GM Service Manual Online
For 1990-2009 cars only

Scan Tool Data Definitions V6

1-2 Shift Error: This parameter displays the difference between the desired 1-2 shift time and actual 1-2 shift time. A positive number indicates a firm or fast shift and the actual shift time was shorter than the desired shift time. A negative number indicates a soft shift and the actual shift time was longer than the desired shift time. This value is only accurate if the shift was adaptable.

1-2 Shift Time: This parameter displays the actual time of the last 1-2 shift. The shift time is based on the engine RPM. drop after the commanded 1-2 shift. This value is only accurate if the shift was adaptable.

1-2 TAP Cell: This parameter displays the amount of transmission adaptive pressure (TAP), based on 17 N·m of engine torque increment per cell, added to or subtracted from shift pressure during a 1-2 upshift. A positive number indicates that long shifts have been detected and PC solenoid pressure has been added in order to decrease shift time. A negative number indicates that short shifts have been detected and PC solenoid pressure has been subtracted in order to increase shift time.

2-3 Shift Error: This parameter displays the difference between the desired 2-3 shift time and the actual 2-3 shift time. A positive number indicates a firm or fast shift, the actual shift time was shorter than the desired shift time. A negative number indicates a soft or slow shift, the actual shift time was longer than the desired shift time. This value is only accurate if the shift was adaptable.

2-3 Shift Time: This parameter displays the actual time of the last 2-3 shift. The shift time is based on the engine RPM. drop after the commanded 2-3 shift. This value is only accurate if the shift was adaptable.

2-3 TAP Cell: This parameter displays the amount of transmission adaptive pressure (TAP), based on 17 N·m of engine torque increment per cell, added to or subtracted from shift pressure during a 2-3 upshift. A positive number indicates that long shifts have been detected and PC solenoid pressure has been added in order to decrease shift time. A negative number indicates that short shifts have been detected and PC solenoid pressure has been subtracted in order to increase shift time.

3-4 Shift Error: This parameter displays the difference between the desired 3-4 shift time and the actual 3-4 shift time. A positive number indicates a firm or fast shift, the actual shift time was shorter than the desired shift time. A negative number indicates a soft or slow shift, the actual shift time was longer than the desired shift time. This value is only accurate if the shift was adaptable.

3-4 Shift Time: This parameter displays the actual time of the last 3-4 shift. The shift time is based on the engine RPM. drop after the commanded 3-4 shift. This value is only accurate if the shift was adaptable.

3-4 TAP Cell: This parameter displays the amount of transmission adaptive pressure (TAP), based on 17 N·m of engine torque increment per cell, added to or subtracted from shift pressure during a 3-4 upshift. A positive number indicates that long shifts have been detected and PC solenoid pressure has been added in order to decrease shift time. A negative number indicates that short shifts have been detected and PC solenoid pressure has been subtracted in order to increase shift time.

A/C Clutch: This parameter displays the condition of the air conditioning compressor as either ON or OFF.

At Output Speed: This parameter displays the rotational speed of the transmission output shaft. Tech 2 displays output shaft speed as revolutions per minute (RPM).

Commanded Gear: This parameter displays the current transmission adaptive pressure (TAP) cell in use for transmission line pressure adaptation. The cells are based on 17 N·m of engine torque. The higher the engine torque, the higher the current TAP cell. The last cell used will remain displayed until the next adaptable upshift occurs.

Engine Coolant Temperature: This parameter displays the input signal from the engine coolant temperate (ECT) sensor. ECT is high at 151°C when the signal voltage is low, 0 V. ECT is low at -40°C when the signal voltage is high, 5 V.

Engine Speed: This parameter displays the rotational speed of the engine expressed as revolutions per minute.

Engine Torque: This parameter displays the calculated value based on engine load, throttle position, mass air flow, and other engine inputs. This parameter is accurate to within 20 N·m of actual measured engine torque.

Estimate Gear Ratio: This Parameter displays the estimated turbine speed divided by the transmission output speed. Estimated turbine speed is calculated from engine speed and engine torque.

Ignition Voltage: This parameter displays the system voltage measured at the ignition feed.

Latest Shift: This parameter displays the actual time of the last upshift. This value is only accurate if the shift was adaptable.

PCS Actual Current: This parameter displays the current flow through the pressure control solenoid circuit, which is measured by the control module. High current flow results in low line pressure. Low current flow results in high line pressure.

PCS Duty Cycle: This parameter displays the commanded state of the pressure control solenoid, expressed as a percentage of energised on time. A reading of low percent indicates zero on time, non-energised, or no current flow. A high percent at idle indicates maximum on time, energised or high current flow.

PCS Desired Current: This parameter displays the commanded current of the pressure control solenoid circuit. High current results in low line pressure. Low current results in high line pressure.

Shift Pattern: This parameter displays Normal, Power or Cruise depending on what mode the transmission is in.

Shift Solenoid A: This parameter displays the commanded state of the 1-2 shift solenoid valve. When the transmission is in 1st and 4th gear, the display should indicate ON; current is flowing through the solenoid. When the transmission is in 2nd and 3rd gear, the display should indicate OFF; current is not flowing through the solenoid.

Shift Solenoid A Circuit: This parameter displays whether an open or a short to ground, short to battery or the circuit is okay in the 1-2 shift solenoid valve feedback signal. The 1-2 shift solenoid valve must be commanded off and on.

Shift Solenoid B: This parameter displays the commanded state of the 2-3 shift solenoid valve. When the transmission is in 1st and 4th gear, the display should indicate ON; current is flowing through the solenoid. When the transmission is in 2nd and 3rd gear, the display should indicate OFF; current is not flowing through the solenoid.

Shift Solenoid B: This parameter displays whether an open or a short to ground, short to battery or the circuit is okay in the 2-3 shift solenoid valve feedback signal. The 2-3 shift solenoid valve must be commanded off and on.

Speed Rate: This parameter displays the calculated speed ratio of the transmission.

TCC Duty Cycle Circuit: This parameter displays whether an open or a short to ground, short to battery or the circuit is okay in the TCC PWM solenoid valve feedback signal. The TCC PWM solenoid valve must be commanded off and on.

TCC Solenoid: This parameter displays the commanded state of the TCC solenoid. ON; indicates a commanded non-energised state; current is flowing through the solenoid. OFF; indicates a commanded non-energised state; current is not flowing through the solenoid. This commanded state occurs at various vehicle speeds between applications.

TCC Slip Speed: This parameter displays the difference between transmission output speed and engine speed. A negative valve indicates the engine speed is less than the output speed, deceleration. A positive value indicates the engine speed is greater than the output speed, acceleration. A value of zero indicates the engine speed is equal to the output speed, TCC applied.

TCC PWM Solenoid: This parameter displays the commanded percentage of on time for the TCC PWM solenoid. A high percentage represents an on, energised, commanded state. 0 percent represents an off, non-energised, commanded state.

TFP Gear: This parameter displays Park/Neutral, Reverse, Drive4, Drive3, Drive2, Drive1 or Invalid. This parameter is the decoded status of the three A/B/C inputs from the automatic transmission fluid pressure manual valve position switch. If a valid combination of inputs is not detected, invalid will be displayed.

TFP Swi A/B/C: This parameter displays Open 12 V / Closed 0 V for each switch. This parameter indicates the statues of the three inputs from the automatic transmission fluid pressure manual valve position switch assembly.

Throttle Position: This parameter displays a calculated value, which is determined by the accelerator pedal position and the actual throttle position, used to optimise transmission controls. It represents the driver's intended request for torque or acceleration. The range is 0-100%, 0% represents an idle or coast request and 100% represents a request for wide open throttle (WOT).

Torque Converter Efficiency: This parameter displays a ratio of 0.00:1 to 2:1. The ratio is calculates by multiplying the speed ratio by a value related to the 'K factor' of the torque converter. The 'K factor' is the looseness or tightness of the torque converter for a given torque. The nearer the torque converter is to full coupling, i.e. 1:1, the closer the torque converter efficiency number will be to 1.

TR Switch A/B/C/P: This parameter displays the status of the four inputs from the transmission range switch. Tech 2 displays Open 12 V / Closed 0 V. Open 12 V indicates an ignition voltage input to the control module. Closed 0 V indicates a zero voltage input to the control module.

Transmission Fluid Temperature: This parameter displays the input signal of the transmission fluid temperature sensor. Transmission fluid temperature is high, 151°C, when signal voltage is low, 0 V. Transmission fluid temperature is low, -40°C, when signal voltage is high, 5 V.

Transmission Hot Mode: This parameter displays the automatic transmission fluid temperature (TFT) and displays On or Off. Off indicates that the TFT has not exceeded 130°C. On indicates that the TFT has exceeded 130°C and has not cooled to 120°C for greater than 5 seconds. These numbers are approximate and differ with transmissions.

Vehicle Speed: This parameter displays the speed at which the vehicle is travelling. Tech 2 displays vehicle speed as kilometres per hour (km/h). The vehicle speed is calculates based on the input signal from the automatic transmission output shaft speed sensor.