This list explains each data message displayed on the scan tool. This information will assist you in tracking down emissions or driveability DTCs, because you can view the displays while you are driving the vehicle. Refer to Diagnostic System Check - Automatic Transmission for additional information.

1-2 Shift Error: This display is the difference between the desired shift time and the actual shift time for the specific shift indicated on the scan tool. The desired shift time is calculated by the TCM. The actual shift time is obtained by measuring the time required for the input shaft to decelerate from the previous ratio to the current ratio. If the number is negative, the actual shift took longer than desired. If the number is positive, the shift occurred more quickly than desired.

1-2 Shift Time: This display is the actual time of the last shift. The actual shift time is obtained by measuring the time required for the input shaft to decelerate from the previous ratio to the current ratio.

1-2 Sol.: The 1-2 Solenoid (Sol.) parameter indicates the current commanded state of the shift solenoids. All three of the 5L40-E shift solenoids are normally-closed, which means that no fluid passes through when the solenoid is commanded OFF. When the TCM commands the solenoid ON, the solenoid opens and allows fluid to flow through. Refer to Shift Solenoid Valve State and Gear Ratio .

1-2 Sol. CKT Status:  The 1-2 Solenoid (Sol.) Circuit (CKT) Status parameter interprets the solenoid driver feedback voltage signal and displays the circuit status on the scan tool. If the voltage is low when the solenoid is commanded OFF, the scan tool will display Open/Short to GND. If the voltage is high when the solenoid is commanded ON, the scan tool will display Short to Volts.

1-2 TAP Cell: The 1-2 Transmission Adaptive Pressure (TAP) Cell parameter displays the amount of adaptive pressure, based on 17 N·m (12.5 lb ft) of engine torque increment per cell, added or subtracted from shift pressure during an upshift. A positive number indicates that the TCM has detected long shifts and has increased the PC solenoid duty cycle in order to decrease shift time. A negative number indicates that the TCM has detected short shifts decreased the PC solenoid duty cycle in order to increase shift time.

2-3 Shift Error: This display is the difference between the desired shift time and the actual shift time for the specific shift indicated on the scan tool. The desired shift time is calculated by the TCM. The actual shift time is obtained by measuring the time required for the input shaft to decelerate from the previous ratio to the current ratio. If the number is negative, the actual shift took longer than desired. If the number is positive, the shift occurred more quickly than desired.

2-3 Shift Time: This display is the actual time of the last shift. The actual shift time is obtained by measuring the time required for the input shaft to decelerate from the previous ratio to the current ratio.

2-3 Sol.: The 2-3 Solenoid (Sol.) parameter indicates the current commanded state of the shift solenoids. All three of the 5L40-E shift solenoids are normally-closed, which means that no fluid passes through when the solenoid is commanded OFF. When the TCM commands the solenoid ON, the solenoid opens and allows fluid to flow through. Refer to Shift Solenoid Valve State and Gear Ratio .

2-3 Sol. CKT Status:  The 2-3 Solenoid (Sol.) Circuit (CKT) Status parameter interprets the solenoid driver feedback voltage signal and displays the circuit status on the scan tool. If the voltage is low when the solenoid is commanded OFF, the scan tool will display Open/Short to GND. If the voltage is high when the solenoid is commanded ON, the scan tool will display Short to Volts.

2-3 TAP Cell: The 2-3 Transmission Adaptive Pressure (TAP) Cell parameter displays the amount of adaptive pressure, based on 17 N·m (12.5 lb ft) of engine torque increment per cell, added or subtracted from shift pressure during an upshift. A positive number indicates that the TCM has detected long shifts and has increased the PC solenoid duty cycle in order to decrease shift time. A negative number indicates that the TCM has detected short shifts decreased the PC solenoid duty cycle in order to increase shift time.

3-4 Shift Error: This display is the difference between the desired shift time and the actual shift time for the specific shift indicated on the scan tool. The desired shift time is calculated by the TCM. The actual shift time is obtained by measuring the time required for the input shaft to decelerate from the previous ratio to the current ratio. If the number is negative, the actual shift took longer than desired. If the number is positive, the shift occurred more quickly than desired.

3-4 Shift Time: This display is the actual time of the last shift. The actual shift time is obtained by measuring the time required for the input shaft to decelerate from the previous ratio to the current ratio.

3-4 TAP Cell: The 3-4 Transmission Adaptive Pressure (TAP) Cell parameter displays the amount of adaptive pressure, based on 17 N·m (12.5 lb ft) of engine torque increment per cell, added or subtracted from shift pressure during an upshift. A positive number indicates that the TCM has detected long shifts and has increased the PC solenoid duty cycle in order to decrease shift time. A negative number indicates that the TCM has detected short shifts decreased the PC solenoid duty cycle in order to increase shift time.

4-5 Shift Error: This display is the difference between the desired shift time and the actual shift time for the specific shift indicated on the scan tool. The desired shift time is calculated by the TCM. The actual shift time is obtained by measuring the time required for the input shaft to decelerate from the previous ratio to the current ratio. If the number is negative, the actual shift took longer than desired. If the number is positive, the shift occurred more quickly than desired.

4-5 Shift Time: This display is the actual time of the last shift. The actual shift time is obtained by measuring the time required for the input shaft to decelerate from the previous ratio to the current ratio.

4-5 Sol.: The 4-5 Solenoid (Sol.) parameter indicates the current commanded state of the shift solenoids. All three of the 5L40-E shift solenoids are normally-closed, which means that no fluid passes through when the solenoid is commanded OFF. When the TCM commands the solenoid ON, the solenoid opens and allows fluid to flow through. Refer to Shift Solenoid Valve State and Gear Ratio .

4-5 Sol. CKT Status:  The 4-5 Solenoid (Sol.) Circuit (CKT) Status parameter interprets the solenoid driver feedback voltage signal and displays the circuit status on the scan tool. If the voltage is low when the solenoid is commanded OFF, the scan tool will display Open/Short to GND. If the voltage is high when the solenoid is commanded ON, the scan tool will display Short to Volts.

4-5 TAP Cell (4-16): The 4-5 Transmission Adaptive Pressure (TAP) Cell parameter displays the amount of adaptive pressure, based on 17 N·m (12.5 lb ft) of engine torque increment per cell, added or subtracted from shift pressure during an upshift. A positive number indicates that the TCM has detected long shifts and has increased the PC solenoid duty cycle in order to decrease shift time. A negative number indicates that the TCM has detected short shifts decreased the PC solenoid duty cycle in order to increase shift time.

A/C Clutch: The Air Conditioner (A/C) represents the commanded state of the A/C clutch control relay. The clutch should be engaged whenever ON is displayed. The ECM will compensate for the additional engine load that is accompanied with the A/C clutch engaged.

APP Angle: The Accelerator Pedal Position parameter indicates the position of the accelerator pedal. 0 % indicates that the accelerator pedal is fully released. 100 % indicates that the accelerator is fully depressed. The value indicated may not correspond to the TP angle value.

Commanded Gear: This display indicates the commanded gear of the TCM.

Cruise: When the display indicates ENABLED, the ECM is allowing cruise control operation. When the display indicates DISABLED, the ECM has disabled cruise control operation. The TCM modifies upshift and downshift patterns when cruise control is enabled.

ECT: The Engine Coolant Temperature (ECT) parameter displays the engine coolant temperature data that the TCM receives from the ECM on the CAN bus. The TCM uses the ECT information to modify shift patterns in cold weather and as a rationality check for the transmission fluid temperature sensor.

Engine Speed: This parameter indicates the rotational speed of the engine expressed in revolutions per minute. Engine speed is computed by the ECM from the crankshaft position sensor input.

Engine Torque: This display indicates the amount of torque that is delivered from the engine.

Gear Ratio: This display is the actual transmission gear ratio as the transmission operates through all drive ranges including REVERSE and PARK/NEUTRAL. The gear ratio parameter is obtained by dividing the input shaft speed by the output shaft speed.

Ignition Voltage: This represents the system voltage measured by the TCM at its ignition input.

IMS A/B/C/P: The Internal Mode Switch (IMS) parameter displays the four inputs from the automatic transmission. HI indicates an ignition voltage signal and LOW indicates a 0 voltage signal.

IMS Range: The Internal Mode Switch (IMS) displays the decoded status of the four A/B/C/P inputs from the automatic transmission. If a valid combination of inputs is not received by the TCM, Invalid will be displayed.

Last Shift Time: This display indicates the actual shift time of the most recent upshift.

PC Sol. Actual Current: The Pressure Control (PC) Solenoid (Sol.) Actual Current parameter displays the actual current flow through the pressure control solenoid circuit which is monitored by the TCM. High current results in low line pressure. Low current results in high line pressure.

PC Solenoid Duty Cycle: The Pressure Control (PC) Solenoid Duty Cycle parameter displays the commanded state of the pressure control solenoid expressed as a percent of ON time. No current flow indicates zero ON time or 0% duty cycle. High current flow is approximately 60% duty cycle at idle.

PC Sol. Ref. Current: The Pressure Control (PC) Solenoid (Sol.) Reference (Ref.) Current displays the amount of current which the TCM has commanded through the pressure control solenoid circuit. High current results in low line pressure. Low current results in high line pressure.

SS TAP Cell (0-10): The Steady State (SS) Transmission Adaptive Pressure (TAP) Cell parameter displays the pressure modification required during a steady-state cruise in a single gear, with or without TCC application. Line pressure is either increased in order to prevent component slippage or decreased in order to minimize pumping losses.

Steady State TAP 1 GR: The Steady State Transmission Adapt Pressure (TAP) 1st Gear (1 GR) parameter displays the amount of pressure used to help prevent transmission component slip. By analyzing the transmission gear ratio when commanding first gear, the TCM will command additional line pressure in order to maintain correct first gear ratio. The amount of additional pressure is determined by the TCM and is used to increase the base line pressure. The larger the value, the greater the increase to line pressure.

Steady State TAP 1 GR/TCC: The Steady State Transmission Adapt Pressure (TAP) 1st Gear (1 GR) with Torque Converter Clutch (TCC) apply parameter displays the amount of pressure used to help prevent transmission component slip. By analyzing the transmission gear ratio when commanding first gear and the TCC on, the TCM will command additional line pressure in order to maintain correct first gear ratio with the TCC applied. The amount of additional pressure is determined by the TCM and is used to increase the base line pressure. The larger the value, the greater the increase to line pressure.

Steady State TAP 2 GR: The Steady State Transmission Adapt Pressure (TAP) 2nd Gear (2 GR) parameter displays the amount of pressure used to help prevent transmission component slip. By analyzing the transmission gear ratio when commanding second gear, the TCM will command additional line pressure in order to maintain correct second gear ratio. The amount of additional pressure is determined by the TCM and is used to increase the base line pressure. The larger the value, the greater the increase to line pressure.

Steady State TAP 2 GR/TCC: The Steady State Transmission Adapt Pressure (TAP) 2nd Gear (2 GR) with Torque Converter Clutch (TCC) apply parameter displays the amount of pressure used to help prevent transmission component slip. By analyzing the transmission gear ratio when commanding second gear and the TCC on, the TCM will command additional line pressure in order to maintain correct second gear ratio with the TCC applied. The amount of additional pressure is determined by the TCM and is used to increase the base line pressure. The larger the value, the greater the increase to line pressure.

Steady State TAP 3 GR: The Steady State Transmission Adapt Pressure (TAP) 3rd Gear (3 GR) parameter displays the amount of pressure used to help prevent transmission component slip. By analyzing the transmission gear ratio when commanding third gear, the TCM will command additional line pressure in order to maintain correct third gear ratio. The amount of additional pressure is determined by the TCM and is used to increase the base line pressure. The larger the value, the greater the increase to line pressure.

Steady State TAP 3 GR/TCC: The Steady State Transmission Adapt Pressure (TAP) 3rd Gear (3 GR) with Torque Converter Clutch (TCC) apply parameter displays the amount of pressure used to help prevent transmission component slip. By analyzing the transmission gear ratio when commanding third gear and the TCC on, the TCM will command additional line pressure in order to maintain correct third gear ratio with the TCC applied. The amount of additional pressure is determined by the TCM and is used to increase the base line pressure. The larger the value, the greater the increase to line pressure.

Steady State TAP 4 GR: The Steady State Transmission Adapt Pressure (TAP) 4th Gear (4 GR) parameter displays the amount of pressure used to help prevent transmission component slip. By analyzing the transmission gear ratio when commanding fourth gear, the TCM will command additional line pressure in order to maintain correct fourth gear ratio. The amount of additional pressure is determined by the TCM and is used to increase the base line pressure. The larger the value, the greater the increase to line pressure.

Steady State TAP 4 GR/TCC: The Steady State Transmission Adapt Pressure (TAP) 4th Gear (4 GR) with Torque Converter Clutch (TCC) apply parameter displays the amount of pressure used to help prevent transmission component slip. By analyzing the transmission gear ratio when commanding fourth gear and the TCC on, the TCM will command additional line pressure in order to maintain correct fourth gear ratio with the TCC applied. The amount of additional pressure is determined by the TCM and is used to increase the base line pressure. The larger the value, the greater the increase to line pressure.

Steady State TAP 5 GR: The Steady State Transmission Adapt Pressure (TAP) 5th Gear (5 GR) parameter displays the amount of pressure used to help prevent transmission component slip. By analyzing the transmission gear ratio when commanding fifth gear, the TCM will command additional line pressure in order to maintain correct fifth gear ratio. The amount of additional pressure is determined by the TCM and is used to increase the base line pressure. The larger the value, the greater the increase to line pressure.

Steady State TAP 5 GR/TCC: The Steady State Transmission Adapt Pressure (TAP) 5th Gear (5 GR) with Torque Converter Clutch (TCC) apply parameter displays the amount of pressure used to help prevent transmission component slip. By analyzing the transmission gear ratio when commanding fifth gear and the TCC on, the TCM will command additional line pressure in order to maintain correct fifth gear ratio with the TCC applied. The amount of additional pressure is determined by the TCM and is used to increase the base line pressure. The larger the value, the greater the increase to line pressure.

Steady State TAP Reverse: The Steady State Transmission Adapt Pressure (TAP) Reverse gear parameter displays the amount of pressure used to help prevent transmission component slip. By analyzing the transmission gear ratio when commanding reverse gear, the TCM will command additional line pressure in order to maintain correct reverse gear ratio. The amount of additional pressure is determined by the TCM and is used to increase the base line pressure. The larger the value, the greater the increase to line pressure.

TCC Brake Switch: The Torque Convertor Clutch (TCC) Brake Switch parameter displays the status of the TCC brake switch circuit input to the TCM. When the brake pedal is released, the scan tool should indicate OPEN. When the brake pedal is applied, the scan tool should indicate CLOSED.

TCC Duty Cycle: The Torque Convertor Clutch (TCC) Duty Cycle parameter displays the commanded state of the TCC PWM solenoid expressed as a percent of ON time. 90% represents a fully energized commanded state and 0% represents a de-energized commanded state.

TCC Duty Cycle Sol. CKT Status:  The Torque Convertor Clutch (TCC) Duty Cycle Solenoid (Sol.) Circuit (CKT) Status parameter interprets the solenoid driver feedback voltage signal and displays the circuit status on the scan tool. If the voltage is low when the solenoid is commanded OFF, the scan tool will display Open/Short to GND. If the voltage is high when the solenoid is commanded ON, the scan tool will display Short to Volts.

TCC Slip Speed: The Torque Convertor Clutch (TCC) Slip Speed parameter displays the difference between the engine RPM and the RPM of the input shaft of the transmission. A negative value indicates that the engine RPM is less than the RPM of the input shaft, deceleration. A positive value indicates that the engine RPM is greater than the RPM of the input shaft.

Traction Control: This parameter indicates if the ECM is reducing torque to a level below that which the driver has commanded due to drive wheel slippage.

Trans. Fluid. Temp.: The Transmission (Trans.) Fluid Temperature (Temp.) parameter displays the temperature conversion of the voltage input signal to the TCM from the transmission fluid temperature (TFT) sensor. The TFT sensor is a negative temperature coefficient thermistor. The resistance decreases as the temperature increases. As the transmission fluid temperature increases, the decreasing resistance causes the 5 volt reference voltage to be pulled progressively lower.

Trans. Oil Life: The Transmission (Trans.) Oil Life parameter represents the remaining Transmission Oil Life that is calculated and maintained by the TCM. This parameter is displayed when the Trans. Oil Life Reset is initiated with the scan tool.

Transmission Hot Mode: This display indicates transmission hot mode operation due to high transmission fluid temperature. OFF indicates that the transmission fluid temperature has not exceeded 130°C (266°F). ON indicates that the transmission fluid temperature has exceeded 130°C (266°F) and has not cooled to 120°C (248°F) for more than five seconds.

Transmission ISS: The Transmission Input Speed Sensor (ISS) parameter displays the rotational speed of the transmission input shaft expressed in revolutions per minute.

Transmission OSS: The Transmission Output Shaft Sensor (OSS) parameter displays the rotational speed of the transmission output shaft expressed in revolutions per minute.

Vehicle Speed: The vehicle speed sensor signal is converted by the TCM to be displayed in mph and km/h.