K71 Transmission Control Module: Scan Tool Information (AF50-8)
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.
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 for diagnosis.
The scan tool values from a properly functioning transmission may be used for comparison with the transmission that is being diagnosed. The values below represent a typical display recorded from a properly functioning system/vehicle.
K71 Transmission Control ModuleScan Tool Parameters
| Parameter | Expected Value | Description |
|---|---|---|
Operating Conditions:
|
||
| Actual Pressure Control Solenoid Valve 1-6 Current |
|
Pressure control solenoid valve current as measured by the TCM on the feedback circuit. |
| Actual TCC Pressure Control Solenoid Valve Current | 98 mA | TCC pressure control solenoid valve current as measured by the TCM on the feedback circuit. |
| Barometric Pressure Signal Status | Valid | Barometric Pressure sensor is an input to the engine controller that reflects atmospheric pressure. |
| Brake Pedal Position Sensor | 0 % | Position of the brake pedal, as determined by the brake pedal position sensor. |
| Brake Pedal Position Sensor Signal | Valid | This parameter displays the status of the brake pedal position sensor broadcast message. |
| 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, 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). |
| Control Module Voltage Signal | 13.8 V | Displays the voltage that is currently available for the control module to function. A typical values will be whatever the current available battery voltage is (12-14v). |
| Current Gear | Park | This indicates the gear that is currently engaged. |
| Desired Pressure Control Solenoid Valve 1-6 Current |
|
The commanded current to the pressure control solenoid valve. |
| Desired TCC Pressure Control Solenoid Valve Current | 98 mA | The commanded current to the TCC pressure control solenoid valve. |
| Distance Since DTC Cleared | 0 km/h (0 MPH) | The distance traveled since the clear DTC function was performed. |
| Distance Since Torque Signal Invalid Message Received by TCM | 0 km/h (0 MPH) | Distance Since Torque Inaccurate Bit Received by TCM. |
| Driver Shift Control Mode | Inactive | Monitors the status of the manual shift mode switch. With this switch the driver can choose if the transmission shifts automatically or if the driver wants to do the shifting on his own manually with 2 other switches for up/down shifting. |
| Engine Control Module - Accelerator Pedal Position Signal | Valid | Accelerator Pedal Position signal (from the engine control module) is communicating the accelerator pedal position to any module that needs the information. |
| Engine Coolant Temperature | 96 °C (205 °F) | The temperature of the engine coolant (fluid used to cool a system by transferring heat away from one part to another). |
| Engine Coolant Temperature Signal | Valid | This parameter displays the status of the engine coolant temperature sensor broadcast message. |
| Engine Speed | 650 RPM | Indicates the speed of the engine in RPM. |
| Engine Speed Signal | Valid | This parameter displays the status of the crankshaft position sensor broadcast message. |
| Engine Torque | 7 Nm (5lb ft) | This parameter displays the engine torque based upon airflow through the engine and the torque losses due to spark retard and fuel shutoff. Since this is a steady state engine torque, it does not include the inertial component of engine torque. |
| Engine Torque Signal | Valid | This parameter displays the status of the engine torque broadcast message. |
| Fail-Safe Mode | Active | Failsafe is a mode of operation that is entered if an error has been detected. In Failsafe Mode, many functions are disabled a some have limited functionality. Similar to Limp Home Mode. |
| Gear Command | Park | This displays the current gear as commanded by the transmission control module. |
| Gear Ratio | 8.00:1 | Describes the relationship between the number of teeth on two gears that are meshed. Gear ratios are what allow a car to reach a high rate of speed or climb a steep hill. This parameter displays the gear ratio for the vehicle's final drive which refers to the rear axle, final gear set before the power reaches the rear wheels. |
| Ignition Accessory Signal | On | This indicates that the accessory hardwire input to the controller is active in applications using a specific type of power mode electrical architecture. This parameter displays the voltage available to the ECM on the ignition accessory signal circuit. |
| Ignition Cycles Since Torque Signal Invalid Message Received by TCM | 0 Counts | Ignition cycles since torque inaccurate bit received by the TCM. |
| Power Mode | Run | The state of the electrical system on the vehicle depending on the position of the ignition switch. This indicates the status of the ignition switch. |
| Pressure Control Solenoid Valve 1-6 |
|
TCM command for the individual Pressure Control Solenoid Valves. |
| Pressure Control Solenoid Valve 1-6 Control Circuit Low Voltage Test Status |
|
This parameter displays the results of the pressure control solenoid valve short to ground test. |
| Pressure Control Solenoid Valve 1-6 Control Circuit Open Test Status |
|
This parameter displays the results of the pressure control solenoid valve open circuit test. |
| Pressure Control Solenoid Valve 1-6 High Voltage Test Status |
|
This parameter displays the results of the pressure control solenoid valve high voltage test. |
| Shift Solenoid Valve 1 | On | Display the commanded status of the shift solenoid valve. |
| Shift Solenoid Valve 1 Control Circuit High Voltage Test Status | OK | This parameter displays the results of the shift solenoid valve high voltage test. |
| Shift Solenoid Valve 1 Control Circuit Low Voltage Test Status | OK | This parameter displays the results of the shift solenoid valve low voltage test. |
| Shift Solenoid Valve 1 Control Circuit Open Test Status | OK | This parameter displays the results of the shift solenoid valve open circuit test. |
| Shift Solenoid Valve 2 | Off | Display the commanded status of the shift solenoid valve. |
| Shift Solenoid Valve 2 Control Circuit High Voltage Test Status | OK | This parameter displays the results of the shift solenoid valve high voltage test. |
| Shift Solenoid Valve 2 Control Circuit Low Voltage Test Status | OK | This parameter displays the results of the shift solenoid valve low voltage test. |
| Shift Solenoid Valve 2 Control Circuit Open Test Status | OK | This parameter displays the results of the shift solenoid valve open circuit test. |
| TCC Pressure Control Solenoid Valve Control Circuit High Voltage Test Status | OK | This parameter displays the results of the TCC pressure control solenoid valve high voltage test. |
| TCC Pressure Control Solenoid Valve Control Circuit Low Voltage Test Status | OK | This parameter displays the results of the TCC pressure control solenoid valve low voltage test. |
| TCC PWM Control Circuit Status | Off | This parameter displays the PWM command of the TCC circuit. |
| TCC Release Pressure | No | This parameter displays the PWM command of the TCC circuit. |
| TCC Slip Speed | 60 RPM | This parameter displays the difference between transmission input speed and engine speed (slip). A negative value indicates that the engine speed is less than the input speed, deceleration. A positive value indicates that the engine speed is greater than the input speed, acceleration. A value of zero indicates that the engine speed is equal to the input speed, TCC applied. |
| Transmission Fluid Temperature | 41 °C (106 °F) | Indicates the temperature of the transmission fluid. |
| Transmission ISS | 530 RPM | ISS is input shaft speed. This parameter displays the rotational speed of the transmission input shaft expressed as RPM. |
| Transmission OSS | 0 RPM | OSS represents output shaft speed. This parameter measures the rotational speed of the transmission output shaft expressed as RPM. |
| Transmission Protection Mode | Active | This string indicates the transmission is in a mode to protect itself from destruction. The different states of this mode, represent different variations of the mode. |
| Transmission Range Switch | Park | Transmission Range Switch refers to the input to the controller that indicates what gear or shift selector position the driver has selected. |
| Transmission Shift Mode | 1 | Displays the current gear that the transmission is in. |
| Vehicle Distance Traveled During Drive Cycle | 0 km (0 mi) | This parameter displays the distance that the vehicle has traveled during the current drive cycle. |
| Vehicle Speed Sensor | 0 km/h (0 MPH) | This parameter displays vehicle speed. |
K71 Transmission Control ModuleScan Tool Control Functions
| Control Function | Description |
|---|---|
| Pressure Control Solenoid Valve | This control function is used to activate the individual pressure control solenoid valves. Activates the individual pressure control solenoid valves. |
| Shift Solenoid Valve | This control function is used to activate the individual shift solenoid valves. |
| Shift Transmission Gear | This control function is used to manually command a transmission gear change. |
| TCC Solenoid Valve | This control function is used to activate the TCC solenoid valve. |