The scan tool used provides the following capabilities:

Make sure the scan tool contains updated software before attempting to communicate with the ABS system. To use the scan tool, connect it to the Data Link Connector (DLC) and turn the ignition switch to the ON position. The scan tool reads serial data sent from the Electronic Brake Control Module (EBCM) Serial Data output terminal B7 to the DLC terminal 2.

The ABS Scan Tool Data List contains all ABS and 4WD related parameters that are available on the scan tool. The list is arranged in alphabetical order.

Use the ABS Scan Tool Data List only after the following are determined:

Use scan tool values from a properly operating system for comparison with the ABS system you are diagnosing. The ABS Scan Tool Data List represents values seen on a properly operating system.

Important: Confirm that the scan tool that you are using is functioning properly. Use of a malfunctioning scan tool can result in a misdiagnosis and unnecessary parts replacement.

Only the parameters listed below are referenced in this service manual for use in diagnosis. If all values are within the typical range described below, refer to Intermittents and Poor Connections for diagnosis.

Scan Tool Data List

Ignition ON, Engine OFF, Transmission in Neutral or Park, Transfer Case in 2WD, and Brake Unapplied
Scan Tool Parameter	Data List	Units Displayed	Typical Data Value
ABS Active	ABS/4WD	No/Yes	No
ABS Relay Command	ABS	On/Off	On
ABS Relay Feedback	ABS	On/Off	On
ABS Warning Lamp	ABS	On/Off	Off
Accelerometer Status	4WD	•  OK     •  Short to Ground     •  Unreasonably Low     •  Unreasonably High     •  Open	OK
Brake Switch Status	ABS/4WD	Applied/Released	Released
Idle Up Circuit	4WD	OK/Failed	OK
Ignition Voltage	ABS/4WD	Volts	Varies
Left Front Wheel Speed	ABS/4WD	mph/km/h	0
Left Rear Wheel Speed	ABS/4WD	mph/km/h	0
LF Inlet Valve Solenoid	ABS	Active/Inactive	Inactive
LF Outlet Valve Solenoid	ABS	Active/Inactive	Inactive
Pump Motor Commanded State	ABS	On/Off	Off
Pump Motor Feedback State	ABS	On/Off	Off
Rear Inlet Valve Solenoid	ABS	Active/Inactive	Inactive
Rear Outlet Valve Solenoid	ABS	Active/Inactive	Inactive
RF Inlet Valve Solenoid	ABS	Active/Inactive	Inactive
RF Outlet Valve Solenoid	ABS	Active/Inactive	Inactive
Right Front Wheel Speed	ABS/4WD	mph/km/h	0
Right Rear Wheel Speed	ABS/4WD	mph/km/h	0
Rough Road Parameter	ABS/4WD	g	0.00
Switched Battery Voltage	ABS/4WD	Volts	Varies
Vehicle Speed	ABS/4WD	mph/km/h	0
4WD Status	4WD	Two Wheel Drive/Four Wheel Drive	Two Wheel Drive
4WD Switch	4WD	Normal/Open	Normal

Scan Tool Data Definitions

The Data Display function contains lists of ABS and 4WD data parameters. A brief description of all ABS and 4WD data parameters available on the scan tool are listed below: The list is arranged in alphabetical order.

ABS Active: This parameter indicates if the vehicle is currently in an ABS event or not.

ABS Relay Command: This display indicates the commanded state of the electronic brake control relay.

ABS Relay Feedback: This display indicates the actual state of the electronic brake control relay.

ABS Warning Lamp: This indicates the state of the ABS indicator.

Accelerometer Status: This indicates the state of the longitudinal accelerometer.

Brake Switch Status: This parameter indicates the state of the brake switch.

Idle Up Circuit: This parameter checks the continuity of the idle up circuit between the EBCM and the PCM.

Ignition Voltage: This parameter is the ignition voltage at the EBCM.

Left Front Wheel Speed: Display shows actual wheel speed of the left front wheel.

Left Rear Wheel Speed: Display shows actual wheel speed of the left rear wheel.

LF Inlet Valve Solenoid: This display indicates the commanded state of the left front inlet solenoid valve.

LF Outlet Valve Solenoid: This display indicates the commanded state of the left front outlet solenoid valve.

Pump Motor Commanded State: This display indicates the commanded state of the ABS pump motor.

Pump Motor Feedback State: This display indicates the actual state of the ABS pump motor.

Rear Inlet Valve Solenoid: This display indicates the commanded state of the rear inlet solenoid valve.

Rear Outlet Valve Solenoid: This display indicates the commanded state of the rear outlet solenoid valve.

Right Front Wheel Speed: Display shows actual wheel speed of the right front wheel.

Right Rear Wheel Speed: Display shows actual wheel speed of the right rear wheel.

RF Inlet Valve Solenoid: This display indicates the commanded state of the right front inlet solenoid valve.

RF Outlet Valve Solenoid: This display indicates the commanded state of the right front outlet solenoid valve.

Rough Road Parameter: This parameter, calculated from wheel speed sensor data, represents the rapid variation or acceleration in g's of the driven wheel speeds due to a rough road. A rough road will cause torque to be applied to the drivetrain which may be detected by the PCM's OBD II misfire diagnostic as a false misfire. This rough road detection data is sent to the PCM via serial data. The PCM will disable the OBD II misfire diagnostic during rough road detection since this could be interpreted as misfire.

Switched Battery Voltage: This parameter is the battery voltage available at the solenoid valves and the pump motor when the solenoid valve control relay is energized.

Vehicle Speed: Scan tool range 0-200 km/h/0-125 MPH. This parameter displays the vehicle speed. The Powertrain Control Module (PCM) receives reference pulses from the Vehicle Speed Sensor (VSS) and converts them into km/h or MPH for display.

4WD Status: This parameter indicates the actual state of the transfer case 4WD selector.

4WD Switch: This parameter indicates the state of the 4WD switch.