Data Display

The scan tool displays the module data. This information assists in determining whether the module is operating properly, and whether the module is sending or receiving the proper data to and from a particular system. The module uses data received from other systems in order to carry out some functions. If the module receives the incorrect data from another system, the module may function improperly. Use the scan tool in order to review the data from the systems that interact with the module.

Displayed Input/Output Status

The scan tool also displays the module input/output status. Select the module input/output status display in order to display the data and determine if the switched inputs/outputs may be properly interpreted. The display also indicates if the input/output has changed states. For example, when a door is closed, the scan tool displays the input status of the door ajar switch as INACTIVE. When the door is open, the scan tool reads ACTIVE. Use this type of information when diagnosing a malfunction associated with a particular module input or an input that is shared with another system.

Control Outputs

Use a scan tool in order to control the module output functions. When the module output control is selected, the scan tool can command the module to turn an output on or off. This feature may be used in order to determine if the module is able to control an output regardless of the inputs or any specific program instructions. Once a test is selected, the scan tool will command the module to energize the selected output. The scan tool then displays the status of the selected output. The displayed information represents only what was module commanded, not what action was actually taken. Verify that the module is performing each of the selected output functions.

Scan Tool Menus

Refer to the Scan Tool Manual for complete information on scan tool diagnostics. The following selections appear under Delco/Bosch ABS/TCS ICCS (if equipped). The VSES (ICCS) system is optional and will only appear if equipped.

Diagnostic Trouble Codes (DTC)

The diagnostic trouble codes (DTC) function has the following 3 modes:

DTC Information: Current or history DTCs stored by the EBCM may be displayed.

DTC History: Displays the conditions under which a history DTC was set and the number of occurrences of the DTC.

Clear DTC Information: Current or history DTCs stored by the EBCM may be cleared.

Data Display 1 Diagnostics

For the Data Display parameters, refer to Scan Tool Data List and Scan Tool Data Definitions .

Data Display 2 Normal Mode

This test is used to monitor the class 2 serial data messages that relate to the ABS/TCS/VSES (if equipped). Only the parameters of the options that the vehicle is equipped will be displayed. The scan tool will display a value only when there is a class 2 serial data message that relates to the individual parameter. Otherwise, the scan tool displays all asterisks next to each parameter.

Brake Switch - ABS Input: Scan tool displays: Applied/Released - Display indicates the state of the brake switch as seen by the EBCM.

Brake Switch - PCM Input: Scan tool displays: Applied/Released - Display indicates the state of the brake switch as seen by the PCM.

Brake Travel Switch - PCM Input: Scan tool displays: Applied/Released - Display indicates the state of the extended brake travel switch.

ABS Failed Lamp Command: Scan tool displays: Yes/No - Display indicates if the EBCM is commanding the ABS indicator ON.

Traction Control Equipped: Scan tool displays: Yes/No - Display indicates if the vehicle is equipped with Traction Control.

Traction Engaged Message Command: Scan tool displays: Yes/No - Display indicates if the EBCM is commanding the TRACTION ENGAGED message to be displayed on the DIC.

Traction Suspended Message Command: Scan tool displays: Yes/No - Display indicates if the EBCM is commanding the TRACTION SUSPENDED message to be displayed on the DIC.

Traction Off Message Command: Scan tool displays: Yes/No - Display indicates if the EBCM is commanding the TRACTION OFF message to be displayed on the DIC.

Traction Ready Message Command: Scan tool displays: Yes/No - Display indicates if the EBCM is commanding the TRACTION READY message to be displayed on the DIC.

Temporary Inhibit of TCS: Scan tool displays: Yes/No - Display indicates if the PCM has suspended the TCS due to a malfunction or due to the driver using the traction control switch.

Powertrain TCS Failure: Scan tool displays: Yes/No - Display indicates if the PCM has suspended the TCS due to a malfunction related to TCS.

Suspension System Failure: Scan tool displays: Yes/No - Display indicates if the suspension system is inactive due to a malfunction.

Service Steering Message Command: Scan tool displays: Yes/No - Display indicates if the EBCM is commanding the SERVICE STEERING SYS message to be displayed on the DIC.

Service Stability System: Scan tool displays: Yes/No - Display indicates if the EBCM has disabled VSES due to a malfunction

Stability System Engaged: Scan tool displays: Yes/No - Display indicates if the EBCM is commanding the STABILITY SYS ENGAGED message to be displayed on the DIC

Service Stability Message Command: Scan tool displays: Yes/No - Display indicates if the EBCM is commanding the SERVICE STABILITY SYS message to be displayed on the DIC.

Snapshot

In this test mode, the scan tool captures the data listed in the data displays before and after a snapshot-triggering condition which may or may not set a DTC. Refer to Scan Tool Snapshot Procedure in Wiring Systems.

Special Functions

In this test mode, the scan tool may be used in order to perform functional tests on the system which help verify proper operation. Malfunction conditions may be further identified by testing and observing the test results. You must first clear any DTCs before any tests in Special Functions may be performed. Only the test that are equipped on the vehicle will be displayed. The Special Functions are grouped in the following manner:

The Special Functions are detailed below.

Solenoid Test-Pressure Hold

This test activates the selected wheel circuit inlet valve, placing the valve in the pressure hold position. When the valve is in the pressure hold position, the valve will not allow master cylinder pressure to be delivered to the hydraulic wheel circuit. This is done under actual operating conditions when the EBCM determines that the wheel is moving too slowly. The EBCM holds additional master cylinder pressure from the hydraulic wheel circuit in an attempt to allow the circuit to rotate at an appropriate speed. The scan tool commands the valve to close. This should allow the technician to spin the wheel even though an assistant is applying pressure to the brake pedal. Perform the following test:

1. Turn OFF the ignition.
2. Install a scan tool.
3. Turn ON the ignition, with the engine OFF.
4. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information. Ensure that all of the wheels are about 15 cm (6 in) off of the floor.
5. Place the gear selector in the NEUTRAL position.
6. Select the Special Functions from the Delco/Bosch ABS/TCS ICCS (if equipped) menu.
7. Select the Solenoid Test. Have an assistant command Inlet Valve Solenoid of the appropriate wheel using the scan tool.
8. Have the assistant press and hold the brake pedal.
9. Attempt to move the wheel being tested by hand. The wheel should move even though the assistant is applying pressure to the brake pedal. The front wheels may be difficult to turn by hand, but may be moved if the system is working properly.

Solenoid Test-Pressure Release

This test activates the selected hydraulic wheel circuit outlet valves, placing them in the pressure reduce position. When in the pressure reduce position, the valve will allow wheel caliper pressure to be returned to the master cylinder circuit. This is done under actual operating conditions because the EBCM has determined that the wheel is moving too slowly, and holding additional master cylinder pressure from it has not allowed it to rotate at an appropriate speed. The scan tool commands the valves to these positions which should allow the technician to spin the wheel even though an assistant is applying pressure to the brake pedal. Perform the following test:

1. Turn OFF the ignition.
2. Install a scan tool.
3. Turn ON the ignition, with the engine OFF.
4. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information. Ensure that all of the wheels are about 15 cm (6 in) off of the floor.
5. Place the gear selector in the NEUTRAL position.
6. Select the Special Functions from the Delco/Bosch ABS/TCS ICCS (if equipped) menu.
7. Select the Solenoid Test. Have an assistant command the Outlet Valve Solenoid of the appropriate wheel using the scan tool.
8. Have the assistant press and hold the brake pedal.
9. Attempt to move the wheel being tested by hand. The wheel should move even though the assistant is applying pressure to the brake pedal. The front wheels may be difficult to turn by hand, but may be moved if the system is working properly.

Automated Bleed

The Automated Bleed mode of the scan tool is used during bleeding of the ABS System. Refer to Antilock Brake System Automated Bleed Procedure .

Automated Test

This test cycles each valve solenoid and the pump motor (as well as the necessary relays) in order to verify component operation. This test is identical to the Initialization Sequence. If a malfunction is detected, the EBCM will set DTCs. The DTCs will be displayed upon completion of the test. Perform the following test:

1. Turn OFF the ignition.
2. Install a scan tool.
3. Turn ON the ignition, with the engine OFF.
4. Select the Special Functions from the Delco/Bosch ABS/TCS ICCS (if equipped) menu.
5. Select the Automated Test.
6. Run the Automated Test.
7. Record any DTCs that were set.

Lamp/Message(s) Test

TCS Indicator Lamp: Controls the operation of the TRACTION CONTROL indicator

ABS Indicator Lamp: Controls the operation of the ABS indicator

Traction Engaged Message: Controls the operation of the TRACTION ENGAGED message on the DIC

Service Stability System Message: Controls the operation of the SERVICE STABILITY SYS message on the DIC

Stability Engaged Message: Controls the operation of the STABILITY SYS ENGAGED message on the DIC

TCS Test

This test runs the pump motor in order to apply fluid pressure to the front wheel circuits.

Perform the following test. This test does NOT require an assistant:

1. Turn OFF the ignition.
2. Install a scan tool.
3. Turn ON the ignition, with the engine OFF.
4. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information. Ensure that all of the wheels are about 15 cm (6 in) off of the floor.
5. Select the Special Functions from the Delco/Bosch ABS/TCS ICCS (if equipped) menu.
6. Select the TCS Test.
7. Command the TCS Test ON with the scan tool. The pump motor will turn on for approximately 25 seconds.
8. Attempt to move each front wheel by hand. The wheels should not move due to the pump motor running and applying pressure to the front wheels.

ICCS2 Data Link Test

This test will ensure that the wires are not crossed between the EBCM and the CVRSS module. The two mode are the following:

The test first checks for any EBCM or CVRSS DTCs. If any EBCM or CVRSS codes are set then this test will not run. If the test is successful the scan tool will display a test complete message. If the wires are crossed and this test is run the scan tool will display an electrical malfunction message.

Steering Position Sensor Test

This test monitors the analog and digital steering angle position. Perform the following test only after the steering wheel position sensor (SWPS) has been centered:

1. Turn OFF the ignition.
2. Install a scan tool.
3. Start the engine.
4. Place the gear selector in the PARK position.
5. Turn the steering wheel to the left lock position.
6. Select the Special Functions from the Delco/Bosch ABS/TCS ICCS (if equipped) menu.
7. Select the Steering Position Sensor Test.
8. When the scan tool displays Turn Steering Wheel, turn the steering wheel once to the right lock position.
9. The scan tool will display whether or not the steering wheel position sensor passes the test.