Transmission Control Module Scan Tool Information

The Transmission Control Module Scan Tool Data List contains all transmission 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.

NOTE:

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 - Automatic Transmission for diagnosis.

The scan tool values from a properly functioning transmission may be used for comparison with the transmission 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, transmission in Park, closed loop operation, accessories OFF, brake pedal not applied.
Calculated Clutch 1 Torque	Y (lb ft)	-3.7 lb ft	The transmission control module calculates the torque applied to each clutch in the transmission. This parameter displays the calculated torque value for Clutch 1.
Calculated Clutch 2 Torque	Y (lb ft)	-3.7 lb ft	The transmission control module calculates the torque applied to each clutch in the transmission. This parameter displays the calculated torque value for Clutch 2.
Calculated Clutch 3 Torque	Y (lb ft)	49.9 lb ft	The transmission control module calculates the torque applied to each clutch in the transmission. This parameter displays the calculated torque value for Clutch 3.
Calculated Line Pressure	kPa (PSI)	46.4 psi	This parameter indicates the expected real line pressure after accounting for pump loss factors.
Calculated Throttle Position	%	0%	This parameter contains the accelerator effective position, which represents the driver's intended request for torque or acceleration. It is determined from the maximum of the driver requests to open the throttle (e.g., accelerator pedal, cruise control, etc.) and is normalized to 0 to 100%, where 0% represents an idle or coast request and 100% represents a request for wide open throttle (WOT). Calculated throttle position displays a throttle position that is calculated. Meaning idle is 0% (even though the throttle is slightly open at idle) and wide open throttle is 100% (Which may be less than fully open).
Clutch 1 Slip Speed	RPM	0	This parameter represents the clutch slip in RPM for the Variable low and 1-2 reverse clutch (C1) Clutch. When a clutch is engaged it is monitored to see if it is working properly. A clutch is a material which connects (couples) two shafts or other components together when desired. For example: When the clutch is engaged, the event results in both shafts spinning at the same speed. When it is disengaged, one shaft will spin while the other remains stationary. If after engagement they are not spinning at the same speed it is considered slipping.
Clutch 1 Status	Applied / Released	Applied	This parameter represents the clutch status engaged or disengaged. When a clutch is engaged it is monitored to see if it is working properly. A clutch is a material which connects (couples) two shafts or other components together when desired. For example: When the clutch is engaged, the event results in both shafts spinning at the same speed. When it is disengaged, one shaft will spin while the other remains stationary. If after engagement they are not spinning at the same speed it is considered slipping.
Clutch 1 Torque Command	Y (lb ft)	-3.7 lb ft	This parameter displays the serial data command to control the torque at clutch 1.
Clutch 2 Slip Speed	RPM	-1400 RPM	This parameter represents the clutch slip in RPM for the variable hi and 2-3-4 (C2) Clutch Slip. When a clutch is engaged it is monitored to see if it is working properly. A clutch is a material which connects (couples) two shafts or other components together when desired. For example: When the clutch is engaged, the event results in both shafts spinning at the same speed. When it is disengaged, one shaft will spin while the other remains stationary. If after engagement they are not spinning at the same speed it is considered slipping.
Clutch 2 Status	Applied / Released	Released	This parameter represents the clutch status engaged or disengaged status of the variable hi and 2-3-4 (C2) clutch. When a clutch is engaged it is monitored to see if it is working properly. A clutch is a material which connects (couples) two shafts or other components together when desired. For example: When the clutch is engaged, the event results in both shafts spinning at the same speed. When it is disengaged, one shaft will spin while the other remains stationary.
Clutch 2 Torque Command	Y (lb ft)	-3.7 lb ft	This parameter displays the serial data command to control the torque at the variable hi and 2-3-4 clutch.
Clutch 3 Slip Speed	RPM	0 RPM	This parameter represents the clutch slip in RPM for the 1-3 reverse clutch assembly (C3) Clutch Slip. When a clutch is engaged it is monitored to see if it is working properly. A clutch is a material which connects (couples) two shafts or other components together when desired. For example: When the clutch is engaged, the event results in both shafts spinning at the same speed. When it is disengaged, one shaft will spin while the other remains stationary. If after engagement they are not spinning at the same speed it is considered slipping.
Clutch 3 Status	Applied / Released	Applied	This parameter represents the 1-3 reverse clutch assembly (C3) status engaged or disengaged. When a clutch is engaged it is monitored to see if it is working properly. A clutch is a material which connects (couples) two shafts or other components together when desired. For example: When the clutch is engaged, the event results in both shafts spinning at the same speed. When it is disengaged, one shaft will spin while the other remains stationary.
Clutch 3 Torque Command	Y (lb ft)	49.4 lb ft	This parameter displays the serial data command to control the torque at 1-3 reverse clutch assembly.
Distance Since DTC Cleared	km / miles	Varies	This parameter displays the distance in miles or kilometers since engine control module diagnostic trouble codes (DTCs) have been cleared using the scan tool.
Distance Since First Malfunction	km / miles	Varies	This parameter displays the distance in miles or kilometers since the time that a failure record was first captured for a diagnostic failure.
Distance Since Last Malfunction	km / miles	Varies	This parameter displays the distance in miles or kilometers since the time that a failure record was last captured for a diagnostic failure.
Distance with MIL On	km / miles	Varies	This parameter displays the accumulated distance driven with the malfunction indicator lamp (MIL) on.
Driver Requested Axle Torque	Y (lb ft)	-4.4 lb ft	This parameter displays the vehicle operator's requested amount of torque to be provided to the axle. Torque is the measured ability of a rotating element, as of a gear or shaft (axle), to overcome turning resistance.
Engine Coolant Temperature	°C (°F)	83°C (181°F)	This parameter displays the temperature of the engine coolant (fluid used to cool a system by transferring heat away from one part to another).
Engine Speed	RPM	1400 RPM	Indicates the speed of the internal combustion engine in rpm.
Engine Torque	Y (lb ft)	Varies	This parameter displays the amount of torque currently being produced by the engine as a percentage of total available. Torque is the twisting force created in an engine by rotating parts.
High Side Driver 1	On / Off	Enabled	This displays the current state of the high side driver 1 which provides supply voltage to the pressure control solenoids. A solenoid valve which controls fluid pressure to a transmission fluid passage.
High Side Driver 1 Circuit High Voltage Test Status	OK, Malfunction, Not Run	OK	This contains the status of the high voltage test for the shared high side driver circuit. The high side driver is output from the transmission control module that supplies the voltage to the component.
High Side Driver 1 Circuit Low Voltage Test Status	OK, Malfunction, Not Run	OK	This contains the status of the low voltage test for the shared high side driver circuit. The high side driver is output from the computer that supplies the voltage to the control solenoid valve assembly.
High Side Driver 1 Circuit Open Test Status	OK, Malfunction, Not Run	OK	This contains the status of the open test for the shared high side driver circuit. The high side driver is output from the computer that supplies the voltage to the control solenoid valve assembly.
High Side Driver 2	On / Off	Enabled	This displays the current state of the high side driver 2 which is a Power switching device on the positive side.
High Side Driver 2 Circuit High Voltage Test Status	OK, Malfunction, Not Run	Not Run	This contains the status of the high voltage test for the shared high side driver circuit. The high side driver is output from the computer that supplies the voltage to the component.
High Side Driver 2 Circuit Low Voltage Test Status	OK, Malfunction, Not Run	Not Run	This contains the status of the low voltage test for the shared high side driver circuit. The high side driver is output from the computer that supplies the voltage to the component.
High Side Driver 2 Circuit Open Test Status	OK, Malfunction, Not Run	Not Run	This contains the status of the open test for the shared high side driver circuit. The high side driver is output from the computer that supplies the voltage to the component.
Hybrid Transmission Mode	Park/Neutral, Single Electric Motor Dual Electric Motors Single Electric Motor and ICE Dual Electric Motors and ICE, Invalid	Park/Neutral	The actual hybrid transmission mode as detected by the hybrid control module such as Park/Neutral, Single Electric Motor Dual Electric Motors, Single Electric Motor and ICE, Dual Electric Motors and ICE
Hybrid Transmission Mode Command	Park/Neutral, Single Electric Motor Dual Electric Motors Single Electric Motor and ICE Dual Electric Motors and ICE, Invalid	Park/Neutral	This parameter displays the hybrid transmission mode command as sent by the hybrid control module such as Park/Neutral, Single Electric Motor Dual Electric Motors, Single Electric Motor and ICE, Dual Electric Motors and ICE
Ignition Voltage	Volts	14.2 V	This parameter displays the voltage available to the transmission control module on the ignition voltage circuit.
Internal Mode Switch	Park, Reverse, Neutral, Drive (Drive 3), Low (Drive 2), Invalid	Park	This switch indicates transmission range. This is a contact switch attached to the control valve body within the transmission. The 9 outputs from the switch indicate which position is selected by the transmission manual shaft.
Internal Mode Switch A/B/C/P	High / Low	Low/High/High/Low	This displays the position of each internal mode switch state. A/B/C/P are identification for the 4 switches.
Line Pressure Control Solenoid Valve Control Circuit High Voltage Test Status	OK, Malfunction, Not Run	OK	This parameter displays the short to power (high voltage) test status of the control circuit for Line Pressure Solenoid Valve (electro-magnetic valve that can control the flow of fluid in a linear way.) which controls the overall hydraulic pressure of an automatic transmission.
Line Pressure Control Solenoid Valve Control Circuit Low Voltage Test Status	OK, Malfunction, Not Run	OK	This parameter displays the short to ground (Low voltage) test status of the control circuit for the Line Pressure Solenoid Valve (electro-magnetic valve that can control the flow of fluid in a linear way.) which controls the overall hydraulic pressure of an automatic transmission.
Line Pressure Control Solenoid Valve Performance Test Status	OK, Malfunction, Not Run	OK	This parameter displays the performance test status of the Line Pressure Solenoid Valve (electro-magnetic valve that can control the flow of fluid in a linear way.) which controls the overall hydraulic pressure of an automatic transmission.
Line Pressure Control Solenoid Valve Pressure Command	kPa (PSI)	10.7 PSI	This parameter displays the serial data command to control the pressure control solenoid for the main supply line.
Malfunction Counter	Counts	0	This parameter displays the Counts of the number of malfunction occurrences.
Not Run Counter	Counts	0	This parameter displays the counts of the number of situations in which a specific DTC test condition could not be executed to its end.
OSS Supply Voltage	OK, Out of Range	OK	This parameter displays the regulated transmission output shaft speed supply voltage is OK or outside of the normal operating range. Measurements are made by transmission control module.
Output Shaft Direction	Forward/Reverse/Unknown	Unknown	This Parameter indicates the direction of a transmission output shaft rotation. The transmission output shaft delivers rotating torque to the drive axles, enabling movement of the vehicle.
Output Speed Sensor Circuit	RPM	0 RPM	This parameter displays the RPM of the output from the transmission to the drive wheels.
Pass Counter	Counts	Varies	This parameter displays the counts of situations in which a specific DTC test condition was successfully executed.
Pressure Control Solenoid Valve 2 Control Circuit High Voltage Test Status	OK, Malfunction, Not Run	OK	This parameter displays the status of the transmission control module test which is testing for high voltage on the pressure control solenoid valve control circuit.
Pressure Control Solenoid Valve 2 Control Circuit Low Voltage Test Status	OK, Malfunction, Not Run	OK	This parameter displays the status of the transmission control module test which is testing for low voltage on the pressure control solenoid valve 2 control circuit.
Pressure Control Solenoid Valve 2 Performance Test Status	OK, Malfunction, Not Run	OK	This parameter displays the status of the transmission control module test of the pressure control solenoid valve 2 functionality.
Pressure Control Solenoid Valve 2 Pressure Command	kPa (PSI)	0 psi	This parameter displays the command in kPa of the transmission control module to the pressure control solenoid valve 2.
Pressure Control Solenoid Valve 3 Control Circuit High Voltage Test Status	OK, Malfunction, Not Run	OK	This parameter displays the status of the transmission control module test which is testing for high voltage on the pressure control solenoid valve 3 control circuit.
Pressure Control Solenoid Valve 3 Control Circuit Low Voltage Test Status	OK, Malfunction, Not Run	OK	This parameter displays the status of the transmission control module test which is testing for low voltage on the pressure control solenoid valve 3 control circuit.
Pressure Control Solenoid Valve 3 Performance Test Status	OK, Malfunction, Not Run	OK	This parameter displays the status of the transmission control module test of the pressure control solenoid valve 3 functionality.
Pressure Control Solenoid Valve 3 Pressure Command	kPa (PSI)	0 psi	This parameter displays the command in kPa of the transmission control module to the pressure control solenoid valve 3.
Pressure Control Solenoid Valve 4 Control Circuit High Voltage Test Status	OK, Malfunction, Not Run	OK	This parameter displays the status of the transmission control module test which is testing for high voltage on the pressure control solenoid valve 4 control circuit.
Pressure Control Solenoid Valve 4 Control Circuit Low Voltage Test Status	OK, Malfunction, Not Run	OK	This parameter displays the status of the transmission control module test which is testing for low voltage on the pressure control solenoid valve 4 control circuit.
Pressure Control Solenoid Valve 4 Performance Test Status	OK, Malfunction, Not Run	OK	This parameter displays the status of the transmission control module test of the pressure control solenoid valve 4 functionality.
Pressure Control Solenoid Valve 4 Pressure Command	kPa (PSI)	2000 PSI	This parameter displays the command in kPa of the transmission control module to the pressure control solenoid valve 4.
Pressure Control Solenoid Valve 5 Control Circuit High Voltage Test Status	OK, Malfunction, Not Run	OK	This parameter displays the status of the transmission control module test which is testing for high voltage on the pressure control solenoid valve 5 control circuit.
Pressure Control Solenoid Valve 5 Control Circuit Low Voltage Test Status	OK, Malfunction, Not Run	OK	This parameter displays the status of the transmission control module test which is testing for low voltage on the pressure control solenoid valve 5 control circuit.
Pressure Control Solenoid Valve 5 Performance Test Status	OK, Malfunction, Not Run	OK	This parameter displays the status of the transmission control module test of the pressure control solenoid valve 5 functionality.
Pressure Control Solenoid Valve 5 Pressure Command	kPa (PSI)	0.0 psi	This parameter displays the command in kPa of the transmission control module to the pressure control solenoid valve 5.
Replicated Transmission OSS Circuit Open Test Status	OK, Malfunction, Not Run	OK	This parameter displays the status of the transmission control module test which is testing for an open in the transmission output speed circuit. Replicated Transmission Output Shaft Speed is a circuit from the transmission control module to the ECM whose signal has been reproduced (replicated) from the Transmission Output Speed Signal circuit.
Replicated Transmission OSS Signal	On/Off	Off	This parameter displays the Replicated Transmission Output Shaft Speed (Replicated TOS) received from the Transmission Control Module. Replicated Transmission Output Shaft Speed is a circuit from the transmission control module to the ECM whose signal has been reproduced (replicated) from the Transmission Output Speed Signal circuit to the ECM.
Shift Solenoid Valve 1	On / Off	On	This parameter displays the command of the transmission control module to the shift solenoid valve 1.
Shift Solenoid Valve 1 Control Circuit High Voltage Test Status	OK, Malfunction, Not Run	OK	This parameter displays the status of the transmission control module test which is testing for high voltage on the shift solenoid valve 1 control circuit.
Shift Solenoid Valve 1 Control Circuit Low Voltage Test Status	OK, Malfunction, Not Run	OK	This parameter displays the status of the transmission control module test which is testing for low voltage on the shift solenoid valve 1 control circuit.
Shift Solenoid Valve 1 Control Circuit Open Test Status	OK, Malfunction, Not Run	OK	This parameter displays the status of the transmission control module test for an open in the shift solenoid valve 1 circuit.
Shift Solenoid Valve 2	On / Off	Off	This parameter displays the command of the transmission control module to the shift solenoid valve 2.
Shift Solenoid Valve 2 Control Circuit High Voltage Test Status	OK, Malfunction, Not Run	OK	This parameter displays the status of the transmission control module test which is testing for high voltage on the shift solenoid valve 2 control circuit.
Shift Solenoid Valve 2 Control Circuit Low Voltage Test Status	OK, Malfunction, Not Run	OK	This parameter displays the status of the transmission control module test which is testing for low voltage on the shift solenoid valve 2 control circuit.
Shift Solenoid Valve 2 Control Circuit Open Test Status	OK, Malfunction, Not Run	OK	This parameter displays the status of the transmission control module test for an open in the shift solenoid valve 2 circuit.
TCM Temperature	°C (°F)	74°C (165°F)	This parameter displays the temperature of the Transmission Control Module.
Transmission Fluid Pressure Switch 1	High / Low	High	This parameter displays the status of the transmission fluid pressure switch 1. An active pressure switch indicates that the associated clutch has been exhausted while an inactive pressure switch indicates that pressure is applied to the associated clutch.
Transmission Fluid Pressure Switch 3	High / Low	High	This parameter displays the status of the transmission fluid pressure switch 3. An active pressure switch indicates that the associated clutch has been exhausted while an inactive pressure switch indicates that pressure is applied to the associated clutch.
Transmission Fluid Pressure Switch 4	High / Low	Low	This parameter displays the status of the transmission fluid pressure switch 4. An active pressure switch indicates that the associated clutch has been exhausted while an inactive pressure switch indicates that pressure is applied to the associated clutch.
Transmission Fluid Pressure Switch 5	High / Low	High	This parameter displays the status of the transmission fluid pressure switch 5. An active pressure switch indicates that the associated clutch has been exhausted while an inactive pressure switch indicates that pressure is applied to the associated clutch.
Transmission Fluid Temperature	°C (°F)	69°C (156°F)	This parameter displays the temperature of the transmission fluid temperature.
Transmission ISS	RPM	1400 RPM	This parameter displays the rotational speed of the transmission input shaft. The scan tool displays input shaft speed is revolutions per minute (RPM).
Transmission OSS	RPM	0	This parameter measures the rotational speed of the transmission output shaft expressed as RPM.
Vehicle Speed	km/h (MPH)	0	This parameter displays the rate of vehicle movement in km/h (MPH).
Warm-ups Since DTC Cleared	Counts	Varies	This parameter displays the number of OBD defined warm-up cycles since the last time codes were cleared with a scan tool or, when applicable, with a battery disconnect. A warm up means that the engine started from a cold start condition (which is some calibrated value which is usually around 70 or 80°F) and warms to operating temperature in a single key cycle.
Warm-Ups without Emission Malfunctions	Counts	Varies	The scan tool displays a range of 0-255. This parameter counts the number of warm up cycles without an emission fault present. The counter increments to 255 and rolls back to 0 unless a fault occurs. If a fault occurs, the counter reverts back to 0 until the fault is corrected. Clearing the information with a scan tool or a loss of power to the PCM also resets the counter to 0. The scan tool displays counts. This display indicates the number of warm-up cycles without a emission failure. A warm up means that the engine started from a cold start condition (which is some calibrated value which is usually around 70 or 80°F) and warms to operating temperature in a single key cycle.
Warm-Ups without Non-Emission Malfunctions	Counts	Varies	The scan tool displays a range of 0-255. This parameter counts the number of warm up cycles without a non-emission fault present. The counter increments to 255 and rolls back to 0 unless a fault occurs. If a fault occurs, the counter reverts back to 0 until the fault is corrected. Clearing information with a scan tool or a loss of power to the PCM also resets the counter to 0. A warm up means that the engine started from a cold start condition (which is some calibrated value which is usually around 70 or 80°F) and warms to operating temperature in a single key cycle.

Scan Tool Output Controls

Output Control	Description
Shift Solenoid 1 Shift Solenoid 2	The TCM commands Shift Solenoid 1 and Shift Solenoid 2 ON and OFF. When the vehicle is ON, and the engine is OFF, there are no limits to this control. The solenoid remains On until commanded OFF, and vice versa. When the output control is exited, the solenoid state is determined by the TCM. When the engine is running, the following control limits apply: If the engine is running, the message "Engine Running" appears on the scan tool display.
Line PC Solenoid	The scan tool is used to request pressure in increments of 207 kPa (30 psi) from 0-1862 kPa (0-270 psi). The TCM will then command the solenoid to achieve the requested pressure. When the vehicle is in Service Mode, the pressure request may be controlled within calibrated limits. There are no limits to the output control when the engine is OFF. When the engine is running, the following control limits apply: When the transmission range is Park or Neutral, the pressure request may be controlled within calibrated limits. The engine speed must be less than 1, 500 RPM. If the engine speed is greater than 1, 500 RPM, the message "TR in park/neutral and engine speed over 1, 500 RPM" appears on the scan tool display. When the transmission range is not Park or Neutral, the requested pressure can only be controlled equal to or greater than the pressure determined by the TCM. The TCM does not allow a pressure to be selected that may cause damage to the transmission. If the requested pressure is less than allowed by the TCM, the message "Requested pressure for the Line PC Solenoid is too low" appears on the scan tool display. Transmission range DTCs must not be active. If a transmission range DTC is active, the message "Engine running with transmission DTC present" appears on the scan tool display.
PC Solenoid 2 PC Solenoid 3 PC Solenoid 4 PC Solenoid 5	The TCM commands the pressure control solenoids in order to apply and release the clutches. The TCM commands the pressure control solenoids. The solenoid remains ON until commanded OFF, and vice versa. When the output control is exited, the solenoid state is determined by the TCM. When the vehicle is in Service Mode, there are no limits to this control. The solenoid remains ON until commanded OFF, and vice versa. When the output control is exited, the solenoid state is determined by the TCM. When the engine is running, the following control limits apply: If the engine is running, the message "Engine Running" appears on the scan tool display. Transmission range DTCs must not be active. If a transmission range DTC is active, the message "Engine running with transmission DTC present" appears on the scan tool display.