Transmission Control Module Scan Tool Information (MR8)
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 | Expected Value | Description |
|---|---|---|
| This is a comprehensive list. Not all parameters listed are available for all applications. Operating Conditions:
|
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| Actual Auxiliary Gear Ratio | Varies | Display Status/Display Units: Varies This parameter displays the actual auxiliary gear ratio |
| Actual Input/Output Speed Ratio | 750:1 | Display Status/Display Units: Varies This parameter displays the actual ratio between the input and output speed sensors |
| Actual Line Pressure Control Solenoid Valve Current | Engine idling.=906 mA | Display Status/Display Units: 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. |
| Ignition - On / Vehicle - In Service Mode= 1000 mA | ||
| Actual Pressure Control Solenoid Valve 2 Current | Engine idling.= 889 mA | Display Status/Display Units: 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. |
| Ignition - On / Vehicle - In Service Mode= 1000 mA | ||
| Actual Pressure Control Solenoid Valve 3 Current | 3 mA | Display Status/Display Units: 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 | 1000 mA | Display Status/Display Units: 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 Pulley Gear-Ratio | Varies | Display Status/Display Units: Varies |
| Actual TCC Pressure Control Solenoid Valve Current | 1000 mA | Display Status/Display Units: 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. |
| Auxiliary Transmission Fluid Pump Duty Cycle | Varies | Display Status/Display Units: X% This parameter displays the PWM commanded duty cycle of the Auxiliary Transmission Fluid Pump. The scan tool displays PWM commanded duty cycle in %. A reading of 0 % indicates the pressure is acceptable and no additional pressure required. A reading of 100 % indicates the pressure is low and a lot of additional pressure is required. |
| Auxiliary Transmission Fluid Pump Command | - | Display Status/Display Units: On/Off |
| Auxiliary Transmission Pump Control Circuit High Voltage Test Status | OK | Display Status/Display Units: OK/Malfunction/Not Run This parameter displays whether a short to voltage exists in the Auxiliary Transmission Pump Control Circuit. |
| Auxiliary Transmission Pump Control Circuit Low Voltage Test Status | OK | Display Status/Display Units: OK/Malfunction/Not Run This parameter displays whether a short to ground exists in the Auxiliary Transmission Pump Control Circuit. |
| Auxiliary Transmission Pump Control Circuit Open Test Status | OK | Display Status/Display Units: OK/Malfunction/Not Run This parameter displays whether an open exists in the Auxiliary Transmission Pump Control Circuit. |
| Auxiliary Transmission Pump Fault Status | OK | Display Status/Display Units: OK/Malfunction/Not Run |
| Auxiliary Transmission Fluid Pump Relay Command | Off | Display Status/Display Units: On/Off This parameter displays: The current state of the Auxiliary Transmission Fluid Pump Relay Control Circuit |
| Auxiliary Transmission Fluid Pump Relay Control Circuit High Voltage Test Status | With RPO KL9 = OK |
Display Status/Display Units: OK/Malfunction/Not Run This parameter displays whether a Short to Voltage exists in the Auxiliary Transmission Fluid Pump Relay Control Circuit |
| Without RPO KL9=Malfunction | ||
| Auxiliary Transmission Fluid Pump Relay Control Circuit Low Voltage Test Status | With RPO KL9 = OK |
Display Status/Display Units: OK/Malfunction/Not Run This parameter displays whether a short to ground exists in the Auxiliary Transmission Fluid Pump Relay Control Circuit. |
| Without RPO KL9=Malfunction | ||
| Auxiliary Transmission Fluid Pump Relay Control Circuit Open Test Status | With RPO KL9 = OK |
Display Status/Display Units: OK/Malfunction/Not Run This parameter displays whether an open exists in the pressure Auxiliary Transmission Fluid Pump Relay Control Circuit. |
| Without RPO KL9=Malfunction | ||
| Brake Pedal Switch | Released | Display Status/Display Units: 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 | 0% | Display Status/Display Units: % 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 Auxiliary Gear Ratio | Varies | Display Status/Display Units: Varies |
| Desired Input/Output Speed Ratio | Varies | Display Status/Display Units: Varies |
| Desired Pressure Control Solenoid Valve 2 Current | Engine idling.= 889 mA | Display Status/Display Units: 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. |
| Ignition - On / Vehicle - In Service Mode= 1000 mA | ||
| Desired Pressure Control Solenoid Valve 3 Current | 0 mA | Display Status/Display Units: 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 | 1000 mA | Display Status/Display Units: 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 | 0 mA | Display Status/Display Units: 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. | Engine idling.= 683 RPM | Display Status/Display Units: X 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. |
| Ignition - On / Vehicle - In Service Mode= 0 RPM | ||
| Engine Torque | Engine idling.= 1 Nm (1 lb ft) | Display Status/Display Units: Nm (. 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. |
| Ignition - On / Vehicle - In Service Mode= -10 Nm (-7 lb ft) | ||
| Gear Ratio | 0.0:1 | Display Status/Display Units: Varies 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 | Engine idling.=9 to 19 V | Display Status/Display Units: X V This parameter displays the system voltage measured by the transmission control module (TCM) at the TCM ignition voltage input circuit. |
| Ignition - On / Vehicle - In Service Mode=B+ | ||
| Line Pressure | Varies 7 kPa (1 PSI) | Display Status/ This parameter displays the actual pressure at the secondary pulley. This is the same as line pressure. |
| Line Pressure Solenoid Valve Current Command | Engine idling.= 906 mA | Display Status/Display Units: 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. |
| Ignition - On / Vehicle - In Service Mode=1000 mA | ||
| Line Pressure Control Solenoid Valve Current | Varies | Display Status/Display Units: mA This parameter displays the current the transmission control module (TCM) is commanding be sent to the Pressure Control Solenoid Valve 1. 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. |
| Line Pressure Control Solenoid Valve Pressure Command | - | Display Status/Display Units: X kPa (X PSI) This parameter displays the pressure the transmission control module (TCM) is commanding the Line Pressure Control Solenoid Valve to supply. |
| Line Pressure Control Solenoid Valve Pressure Command | - | Display Status/Display Units: Yes/No |
| Pressure Control Solenoid Valve 1 | Off | Display Status/Display Units: 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 1 Control Circuit High Voltage Test Status | OK | Display Status/Display Units: OK/Malfunction/Not Run This parameter displays whether a Short to Voltage exists in the Pressure Control Solenoid Valve 1 Control Circuit. |
| Pressure Control Solenoid Valve 1 Control Circuit Low Voltage Test Status | OK | Display Status/Display Units: OK/Malfunction/Not Run This parameter displays whether a short to ground exists in the pressure control solenoid valve 1 control circuit. |
| Pressure Control Solenoid Valve 1 Control Circuit Open Test Status | OK | Display Status/Display Units: OK/Malfunction/Not Run This parameter displays whether an open exists in the pressure control solenoid valve 1 control circuit. |
| Pressure Control Solenoid Valve 2 | Off | Display Status/Display Units: On/Off 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. |
| Pressure Control Solenoid Valve 2 | Off | Display Status/Display Units: 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 | Display Status/Display Units: OK/Malfunction/Not Run This parameter displays whether a short to voltage exists in the pressure control solenoid valve 2 control circuit. |
| Pressure Control Solenoid Valve 2 Control Circuit Low Voltage Test Status | OK | Display Status/Display Units: OK/Malfunction/Not Run This parameter displays whether a short to ground exists in the pressure control solenoid valve 2 control circuit. |
| Pressure Control Solenoid Valve 2 Control Circuit Open Test Status | OK | Display Status/Display Units: OK/Malfunction/Not Run This parameter displays whether an open exists in the pressure control solenoid valve 2 control circuit. |
| Pressure Control Solenoid Valve 2 Current Command | Varies | Display Status/Display Units: mA This parameter displays the current the transmission control module (TCM) is commanding be sent to the Pressure Control Solenoid Valve 2. 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. |
| Pressure Control Solenoid Valve 2 Pressure Command | 0 kPa (0 PSI) | Display Status/Display Units: X kPa (X PSI) This parameter displays the whether the Pressure Control Solenoid Valve 2 is being commanded. |
| Pressure Control Solenoid Valve 2 Pressure Command | No | Display Status/Display Units: Yes/No This parameter displays the whether the Pressure Control Solenoid Valve 2 is being commanded on. |
| Pressure Control Solenoid Valve 3 | Off | Display Status/Display Units: 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 | Display Status/Display Units: OK/Malfunction/Not Run This parameter displays whether a short to voltage exists in the pressure control solenoid valve 3 control circuit. |
| Pressure Control Solenoid Valve 3 Control Circuit Low Voltage Test Status | OK | Display Status/Display Units: OK/Malfunction/Not Run This parameter displays whether a short to ground exists in the pressure control solenoid valve 3 control circuit. |
| Pressure Control Solenoid Valve 3 Control Circuit Open Test Status | OK | Display Status/Display Units: OK/Malfunction/Not Run This parameter displays whether an open exists in the pressure control solenoid valve 3 control circuit. |
| Pressure Control Solenoid Valve 3 Current Command | Varies | Display Status/Display Units: mA This parameter displays the current the transmission control module (TCM) is commanding be sent to the Pressure Control Solenoid Valve 3. 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. |
| Pressure Control Solenoid Valve 3 Pressure Command | 0 kPa (0 PSI) | Display Status/Display Units: X kPa (X PSI) |
| Pressure Control Solenoid Valve 3 Pressure Command | - | Display Status/Display Units: Yes/No This parameter displays the whether the Pressure Control Solenoid Valve 3 is being commanded. |
| Pressure Control Solenoid Valve 4 | Off | Display Status/Display Units: 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 | Display Status/Display Units: OK/Malfunction/Not Run This parameter displays whether a short to voltage exists in the pressure control solenoid valve 4 control circuit. |
| Pressure Control Solenoid Valve 4 Control Circuit Low Voltage Test Status | OK | Display Status/Display Units: OK/Malfunction/Not Run This parameter displays whether a short to ground exists in the pressure control solenoid valve 4 control circuit. |
| Pressure Control Solenoid Valve 4 Control Circuit Open Test Status | OK | Display Status/Display Units: OK/Malfunction/Not Run This parameter displays whether an open exists in the pressure control solenoid valve 4 control circuit. |
| Pressure Control Solenoid Valve 4 Current Command | Varies | Display Status/Display Units: mA This parameter displays the current the transmission control module (TCM) is commanding be sent to the Pressure Control Solenoid Valve 4. 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. |
| Pressure Control Solenoid Valve 4 Pressure Command | - | Display Status/Display Units: Yes/No This parameter displays the whether the Pressure Control Solenoid Valve 4 is being commanded. |
| Primary Pulley Speed | Engine idling.= 663 RPM | Display Status/Display Units: X 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. |
| Ignition - On / Vehicle - In Service Mode= 35 RPM | ||
| Pulley Gear-Ratio Command | 4.29:1 | Display Status/Display Units: Varies |
| Secondary Pulley Speed | Engine idling.= 304 RPM | Display Status/Display Units: X 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. |
| Ignition - On / Vehicle - In Service Mode= 36 RPM | ||
| TCC Pressure Control Solenoid Valve Current Command | Varies | Display Status/Display Units: mA This parameter displays the current 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. |
| TCC Solenoid Valve Pressure Command | Varies | Display Status/Display Units: X kPa (X PSI) This parameter displays the commanded pressure at the TCC Pressure Control Solenoid Valve. |
| TCC Slip Speed | Engine idling.= 38 RPM | Display Status/Display Units: X 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. |
| Ignition - On / Vehicle - In Service Mode= -34 RPM | ||
| Transmission Gear | - | Display Status/Display Units: Neutral/1st Gear/2nd Gear |
| Transmission Fluid Pressure Switch 1 | High | Display Status/Display Units: 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 | Ignition - On / Vehicle - In Service Mode= -34 RPM | Display Status/Display Units: 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 Line Pressure Sensor. |
| Transmission Fluid Temperature | Varies | Display Status/Display Units: X°C (X°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 | Engine idling.=641 RPM | Display Status/Display Units: X 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). |
| Ignition - On / Vehicle - In Service Mode= 0 RPM | ||
| Transmission OSS | Engine idling.= 0 RPM | Display Status/Display Units: X RPM This parameter displays the rotational speed of the transmission output shaft/final gear expressed as revolutions per minute. |
| Ignition - On / Vehicle - In Service Mode= 0 RPM | ||
| Transmission Range Switch | Park | Display Status/Display Units: Park/Reverse/Neutral/Drive/Low/Invalid This parameter displays the current position of the transmission range switch. |
| Transmission Service Fast Learn Enable | - | Display Status/Display Units: On/Off |
| Transmission Service Fast Learn Status | Fast Learn Complete | Display Status/Display Units: Fast Learn Disabled Fast Learn Complete Service Brake Must be Applied Sump Temp Below Operating Range Sump Temp Above Operating Range Park/Neutral Must Be Selected Drive Must Be Selected Reverse Must Be Selected Max Throttle/Eng Speed Exceeded Low Engine Speed Detected Max Output Speed Exceeded Trans Purge in Progress Drive Calibration test in Progress Drive Calibration test Complete Reverse Calibration test in Progress Abort-Test Criteria Not Met Abort-Test Failed |
| Vehicle Speed Sensor | 0 km/h (0 MPH) | Display Status/Display Units: X km/h (X 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 |
|---|---|
| Auxiliary Transmission Fluid Pump | This Output Control overrides the Auxiliary Transmission Fluid Pump Command Functional requirements:
|
| Auxiliary Transmission Fluid Pump Device Control | This Output Control commands the Auxiliary Transmission Fluid Pump ON or OFF Functional requirements:
|
| Auxiliary Transmission Fluid Pump Relay | This Output Control overrides the Auxiliary Transmission Fluid Pump Relay Command Functional requirements:
|
| Auxiliary Transmission Fluid Pump Relay Device Control | This Output Control overrides the commands the Auxiliary Transmission Fluid Pump Relay ON or OFF Functional requirements:
|
| Pressure Control Solenoid Valve 1 | This Output Control is also known as the Transmission Line Pressure Solenoid Current Device Control or the Line Pressure Solenoid Valve Current Command This Output Control overrides the Actual Pressure Control Solenoid Valve 1 Current which is also known as the Actual Line Pressure Control Solenoid Valve Current 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 2 | This Output Control is also known as the Primary Pulley Pressure Solenoid Current Device Control This Output Control overrides the Pressure Control Solenoid Valve 2 Current Command 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 3 | This Output Control is also known as the Low Brake Clutch Pressure Solenoid Current Device Control This Output Control overrides the Pressure Control Solenoid Valve 3 Current Command 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 4 | This Output Control is also known as the High Clutch Reverse Brake Pressure Solenoid Current Device Control This Output Control overrides the Pressure Control Solenoid Valve 4 Current Command 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. |
| Service Fast Learn Enable | This Output Control overrides the TCC Pressure Control Solenoid Valve Current Command Functional requirements:
|
| TCC Pressure Control Solenoid Valve | This Output Control is also known as the Torque Converter Clutch Pressure Solenoid Current Device Control This Output Control overrides the TCC Pressure Control Solenoid Valve Current Command 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. |