRIM PANEL REPLACEMENT-REAR QUARTER-RIGHT (UTILITY) or TRIM PANEL REPLACEMENT-REAR QUARTER-RIGHT (SUBURBAN) in Interior Trim.
2. Disconnect the electrical connectors from the module.
3. Remove the screw.
4. Slide the module from the bracket and remove the module from the vehicle.

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1. Install the module to the vehicle by sliding the module into the bracket. NOTE: Refer to «FASTENER NOTICE»(/cadillac/escalade/gmt800-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
2. Install the screw. Tighten Tighten the screw to 1.6 N.m (14 lb in).
3. Connect the electrical connectors to the module.
4. If you are replacing the module you must recalibrate the module by performing the following procedure: Connect the scan tool to the data line connector (DLC). Turn the ignition ON with the engine OFF. Proceed per the instructions on the scan tool readout.
5. Install the right side interior trim panel. Refer to TRIM PANEL REPLACEMENT-REAR QUARTER-RIGHT (UTILITY) or TRIM PANEL REPLACEMENT-REAR QUARTER-RIGHT (SUBURBAN) in Interior Trim.

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1. Pull up on the handle at the rear of the seat to gain access to the control module.
2. Remove the retainers (1) from the control module cover (2).
3. Remove the cover (1) from the vehicle.
4. Disconnect the wiring harness (2) from the control module (3).
5. Remove the control module (1) from the vehicle.

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1. Install the control module (1) to the vehicle.
2. Connect the wiring harness (2) to the control module (3). Important: If you are replacing the module, you must program the module by performing the following procedure. Connect the scan tool to the data link connector (DLC). Turn the ignition ON with the engine OFF. Select the SPECIAL FUNCTIONS for the RTD module on the scan tool. Select the Recalibrate line under SPECIAL FUNCTIONS and follow the instructions on the scan tool and techline terminal to complete the RTD module programming. After completion of programming, return to SPECIAL FUNCTIONS on the scan tool, select ALC Trimset and follow the instructions displayed to perform the ALC trimset.
3. Install the cover (1) to the vehicle.
4. Install the retainers (1) to the control module cover (2).
5. Roll the seat downward in order to secure the seat in the original location.

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1. Raise and support the vehicle. Refer to «LIFTING AND JACKING THE VEHICLE»(/cadillac/escalade/gmt800-2001-2006/remont/hoistjack/#jacking-and-lifting-avalanche__lifting-and-jacking-the-vehicle) in General Information.
2. Disconnect the sensor harness connector from the vehicle harness connector.
3. Remove the wheel speed sensor wire from the electronic suspension control (ESC) sensor bracket.
4. Remove the wheel speed sensor wire from the ESC sensor bracket.
5. Remove the ESC sensor link bracket bolt from the upper control arm.
6. Remove the bolt from the frame.
7. Remove the position sensor from the vehicle.

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1. Install the position sensor on the vehicle. NOTE: Refer to «FASTENER NOTICE»(/cadillac/escalade/gmt800-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
2. Install the bolt to the frame. Tighten Tighten the bolts to 12 N.m (106 lb in).
3. Install the ESC sensor link bracket bolt to the upper control arm. Tighten Tighten the bolt to 9 N.m (80 lb in).
4. Install the wheel speed sensor wire from the ESC sensor bracket.
5. Install the wheel speed sensor wire to the ESC sensor bracket.
6. Connect the sensor harness connector to the vehicle harness connector.
7. Remove the safety stands.
8. Lower the vehicle.

Scheme 86

1. Raise and support the vehicle. Refer to «LIFTING AND JACKING THE VEHICLE»(/cadillac/escalade/gmt800-2001-2006/remont/hoistjack/#jacking-and-lifting-avalanche__lifting-and-jacking-the-vehicle) in General Information.
2. Disconnect the sensor harness connector from the vehicle harness connector.
3. Remove the wheel speed sensor wire from the electronic suspension control (ESC) sensor bracket.
4. Remove the ESC sensor link bracket bolt from the upper control arm.
5. Remove the bolt from the frame.
6. Remove the position sensor from the vehicle.

Scheme 87

1. Install the position sensor to the vehicle. NOTE: Refer to «FASTENER NOTICE»(/cadillac/escalade/gmt800-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
2. Install the bolt to the frame. Tighten Tighten the bolts to 12 N.m (106 lb in).
3. Install the ESC sensor link bracket bolt to the upper control arm. Tighten Tighten the bolt to 9 N.m (80 lb in).
4. Connect the sensor harness connector to the vehicle harness connector.
5. Install the wheel speed sensor wire to the ESC sensor bracket.
6. Install the ESC sensor link bracket bolt to the upper control arm.
7. Lower the vehicle.

Scheme 88

1. Raise and support the vehicle. Refer to «LIFTING AND JACKING THE VEHICLE»(/cadillac/escalade/gmt800-2001-2006/remont/hoistjack/#jacking-and-lifting-avalanche__lifting-and-jacking-the-vehicle) in General Information.
2. Disconnect the sensor harness connector from the vehicle harness connector.
3. Remove the wheel speed sensor wire from the electronic suspension control (ESC) sensor bracket.
4. Remove the ESC sensor link bracket bolt from the upper control arm.
5. Remove the bolt from the frame.
6. Remove the position sensor from the vehicle.

Scheme 89

1. Install the position sensor on the vehicle. NOTE: Refer to «FASTENER NOTICE»(/cadillac/escalade/gmt800-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
2. Install the bolt to the frame. Tighten Tighten the bolts to 12 N.m (106 lb in).
3. Install the ESC sensor link bracket bolt to the upper control arm. Tighten Tighten the bolt to 9 N.m (80 lb in).
4. Install the wheel speed sensor wire to the ESC sensor bracket.
5. Connect the sensor harness connector to the vehicle harness connector.
6. Lower the vehicle.

Tools Required

J 38185 Spring Hose Clamp Pliers

Removal Procedure

Important: Do not attempt to pry the link rod from the electronic suspension control (ESC) ball stud. If the link rod needs to be replaced or disconnected, you must use the following procedure.

Scheme 90

1. Remove the ESC sensor from the vehicle. Refer to «FRONT POSITION SENSOR REPLACEMENT-ELECTRONIC SUSPENSION (15 SERIES)»(/cadillac/escalade/gmt800-2001-2006/remont/electronic-suspension/#suspension-control-system-suspension-leveling) or «FRONT POSITION SENSOR REPLACEMENT-ELECTRONIC SUSPENSION (25 SERIES 2WD)»(/cadillac/escalade/gmt800-2001-2006/remont/electronic-suspension/#suspension-control-system-suspension-leveling) or «FRONT POSITION SENSOR REPLACEMENT-ELECTRONIC SUSPENSION (25 SERIES 4WD)»(/cadillac/escalade/gmt800-2001-2006/remont/electronic-suspension/#suspension-control-system-suspension-leveling) .
2. While supporting the sensor lever by hand, twist the link rod to remove it from the ball stud.
3. Remove the link rod from the mounting bracket ball stud.

Installation Procedure

1. Using the J 38185 install to link rod to the ball stud on the sensor lever and the mounting bracket.
2. Install the ESC sensor to the vehicle. Refer to «FRONT POSITION SENSOR REPLACEMENT-ELECTRONIC SUSPENSION (15 SERIES)»(/cadillac/escalade/gmt800-2001-2006/remont/electronic-suspension/#suspension-control-system-suspension-leveling) or «FRONT POSITION SENSOR REPLACEMENT-ELECTRONIC SUSPENSION (25 SERIES 2WD)»(/cadillac/escalade/gmt800-2001-2006/remont/electronic-suspension/#suspension-control-system-suspension-leveling) or «FRONT POSITION SENSOR REPLACEMENT-ELECTRONIC SUSPENSION (25 SERIES 4WD)»(/cadillac/escalade/gmt800-2001-2006/remont/electronic-suspension/#suspension-control-system-suspension-leveling) .

J 38185 Spring Hose Clamp Pliers

Important: Do not attempt to pry the link rod from the electronic suspension control (ESC) ball stud. If the link rod needs to be replaced or disconnected, you must use the following procedure.

Scheme 91

1. Remove the ESC sensor from the vehicle. Refer to «REAR POSITION SENSOR REPLACEMENT-ELECTRONIC SUSPENSION-LEFT (15 SERIES)»(/cadillac/escalade/gmt800-2001-2006/remont/electronic-suspension/#suspension-control-system-suspension-leveling) or «REAR POSITION SENSOR REPLACEMENT-ELECTRONIC SUSPENSION-LEFT (25 SERIES)»(/cadillac/escalade/gmt800-2001-2006/remont/electronic-suspension/#suspension-control-system-suspension-leveling) or «REAR POSITION SENSOR REPLACEMENT-ELECTRONIC SUSPENSION-RIGHT»(/cadillac/escalade/gmt800-2001-2006/remont/electronic-suspension/#suspension-control-system-suspension-leveling) .
2. While supporting the sensor lever by hand, twist the link rod to remove it from the ball stud.
3. Remove the link rod from the frame bracket ball stud.

1. Using the J 38185 install to link rod to the ball stud on the sensor lever and the frame bracket.
2. Install the ESC sensor to the vehicle. Refer to «REAR POSITION SENSOR REPLACEMENT-ELECTRONIC SUSPENSION-LEFT (15 SERIES)»(/cadillac/escalade/gmt800-2001-2006/remont/electronic-suspension/#suspension-control-system-suspension-leveling) or «REAR POSITION SENSOR REPLACEMENT-ELECTRONIC SUSPENSION-LEFT (25 SERIES)»(/cadillac/escalade/gmt800-2001-2006/remont/electronic-suspension/#suspension-control-system-suspension-leveling) or «REAR POSITION SENSOR REPLACEMENT-ELECTRONIC SUSPENSION-RIGHT»(/cadillac/escalade/gmt800-2001-2006/remont/electronic-suspension/#suspension-control-system-suspension-leveling) .

Scheme 92

1. Raise and support the vehicle. Refer to «LIFTING AND JACKING THE VEHICLE»(/cadillac/escalade/gmt800-2001-2006/remont/hoistjack/#jacking-and-lifting-avalanche__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the wheel and tire assembly from the vehicle. Refer to TIRE AND WHEEL REMOVAL AND INSTALLATION in Tires and Wheels.
3. Disconnect the sensor harness connector from the vehicle harness connector.
4. Remove the bolt from the electronic suspension control (ESC) sensor link bracket.
5. Spread the bracket open until the bracket can be removed from the upper control arm.
6. Remove the bolts from the frame.
7. Remove the position sensor from the vehicle.

Scheme 93

Scheme 94

1. Install the position sensor on the vehicle. NOTE: Refer to «FASTENER NOTICE»(/cadillac/escalade/gmt800-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
2. Install the bolts to the frame. Tighten Tighten the bolts to 12 N.m (106 lb in).
3. Close the bracket around the upper control arm making sure the bracket rests between the locating stops.
4. Install the bolt. Tighten Tighten the bolt to 25 N.m (18 lb ft).
5. Connect the sensor harness connector to the vehicle harness connector.
6. Install the wheel and tire assembly to the vehicle. Refer to TIRE AND WHEEL REMOVAL AND INSTALLATION in Tires and Wheels.
7. Lower the vehicle.

Scheme 95

Scheme 96

1. Raise the vehicle. Refer to «LIFTING AND JACKING THE VEHICLE»(/cadillac/escalade/gmt800-2001-2006/remont/hoistjack/#jacking-and-lifting-avalanche__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the wheel from the vehicle. Refer to TIRE AND WHEEL REMOVAL AND INSTALLATION in Tires and Wheels.
3. Disconnect the sensor harness connector from the vehicle harness connector.
4. Remove the bolts.
5. Remove the position sensor from the vehicle.
6. Disconnect the sensor link from the ball stud.

Scheme 97

Scheme 98

1. Install the position sensor on the vehicle. NOTE: Refer to «FASTENER NOTICE»(/cadillac/escalade/gmt800-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
2. Install the bolts. Tighten Tighten the bolts to 12 N.m (106 lb in).
3. Connect the sensor link to the ball stud.
4. Connect the sensor harness connector to the vehicle harness connector.
5. Install the wheel to the vehicle. Refer to TIRE AND WHEEL REMOVAL AND INSTALLATION in Tires and Wheels.
6. Lower the vehicle.

Scheme 99

Scheme 100

1. Raise the vehicle. Refer to «LIFTING AND JACKING THE VEHICLE»(/cadillac/escalade/gmt800-2001-2006/remont/hoistjack/#jacking-and-lifting-avalanche__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the wheel from the vehicle. Refer to TIRE AND WHEEL REMOVAL AND INSTALLATION in Tires and Wheels.
3. Disconnect the sensor harness connector from the vehicle harness connector.
4. Disconnect the sensor link from the ball stud.
5. Remove the bolts.
6. Remove the position sensor from the vehicle.

Scheme 101

Scheme 102

1. Install the position sensor on the vehicle. NOTE: Refer to «FASTENER NOTICE»(/cadillac/escalade/gmt800-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
2. Install the bolts. Tighten Tighten the bolts to 12 N.m (106 lb in).
3. Connect the sensor link to the ball stud.
4. Connect the sensor harness connector to the vehicle harness connector.
5. Install the wheel to the vehicle. Refer to TIRE AND WHEEL REMOVAL AND INSTALLATION in Tires and Wheels.
6. Lower the vehicle.

Electronic Suspension Control Description and Operation

The electronic suspension control (ESC) system is bi-state real time damping system. The ESC module controls the suspension damper solenoids and suspension position sensors, along with parts of the automatic level control (ALC) system, if 1500 series.

The ESC system consists of the following

1. The ESC module
2. The compressor/leveling module, if 1500 series The air pressure sensor, if 1500 series The exhaust solenoid, if 1500 series
3. The compressor motor relay, if 1500 series
4. The steering handwheel speed/position sensor
5. The suspension damper solenoids
6. The suspension position sensors

Electronic Suspension Control (ESC) Module

The objective of the ESC module is to provide ride and handling results that are superior to a passive damper system, both on and off road at all load conditions. The ESC module monitors body-to-wheel height, vehicle speed, handwheel position/speed, lift/dive status and a driver tow/haul input switch status in real time and instantly selects a "normal" or "firm" mode. This is done for each of the front and rear shock absorbers in order to adjust the vehicle for specific road and driving conditions.

The ESC module will also use the rear body-to-wheel displacements and vehicle speed inputs to keep the rear trim height of the vehicle at its desired level. The ESC module will stay awake for approximately ten minutes after ignition off on 1500 series equipped with Automatic Level Control. For more information on the ALC system, refer to AUTOMATIC LEVEL CONTROL DESCRIPTION AND OPERATION in Automatic Level Control.

Ignition cycle counting is used by the ESC module to detect faults in the system. The objective is to eliminate false/intermittent codes while maintaining an acceptable level of system performance. The operation of the ignition cycle counting requires that a fault condition be present for four consecutive ignition cycles before it will set the fault code and display the "SERVICE RIDE CONTROL" message. If a fault code is present (without a fault being current), the system will go into one or more degraded modes without displaying a message. Resetting the ignition cycle counter is done by clearing codes with a scan tool. Clearing codes will override ignition cycle counting for one ignition cycle. Therefore, a fault condition will set the fault code immediately if it occurs on the first ignition cycle after the codes are cleared.

Position Sensors

The ESC module provides a common regulated voltage of approximately 5 volts to all 4 of the body-to-wheel suspension position sensors and to the air pressure sensor. The ESC module receives vehicle speed sensor (VSS) discrete output from the PCM. The suspension position sensors provide an analog signal voltage between 0.5 and 4.5 volts to the ESC module. This signal voltage represents the wheel's position relative to the body. The ESC module provides a 5 volt reference and a low reference to the suspension position sensors.

Shock Absorbers

The damper consists of an in-piston two position solenoid with a 1.5-3.3 ohm coil. The response time of the damper is less than 40 ms. The damper is using movement of oil through an orifice for the damping effect.

The suspension damper solenoid is driven ON and OFF by the ESC module. To activate the solenoid, it is initially subjected to full battery voltage for a short period of time. Once the solenoid is pulled-in, the supply voltage is pulse width modulated (PWM). The amount the suspension damper solenoid is activated is based on inputs from the driver Tow/Haul switch, road inputs, position sensor inputs and the powertrain control module (PCM). The ESC module provides a common ground for all 4 of the suspension damper solenoids.

Vehicle Speed

The ESC module receives a vehicle speed input. It is obtained over the CLASS 2 serial communication buss. Vehicle speed is used to determine the amount of damper control necessary.

Warning Message

The SERVICE RIDE CONTROL message is displayed in the IPC message center, depending on the fault that has been encountered. The warning message will be continued to be displayed, until the fault has been corrected.

Scheme 103

See also:
• FASTENER NOTICE
• LIFTING AND JACKING THE VEHICLE
• DIAGNOSTIC SYSTEM CHECK-ELECTRONIC SUSPENSION CONTROL
• ELECTRONIC SUSPENSION CONTROL DESCRIPTION AND OPERATION
• SCAN TOOL DATA DEFINITIONS