Transmission Control Module Scan Tool Information (CVT)
WARNING: This page is about a different car, the 2014 Chevrolet Spark. However, it is still accessible from the selected car via links, so may be relevant.
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 components.
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 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. | |||
| Actual Line Pressure Control Solenoid Valve Current | Varies | mA | This parameter displays the actual current being used by the Line Pressure Solenoid Valve. The Line Pressure Control Solenoid Valve is also known as the Pressure Control Solenoid 1 Valve. The scan tool displays current flow in milliamperes (mA). A reading of 0 mA, no current flowing, indicates low line pressure. A reading of 1000 mA (1.000 ampere), high current flow, indicates high pressure. |
| Actual Pressure Control Solenoid Valve 2 Current | Varies | mA | This parameter displays the actual current being used by the Pressure Control Solenoid 2 Valve. The scan tool displays current flow in milliamperes (mA). A reading of 0 mA, no current flowing, indicates low line pressure. A reading of 1000 mA (1.000 ampere), high current flow, indicates high pressure. |
| Actual Pressure Control Solenoid Valve 3 Current | Varies | mA | This parameter displays the actual current being used by the Pressure Control Solenoid 3 Valve. The scan tool displays current flow in milliamperes (mA). A reading of 0 mA, no current flowing, indicates low line pressure. A reading of 1000 mA (1.000 ampere), high current flow, indicates high pressure. |
| Actual Pressure Control Solenoid Valve 4 Current | Varies | mA | This parameter displays the actual current being used by the Pressure Control Solenoid 4 Valve. The scan tool displays current flow in milliamperes (mA). A reading of 0 mA, no current flowing, indicates low line pressure. A reading of 1000 mA (1.000 ampere), high current flow, indicates high pressure. |
| Actual TCC Pressure Control Solenoid Valve Current | Varies | mA | This parameter displays the actual current being used by the Torque Convertor Clutch (TCC) Pressure Control Solenoid Valve. The scan tool displays current flow in milliamperes (mA). A reading of 0 mA, no current flowing, indicates low line pressure. A reading of 1000 mA (1.000 ampere), high current flow, indicates high pressure. |
| Brake Pedal Switch | Released | Applied/Released | This parameter displays the status of the brake switch circuit input. Applied indicates a zero voltage input, brake pedal applied. Released indicates a voltage input, brake pedal released. The scan tool displays Applied or Released. |
| Calculated Throttle Position | Varies | % | This parameter displays a calculated value based off accelerator pedal position and actual throttle position. It represents the driver's intended request for torque or acceleration. The range is 0-100%, where 0% represents an idle or coast request and 100% represents a request for wide open throttle (WOT). |
| Desired Pressure Control Solenoid Valve 2 Current | Varies | mA | This parameter displays the current that the transmission control module (TCM) is commanding be sent to the Pressure Control Solenoid 2 Valve. The scan tool displays current flow in milliamperes (mA). A reading of 0 mA, no current flowing, indicates low line pressure. A reading of 1000 mA (1.000 ampere), high current flow, indicates high pressure. |
| Desired Pressure Control Solenoid Valve 3 Current | Varies | mA | This parameter displays the current that the transmission control module (TCM) is commanding be sent to the Pressure Control Solenoid 3 Valve. The scan tool displays current flow in milliamperes (mA). A reading of 0 mA, no current flowing, indicates low line pressure. A reading of 1000 mA (1.000 ampere), high current flow, indicates high pressure. |
| Desired Pressure Control Solenoid Valve 4 Current | Varies | mA | This parameter displays the current that the transmission control module (TCM) is commanding be sent to the Pressure Control Solenoid 4 Valve. The scan tool displays current flow in milliamperes (mA). A reading of 0 mA, no current flowing, indicates low line pressure. A reading of 1000 mA (1.000 ampere), high current flow, indicates high pressure. |
| Desired TCC Pressure Control Solenoid Valve Current | Varies | mA | This parameter displays the current that the transmission control module (TCM) is commanding be sent to the TCC Pressure Control Solenoid Valve. The scan tool displays current flow in milliamperes (mA). A reading of 0 mA, no current flowing, indicates low line pressure. A reading of 1000 mA (1.000 ampere), high current flow, indicates high pressure. |
| Engine Speed | Varies | RPM | This parameter displays the rotational speed of the engine expressed as revolutions per minute. This parameter value is determined by the engine control module and communicated to the TCM through the High Speed GMLAN Serial Data link. |
| Engine Torque | Varies | (lb ft) | This parameter displays the estimated amount of torque that is being delivered from the engine. The ECM calculates this value based on engine load, throttle position, mass air flow and other engine inputs. The ECM communicates this value to the TCM through the High Speed GMLAN Serial Data link. |
| Gear Ratio | Varies | Ratio | This parameter displays the actual transmission gear ratio. The scan tool displays the gear ratio calculated from the automatic transmission (AT) input speed sensor (ISS) and the automatic transmission (AT) output speed sensor (OSS) inputs. |
| Ignition Voltage | 9-19 | Volts | This parameter displays the system voltage measured by the transmission control module (TCM) at the TCM ignition voltage input circuit. |
| Line Pressure Solenoid Valve Current Command | Varies | mA | This parameter displays the current the transmission control module (TCM) is commanding be sent to the Line Pressure Control Solenoid Valve. The scan tool displays current flow in milliamperes (mA). A reading of 0 mA, no current flowing, indicates low line pressure. A reading of 1000 mA (1.000 ampere), high current flow, indicates high pressure. The Line Pressure Solenoid Valve is also known as the Line Pressure Control Solenoid Valve or the Pressure Control Solenoid Valve 1. |
| Line Pressure Control Solenoid Valve Control Circuit High Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether an open/short to voltage exists in the line pressure control valve control circuit. The scan tool displays OK, Malfunction or Not Run. The Line Pressure Control Solenoid Valve is also known as the Pressure Control Solenoid Valve 1. |
| Line Pressure Control Solenoid Valve Control Circuit Low Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a short to ground exists in the line pressure control valve control circuit. The scan tool displays OK, Malfunction or Not Run. The Line Pressure Control Solenoid Valve is also known as the Pressure Control Solenoid Valve 1. |
| Pressure Control Solenoid Valve 1 | Off | ON/OFF | This parameter displays the current state of the pressure control solenoid valve 1. The Pressure Control Solenoid Valve 1 is also known as the Line Pressure Control Solenoid Valve. |
| Pressure Control Solenoid Valve 2 | Off | ON/OFF | This parameter displays the current state of the pressure control solenoid valve 2. |
| Pressure Control Solenoid Valve 2 Control Circuit High Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether an open/short to voltage exists in the pressure control solenoid valve 2 control circuit. The scan tool displays OK, Malfunction or Not Run. |
| Pressure Control Solenoid Valve 2 Control Circuit Low Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a short to ground exists in the pressure control solenoid valve 2 control circuit. The scan tool displays OK, Malfunction or Not Run. |
| Pressure Control Solenoid Valve 3 | Off | ON/OFF | This parameter displays the current state of the pressure control solenoid valve 3. |
| Pressure Control Solenoid Valve 3 Control Circuit High Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether an open/short to voltage exists in the pressure control solenoid valve 3 control circuit. The scan tool displays OK, Malfunction or Not Run. |
| Pressure Control Solenoid Valve 3 Control Circuit Low Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a short to ground exists in the pressure control solenoid valve 3 control circuit. The scan tool displays OK, Malfunction or Not Run. |
| Pressure Control Solenoid Valve 4 | Off | ON/OFF | This parameter displays the current state of the pressure control solenoid valve 4. |
| Pressure Control Solenoid Valve 4 Control Circuit High Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether an open/short to voltage exists in the pressure control solenoid valve 4 control circuit. The scan tool displays OK, Malfunction or Not Run. |
| Pressure Control Solenoid Valve 4 Control Circuit Low Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a short to ground exists in the pressure control solenoid valve 4 control circuit. The scan tool displays OK, Malfunction or Not Run. |
| Primary Pulley Speed | Varies | RPM | This parameter displays the rotational speed of the Primary Pulley expressed as revolutions per minute. This parameter value is determined by the Primary Pulley/Input Speed Sensor. |
| Secondary Pulley Pressure Sensor | Varies | V | This parameter displays the voltage sent to the secondary pulley pressure sensor. |
| Secondary Pulley Pressure | Varies | MPa (psi) | This parameter displays the actual pressure at the secondary pulley. |
| Secondary Pulley Speed | Varies | RPM | This parameter displays the rotational speed of the Secondary Pulley expressed as revolutions per minute. This parameter value is determined by the Secondary Pulley/Intermediate Shaft Speed Sensor. |
| TCC Pressure Control Solenoid Valve Pressure Command | Varies | MPa (psi) | This parameter displays the actual pressure at the TCC Pressure Control Solenoid Valve. |
| TCC Slip Speed | Varies | RPM | This parameter displays the amount of torque converter clutch (TCC) slip between the engine and the transmission input shaft. 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 Pressure Switch 1 | High/Low | High/Low | This parameter indicates the state of the transmission fluid pressure switch control circuit. This parameter indicates High when high current (low pressure) is commanded and Low when low current (high pressure) is requested. The Transmission Fluid Pressure Switch is also known as the Transmission Fluid Pressure Switch 1. |
| Transmission Fluid Pressure Switch 3 | High/Low | High/Low | This parameter indicates the state of the transmission fluid pressure switch 3 circuit. This parameter indicates High when high current (low pressure) is commanded and Low when low current (high pressure) is requested. The Transmission Fluid Pressure Switch 3 is also known as the High Clutch Pressure Switch or the Secondary Pulley Pressure Sensor. |
| Transmission Fluid Temperature | Varies | °C (°F) | This parameter displays the input signal of the transmission fluid temperature sensor. Transmission fluid temperature is high 151°C (304°F) when signal voltage is low, 0 V and transmission fluid temperature is low -40°C (-40°F) when signal voltage is high, 2.5 V. |
| Transmission ISS | Varies | RPM | This parameter displays the rotational speed of the transmission input shaft/primary pulley. The scan tool displays input shaft speed is revolutions per minute (RPM). |
| Transmission OSS | Varies | RPM | This parameter displays the rotational speed of the transmission output shaft/final gear expressed as revolutions per minute. |
| Transmission Range Switch | Park | Park, Reverse, Neutral, Drive, Low or Invalid | This parameter displays the current position of the transmission range switch. |
| Transmission Range Switch A/B/C/P | High, High, High, Low | High/Low | This parameter displays the status of the four A/B/C/P inputs from the automatic transmission range switch. HI indicates an ignition voltage signal and LOW indicates a 0 voltage signal. The scan tool will display High or Low for each input. |
| Vehicle Speed Sensor | Varies | km/h (MPH) | This parameter displays the speed at which the vehicle is traveling as kilometers per hour (km/h) or miles per hour (MPH). The transmission control module (TCM) calculates vehicle speed based on the input signal from the vehicle/output shaft speed sensor. |
Scan Tool Output Controls
| Output Control | Description |
|---|---|
| Line Pressure Control Solenoid Valve | This function allows control of the current being sent by the transmission control module to the Line Pressure Control Solenoid Valve and measured by the "Actual Line Pressure Control Solenoid Valve Current" parameter. As the amperage increases, the line pressure decreases. As the amperage decreases, the line pressure increases. The amperage range is 0.00-1.00 A and may be commanded in 0.10 A increments.
NOTE:
The "Line Pressure Solenoid Valve Current Command" will not change. Functional requirements:
For hardware protection: The system will remain in the commanded state for only 5 seconds or until cancelled or changed by the scan tool. |
| Pressure Control Solenoid Valve | This function allows control of the current being sent by the transmission control module to the Pressure Control Solenoid Valve and measured by the "Actual Pressure Control Solenoid Valve 2 Current" parameter. As the amperage increases, the line pressure decreases. As the amperage decreases, the line pressure increases. The amperage range is 0.00-1.00 A and may be commanded in 0.10 A increments.
NOTE:
The "Desired Pressure Control Solenoid Valve 2 Current" will not change. Functional requirements:
For hardware protection: The system will remain in the commanded state for only 5 seconds or until cancelled or changed by the scan tool. |
| Torque Converter Clutch (TCC) Pressure Control Solenoid Valve | This function allows control of the current being sent by the transmission control module to the Torque Converter Clutch (TCC) Pressure Control Solenoid Valve and measured by the "Actual Torque Converter Clutch (TCC) Pressure Control Solenoid Valve 2 Current" parameter. As the amperage increases, the line pressure increases. As the amperage decreases, the line pressure decreases. The amperage range is 0.00-1.00 A and may be commanded in 0.10 A increments.
NOTE:
The "Desired Torque Converter Clutch (TCC) Pressure Control Solenoid Valve Current" will not change. Functional requirements:
For hardware protection: The system will remain in the commanded state for only 5 seconds or until cancelled or changed by the scan tool. |
| Transmission Adaptive Pressure Reset | The TCM clears or resets, the transmission adapt pressure (TAP) cells to the original base value. There are no limits to using this output control. It may be performed with the engine running or when the ignition is ON and the engine is OFF. The Transmission Adaptive Pressure Reset procedure is used to synchronize the transmission control module with the ROM assembly in transmission. The Transmission Adaptive Pressure Reset procedure must be performed whenever one of the following repairs have been made to the vehicle:
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