K71 Transmission Control Module: Scan Tool Information (4EL70)
The Transmission Control Module Scan Tool Data List contains all transmission related parameters that are available on the scan tool. 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.
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 value described below, refer to Symptoms - Automatic Transmission . If A DTC is set refer to Diagnostic Trouble Code (DTC) List - Vehicle .
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: Vehicle at operating temperature, closed throttle, transmission in park, accessories OFF, brake pedal not applied. | |||
| Brake Pedal Position Circuit Signal | Pedal Released | Released | This string refers to the circuit that monitors the relative position of the brake pedal as it travels from a position where it is fully depressed to a position where the driver's foot is completely off the pedal or vice versa. A signal is an electrical quantity or effect, as current, voltage or electromagnetic waves that can be varied in such a way as to convey information. The term "circuit" refers to the path of electricity. |
| Calculated Clutch 1 Torque | Varies | N.m | 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 | Varies | N.m | 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 | Varies | N.m | 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 Clutch 4 Torque | Varies | N.m | The transmission control module calculates the torque applied to each clutch in the transmission. This parameter displays the calculated torque value for Clutch 4. |
| Calculated Line Pressure | Varies | kPa | This parameter indicates the expected real line pressure after accounting for pump loss factors. |
| Calculated Throttle Position | Varies | % | 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, PTO, 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 Fill Time | Varies | Seconds | The time that is need to fill the clutch with fluid. |
| Clutch 1 Maximum Energy | Varies | Joules | This parameter displays the maximum energy in joules the clutch is capable of delivering. |
| Clutch 1 Status | Varies | Engaged / Disengaged | 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 2 Fill Time | Varies | Seconds | The time that is need to fill the clutch with fluid. |
| Clutch 2 Maximum Energy | Varies | Joules | This parameter displays the maximum energy in joules the clutch is capable of delivering. |
| Clutch 2 Status | Varies | Engaged/Disengaged | 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 3 Fill Time | Varies | Seconds | The time that is need to fill the clutch with fluid. |
| Clutch 3 Maximum Energy | Varies | Joules | This parameter displays the maximum energy in joules the clutch is capable of delivering. |
| Clutch 3 Status | Varies | Engaged / Disengaged | 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 4 Fill Time | Varies | Seconds | The time that is need to fill the clutch with fluid. |
| Clutch 4 Maximum Energy | Varies | Joules | This parameter displays the maximum energy in joules the clutch is capable of delivering. |
| Clutch 4 Status | Varies | Engaged / Disengaged | 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. |
| Driver Requested Axle Torque | Varies | N.m | 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 | Varies | °C (°F) | The engine coolant temperature (ECT) sensor is a variable resistance thermistor that changes resistance as the engine's coolant temperature changes. The sensor's output is monitored by the engine computer to regulate various ignition, fuel and emission control functions and to turn the radiator-cooling fan on and off as needed. |
| Engine Speed | Varies | RPM | Indicates the speed of the engine in RPM. |
| High Side Driver 1 Circuit High Voltage Test Status | Varies | 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 computer that supplies the voltage to the component. |
| High Side Driver 1 Circuit Low Voltage Test Status | Varies | 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 component. |
| High Side Driver 1 Circuit Open Test Status | Varies | 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 component. |
| High Side Driver 1 Command | Varies | Disabled / Enable | This contains the commanded state of the shared high side driver 1 output. A shared high side driver serves as a controlled actuator supply voltage for devices with individual low side control. The high side driver is output from the computer that supplies the voltage to the component. |
| High Side Driver 2 Circuit High Voltage Test Status | Varies | 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 computer that supplies the voltage to the component. |
| High Side Driver 2 Circuit Low Voltage Test Status | Varies | 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 component. |
| High Side Driver 2 Circuit Open Test Status | Varies | 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 component. |
| High Side Driver 2 Command | Varies | Disabled / Enable | This contains the commanded state of the shared high side driver 2 output. A shared high side driver serves as a controlled actuator supply voltage for devices with individual low side control. The high side driver is output from the computer that supplies the voltage to the component. |
| Hybrid/EV Transmission Mode | Park | Park/Neutral, Single Electric Motor Dual Electric Motors Single Electric Motor and ICE |
The actual hybrid transmission mode as detected by the hybrid control module such as: Park/Neutral, EV1, EV2, Gear 1/2/3/4 and Invalid. |
| Hybrid/EV Transmission Mode Command | Park | Park/Neutral, Single Electric Motor Dual Electric Motors Single Electric Motor and ICE |
The serial data command to change the hybrid transmission mode such as: Park/Neutral, EV1, EV2, Gear 1/2/3/4 and Invalid. |
| Ignition Voltage | Varies | Volts | This parameter displays the voltage available to the TCM on the ignition voltage circuit. |
| Internal Mode Switch | Varies | Park, Reverse, Neutral, Drive 1, Drive 2, Drive 3, Invalid | 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 | Varies | High/Low | This switch indicates the gear the transmission is in. A/B/C/P are identification for the 4 switches. |
| ISS/OSS Supply Voltage | Varies | Volts | Indicates the regulated transmission input shaft speed/output shaft speed supply voltage is outside of the normal operating range as specified in the operating specifications. Measurements are made by transmission control module internal components. |
| Line Pressure Control Solenoid Valve | Varies | Yes / No | Line pressure (hydraulic pressure within the fluid circuits of the transmission) in an automatic transmission is controlled via a line pressure control solenoid valve. |
| Line Pressure Control Solenoid Valve Control Circuit High Voltage Test Status | Varies | OK | Indicates 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 or gas 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 | Varies | OK | Indicates 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 or gas in a linear way) which controls the overall hydraulic pressure of an automatic transmission. |
| Line Pressure Control Solenoid Valve Control Circuit Open Test Status | Varies | OK | Indicates the open test status of the control circuit for the Line Pressure Solenoid Valve (electro-magnetic valve that can control the flow of fluid or gas in a linear way) which controls the overall hydraulic pressure of an automatic transmission. |
| Line Pressure Control Solenoid Valve Pressure Command | Varies | kPa | Serial data command to control the pressure control solenoid for the main supply line. |
| Output Shaft Direction | Varies | Forward / Reverse | This Parameter indicates the direction of a transmission output shaft rotation. The transmission output shaft delivers the power out of the transmission to drive shaft to the wheels on the rear axle, enabling movement of the vehicle. |
| Output Shaft Speed Sensor | Varies | RPM | This contains the transmission output speed (the speed at the output of the gear box) determined from the speed measured by the transmission output speed sensor (OSS). |
| Regenerative Braking On Demand | Varies | Active / Inactive None / Invalid |
Regeneration on Demand enables drivers to actively re-capture energy when slowing down, such as when approaching slower traffic or setting up for a tight turn. To engage Regeneration on Demand, the driver releases the accelerator pedal and pulls back on either the left or right steering-wheel paddle to begin regenerating electricity. When engaged, Regeneration on Demand provides vehicle deceleration that is more than what a typical vehicle experiences while coasting or when the transmission shifter is in the L position, providing control and dynamic performance characteristics similar to downshifting in a manual-transmission vehicle. The feature does not bring the vehicle to a complete stop. Releasing the paddle cancels the Regeneration on Demand request, allowing the vehicle to coast normally. The driver can engage and disengage Regeneration on Demand as desired and as traffic conditions allow. This PID displays the current state of the regeneration on demand switch. |
| Shift Solenoid Valve 1 Command | Varies | On / Off | Device which controls transmission fluid flow used to shift an automatic transmission. |
| Shift Solenoid Valve 1 Control Circuit High Voltage Test Status | Varies | OK | Indicates if the transmission control module has run a diagnostic circuit test and/or displays the present electrical condition of the circuit. |
| Shift Solenoid Valve 1 Control Circuit Low Voltage Test Status | Varies | OK | Indicates if the transmission control module has run a diagnostic circuit test and/or displays the present electrical condition of the circuit. |
| Shift Solenoid Valve 1 Control Circuit Open Test Status | Varies | OK | Indicates if the transmission control module has run a diagnostic circuit test and/or displays the present electrical condition of the circuit. |
| Transmission Control Solenoid Valve 2 | Varies | On / Off | This parameter displays the state of the transmission control solenoid. |
| Transmission Control Solenoid Valve 2 Control Circuit High Voltage Test Status | Varies | OK | Indicates if the transmission control module has run a diagnostic circuit test and/or displays the present electrical condition of the circuit. |
| Transmission Control Solenoid Valve 2 Control Circuit Low Voltage Test Status | Varies | OK | Indicates if the transmission control module has run a diagnostic circuit test and/or displays the present electrical condition of the circuit. |
| Transmission Control Solenoid Valve 2 Control Circuit Open Test Status | Varies | OK | Indicates if the transmission control module has run a diagnostic circuit test and/or displays the present electrical condition of the circuit. |
| Transmission Control Solenoid Valve 2 Pressure Command | Varies | kPa | Pressure command for solenoid valve 2 in kilopascals (kPa). |
| Transmission Control Solenoid Valve 3 | Varies | On / Off | This parameter displays the state of the transmission control solenoid. |
| Transmission Control Solenoid Valve 3 Control Circuit High Voltage Test Status | Varies | OK | Indicates if the transmission control module has run a diagnostic circuit test and/or displays the present electrical condition of the circuit. |
| Transmission Control Solenoid Valve 3 Control Circuit Low Voltage Test Status | Varies | OK | Indicates if the transmission control module has run a diagnostic circuit test and/or displays the present electrical condition of the circuit. |
| Transmission Control Solenoid Valve 3 Control Circuit Open Test Status | Varies | OK | Indicates if the transmission control module has run a diagnostic circuit test and/or displays the present electrical condition of the circuit. |
| Transmission Control Solenoid Valve 3 Pressure Command | Varies | kPa | Pressure command for solenoid valve 3 in kilopascals (kPa). |
| Transmission Control Solenoid Valve 4 | Varies | On / Off | This parameter displays the state of the transmission control solenoid. |
| Transmission Control Solenoid Valve 4 Control Circuit High Voltage Test Status | Varies | OK | Indicates if the transmission control module has run a diagnostic circuit test and/or displays the present electrical condition of the circuit. |
| Transmission Control Solenoid Valve 4 Control Circuit Low Voltage Test Status | Varies | OK | Indicates if the transmission control module has run a diagnostic circuit test and/or displays the present electrical condition of the circuit. |
| Transmission Control Solenoid Valve 4 Control Circuit Open Test Status | Varies | OK | Indicates if the transmission control module has run a diagnostic circuit test and/or displays the present electrical condition of the circuit. |
| Transmission Control Solenoid Valve 4 Pressure Command | Varies | kPa | Pressure command for solenoid valve 4 in kilopascals (kPa). |
| Transmission Control Solenoid Valve 5 | Varies | On / Off | This parameter displays the state of the transmission control solenoid. |
| Transmission Control Solenoid Valve 5 Control Circuit High Voltage Test Status | Varies | OK | Indicates if the transmission control module has run a diagnostic circuit test and/or displays the present electrical condition of the circuit. |
| Transmission Control Solenoid Valve 5 Control Circuit Low Voltage Test Status | Varies | OK | Indicates if the transmission control module has run a diagnostic circuit test and/or displays the present electrical condition of the circuit. |
| Transmission Control Solenoid Valve 5 Control Circuit Open Test Status | Varies | OK | Indicates if the transmission control module has run a diagnostic circuit test and/or displays the present electrical condition of the circuit. |
| Transmission Control Solenoid Valve 5 Pressure Command | Varies | kPa | Pressure command for solenoid valve 5 in kilopascals (kPa). |
| Transmission Control Solenoid Valve 6 | Varies | On / Off | This parameter displays the state of the transmission control solenoid. |
| Transmission Control Solenoid Valve 6 Control Circuit High Voltage Test Status | Varies | OK | Indicates if the transmission control module has run a diagnostic circuit test and/or displays the present electrical condition of the circuit. |
| Transmission Control Solenoid Valve 6 Control Circuit Low Voltage Test Status | Varies | OK | Indicates if the transmission control module has run a diagnostic circuit test and/or displays the present electrical condition of the circuit. |
| Transmission Control Solenoid Valve 6 Control Circuit Open Test Status | Varies | OK | Indicates if the transmission control module has run a diagnostic circuit test and/or displays the present electrical condition of the circuit. |
| Transmission Control Solenoid Valve 6 Pressure Command | Varies | kPa | Pressure command for solenoid valve 6 in kilopascals (kPa). |
| Transmission Fluid Temperature | Varies | °C (°F) | Indicates the temperature of the transmission fluid. |
| Transmission OSS | Varies | RPM | Indicates the rotational speed of the transmission output shaft in revolutions per minute. |
| Vehicle Speed Sensor | Varies | km/h | This is the sensor that measures vehicle speed. |
Scan Tool Output Control Functions
| Parameter | System State | Expected Value | Description |
|---|---|---|---|
| Line Pressure Control Solenoid Valve Pressure Command | Varies | Increase / Decrease | Serial data command to control the pressure control solenoid for the main supply line. |
| Pressure Control Solenoid Valve 2 Pressure Command | Varies | On / Off | Allow you to command the transmission solenoid 2 electrical current from 0-1.2 amps. |
| Pressure Control Solenoid Valve 3 Pressure Command | Varies | On / Off | Allow you to command the transmission solenoid 3 electrical current from 0-1.2 amps. |
| Pressure Control Solenoid Valve 4 Pressure Command | Varies | On / Off | Allow you to command the transmission solenoid 4 electrical current from 0-1.2 amps. |
| Pressure Control Solenoid Valve 5 Pressure Command | Varies | On / Off | Allow you to command the transmission solenoid 5 electrical current from 0-1.2 amps. |
| Pressure Control Solenoid Valve 6 Pressure Command | Varies | On / Off | Allow you to command the transmission solenoid 6 electrical current from 0-1.2 amps. |
| Shift Solenoid Valve 1 | Varies | On / Off | Allows you to command solenoid valve 1 OFF or ON. |
| Transmission Adaptive Pressure Reset | - | - | Serial data command to cause the transmission's learned (adaptive) pressure to reset to zero. The adaptive pressure is the pressure that the control module needs to compensate for any variable (tolerances) in the shift. |