GM Service Manual Online
For 1990-2009 cars only

Transfer Case Shift Control Module Scan Tool Information BW4477

Table 1: Scan Tool Data Parameters
Table 2: Scan Tool Output Controls

The Transfer Case Shift Control Module Scan Tool Data List contains all transfer case related parameters that are available on the scan tool. The list is arranged in alphabetical order. A given parameter may appear in any one of the data lists, and in some cases may appear more than once, or in more than one data list in order to group certain related parameters together.

The values below represent a typical display recorded from a properly functioning system.

Important: Do not use a scan tool that displays faulty data. Report the condition to the scan tool manufacturer. The use of a faulty scan tool can result in misdiagnosis and the unnecessary replacement of parts.

Only the parameters listed below are used/referenced in this manual for diagnosis. If a scan tool displays other parameters, those values are not recommended by General Motors for use in diagnosis.

If all values are within the expected range described below, refer to Symptoms - Transfer Case for diagnosis.

The scan tool values from a properly functioning transfer case may be used for comparison with the transfer case you are diagnosing. The values below represent a typical display recorded from a properly functioning system.

Scan Tool Data Parameters

Parameter

System State

Expected Value

Description

Operating Conditions: Engine at idle, upper radiator hose hot, closed throttle, gear in Park or Neutral, accessories OFF

Accelerator Pedal Position

0-100%

0%

This parameter displays percentage of pedal depression.

Average Speed

km/h

0 km/h

This parameter displays the vehicle speed in km/h.

AWD Minispare Disable

Yes/No

No

This parameter displays On when a minispare is present.

Base Model Part Number

Part Number

GM Part Number

This parameter displays an 8 digit GM part number.

Battery Voltage

Volts

Battery Voltage

This parameter displays battery voltage.

Calibration part Number

Part Number

GM Part Number

This parameter displays an 8 digit GM part number.

Calculated Clutch Temperature

Degrees C

Same as oil temperature

This parameter displays clutch temperature in degrees Celsius.

Clutch Coupling

0-100%

0%

This parameter displays the amount of clutch activation shown in percentage.

Clutch Overtemp Counter

0

Counts

This parameter displays the amount of clutch overtemps that have occurred.

Clutch Resistor Value

Volts Resistor Dependent

Volts

This parameter displays the return voltage or the signal voltage that comes back from the instrument panel switch.

Clutch Resistor Supply

5 volts

Volts

This parameter displays the 5 volt reference being fed to the IP switch.

Clutch Temp. Sensor

3.5 volts

Volts

This parameter displays temperature in voltage.

Clutch Torque

Varies

N·m

This parameter displays the amount of torque in N·m.

End Model Part Number

Part Number

GM Part Number

This parameter displays an 8 digit GM part number.

Left Front Wheel Speed

0 km/h

km/h

This parameter displays the wheel speed in km/h.

Left Rear Wheel Speed

0 km/h

km/h

This parameter displays the wheel speed in km/h.

Ignition Accessory Signal

On

On/Off

This parameter displays On or Off.

Ignition Run/Crank

On

On/Off

This parameter displays if the run/crank voltage is seen at the module.

Odometer

km

km

This parameter displays the vehicle mileage in km.

Requested Clutch Torque

Varies

N·m

This parameter displays the amount of clutch torque being requested based on engine torque and accelerator position as well as other inputs.

Right Front Wheel Speed

0 km/h

km/h

This parameter displays the wheel speed in km/h.

Right Rear Wheel Speed

0 km/h

km/h

This parameter displays the wheel speed in km/h.

Service AWD Indicator

No

Yes/No

This parameter displays On if the transfer case shift control module commands the Service AWD Indicator On. The scan tool displays On or Off.

Software Part Number

Part Number

GM Part Number

This parameter displays the 8 digit part number.

Steering Wheel Angle

Varies

Degrees

This parameter displays the current position of the steering wheel in degrees.

Trans. Fluid Temp

Varies

Degrees C

This parameter displays the transmission fluid temperature in degrees Celsius.

Transfer Case Position

Auto 4WD

Auto 4WD/2WD

This parameter displays the current mode of the transfer case AWD/2WD.

Transfer Case Oil Temp

Varies

Degrees C

This parameter displays the transfer case oil temperature in degrees Celsius.

Transfer Case Clutch Command

0%

0-100%

This parameter displays the amount in percentage of clutch activation being requested.

Transmission OSS

0 km/h

km/h

This parameter displays vehicle speed.

TR Switch Status

Varies

1st-6th gears

This parameter displays the current range the transmission is in.

Vehicle Speed

0 km/h

km/h

This parameter displays vehicle speed in kilometers per hour.

Warm-Ups Since Last DTC

0 Counts

Counts

This parameter displays the amount of warm up cycles since a current DTC was set.

Scan Tool Output Controls

Output Control

Description

Refer to the scan tool manual for complete scan tool operating instructions.

Clutch Control

This function allows the technician to command the clutch coil high side driver on or off.

Clutch Coupling Request

This function allows the technician to command the clutch coil to be energized from 0-100 percent PWM.

Clutch Return

This function allows the technician to command the clutch coil low side driver on or off.

Reset Clutch Overtemp Counter

This function allows the technician to command the over temperature counter to be zeroed.