GM Service Manual Online
For 1990-2009 cars only
APP Angle: This parameter displays the position of the accelerator pedal. A display of 0 percent indicates that the accelerator pedal is fully released. A display of 100 percent indicates that the accelerator is fully depressed. The value indicated may not correspond to the TP angle value.

Brake Switch: This parameter displays the state of the brake switch circuit input. The scan tool will display Applied when the brake pedal is depressed and Released when the brake pedal is released.

Commanded Gear: This parameter displays the current commanded state of the shift solenoid valves. The scan tool displays 1, 2, 3, 4 or 5.

Cruise: This parameter displays the commanded state of the cruise control system. The scan tool displays ENABLED or DISABLED. When the display indicates ENABLED, the PCM is allowing cruise control operation. When the display indicates DISABLED, the PCM has disabled cruise control operation. When the cruise control display is ENABLED, shift patterns will be altered for 2-3 and 3-4 upshifts or 4-3 and 3-2 downshifts.

ECT: This parameter displays the input signal from the engine coolant temperature (ECT) sensor. ECT is high at 151°C (304°F) when the signal voltage is low, 0 volt. ECT is low at -40°C (-40°F) when the signal voltage is high, 5 volt.

Engine Run Time: This parameter displays a measure in Hr:Min:Sec of the length of time the engine has been operating. When the ignition is cycled to OFF, the value is reset to zero.

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

Engine Torque: This parameter displays a calculated value based on engine load, throttle position, mass air flow, and other engine inputs. This parameter is accurate to within 20 N·m (15 ft lb) of actual measured engine torque.

Gear Ratio: This parameter displays the actual transmission gear ratio. The scan tool displays the gear ratio calculated from the automatic transmission input shaft speed sensor (AT ISS) and the automatic transmission output shaft speed sensor (AT OSS) inputs.

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

Last 1-2 Shift Status: This parameter displays the shift quality of the last 1-2 gearshift. The scan tool displays Good, Long, Short, Tie-Up, Flare, or Inconclusive. Inconclusive is displayed if the conditions for determining the last shift status were not met.

Last 2-1 Shift Status: This parameter displays the shift quality of the last 2-1 gearshift. The scan tool displays Good, Long, Short, Tie-Up, Flare, or Inconclusive. Inconclusive is displayed if the conditions for determining the last shift status were not met.

Last 2-3 Shift Status: This parameter displays the shift quality of the last 2-3 gearshift. The scan tool displays Good, Long, Short, Tie-Up, Flare, or Inconclusive. Inconclusive is displayed if the conditions for determining the last shift status were not met.

Last 2-4 Shift Status: This parameter displays the shift quality of the last 2-4 gearshift. The scan tool displays Good, Long, Short, Tie-Up, Flare, or Inconclusive. Inconclusive is displayed if the conditions for determining the last shift status were not met.

Last 3-2 Shift Status: This parameter displays the shift quality of the last 3-2 gearshift. The scan tool displays Good, Long, Short, Tie-Up, Flare, or Inconclusive. Inconclusive is displayed if the conditions for determining the last shift status were not met.

Last 3-4 Shift Status: This parameter displays the shift quality of the last 3-4 gearshift. The scan tool displays Good, Long, Short, Tie-Up, Flare, or Inconclusive. Inconclusive is displayed if the conditions for determining the last shift status were not met.

Last 4-2 Shift Status: This parameter displays the shift quality of the last 4-2 gearshift. The scan tool displays Good, Long, Short, Tie-Up, Flare, or Inconclusive. Inconclusive is displayed if the conditions for determining the last shift status were not met.

Last 4-3 Shift Status: This parameter displays the shift quality of the last 4-3 gearshift. The scan tool displays Good, Long, Short, Tie-Up, Flare, or Inconclusive. Inconclusive is displayed if the conditions for determining the last shift status were not met.

Last 4-5 Shift Status: This parameter displays the shift quality of the last 4-5 gearshift. The scan tool displays Good, Long, Short, Tie-Up, Flare, or Inconclusive. Inconclusive is displayed if the conditions for determining the last shift status were not met.

Last 5-4 Shift Status: This parameter displays the shift quality of the last 5-4 gearshift. The scan tool displays Good, Long, Short, Tie-Up, Flare, or Inconclusive. Inconclusive is displayed if the conditions for determining the last shift status were not met.

Line PC Sol. Actual Current: This parameter displays the actual current flow of the line pressure control (PC) solenoid valve circuit. The scan tool displays current flow in amps. A reading of 0.00 amps, no current is flowing, indicates high line pressure. A reading of 1.10 amps, a high flow of current, indicates low line pressure.

Line PC Sol. CKT Status: This parameter displays whether an open, short to voltage or ground exists in the line pressure control (PC) solenoid valve feedback signal circuit. The scan tool displays OK, Open/Short to Volts, Short to GND, or Indeterminate.

Line PC Sol. Duty Cycle: This parameter displays the commanded state of the line pressure control (PC) solenoid valve. The scan tool displays the percentage of the PC solenoid valve energized On time. A reading of 0 percent indicates zero On time, or a non-energized, commanded Off, state. A reading of 100 percent represents a fully energized, commanded On, state.

Line PC Sol. Ref. Current: This parameter displays the commanded reference current flow of the line pressure control (PC) solenoid valve circuit. The scan tool displays current flow in amps. A reading of 0.00 amps, no current is flowing, indicates high line pressure. A reading of 1.10 amps, a high flow of current, indicates low line pressure.

Shift PC Sol. Actual Current: This parameter displays the actual current flow of the shift pressure control (PC) solenoid valve circuit. The scan tool displays current flow in amps. A reading of 0.00 amps, no current is flowing, indicates an actual high shift pressure. A reading of 1.10 amps, a high flow of current, indicates low shift pressure.

Shift PC Sol. CKT Status: This parameter displays whether an open, short to voltage or ground exists in the shift pressure control (PC) solenoid valve feedback signal circuit. The scan tool displays OK, Open/Short to Volts, Short to GND.

Shift PC Sol. Duty Cycle: This parameter displays the commanded state of the shift pressure control (PC) solenoid valve. The scan tool displays the percentage of the shift PC solenoid valve energized ON time. A reading of 0 percent indicates zero ON time, a non-energized commanded OFF state. A reading of 100 percent represents an energized commanded ON state.

Shift PC Sol. Ref. Current: This parameter displays the commanded reference current flow of the shift pressure control (PC) solenoid valve circuit. The scan tool displays current flow in amps. A reading of 0.00 amps, no current is flowing, indicates an actual high shift pressure. A reading of 1.10 amps, a high flow of current, indicates low shift pressure.

Shift Sol. 1 CKT Status: This parameter displays whether an open, short to voltage or ground exists in the shift solenoid valve 1 feedback signal circuit. The scan tool displays OK, Open/Short to Volts, Short to GND.

Shift Solenoid 1: This parameter displays the commanded state of the reverse, 1st shift solenoid valve (S1). The scan tool displays On/Off.

Shift Sol. 2 CKT Status: This parameter displays whether an open or short to voltage or ground exists in the 2-3, 3-4 shift solenoid valve (S2) feedback signal circuit. The scan tool displays OK, Open/Short to Volts, or Short to GND.

Shift Solenoid 2: This parameter displays the commanded state of the 2-3, 3-4 shift solenoid valve (S2). The scan tool displays On/Off.

Shift Sol. 3 CKT Status: This parameter displays whether an open or short to voltage or ground exists in the 1-2, 2-3, reverse, shift solenoid valve (S3) feedback signal. The scan tool displays OK, Open/Short to Volts, or Short to GND.

Shift Solenoid 3: This parameter displays the commanded state of the 1-2, 2-3, reverse shift solenoid valve (S3). The scan tool displays On/Off.

Shift Sol. 4 CKT Status: This parameter displays whether an open or short to voltage or ground exists in the 3-4, 4-5 shift solenoid valve (S4) feedback signal circuit. The scan tool displays OK, Open/Short to Volts, or Short to GND.

Shift Solenoid 4: This parameter displays the commanded state of the 3-4, 4-5 shift solenoid valve (S4). The scan tool displays On/Off.

Shift Sol. 5 CKT Status: This parameter displays whether an open or short to voltage or ground exists in the reverse shift solenoid valve (S5) feedback signal circuit. The scan tool displays OK, Open/Short to Volts, or Short to GND.

Shift Solenoid 5: This parameter displays the commanded state of the reverse shift solenoid valve (S5). The scan tool displays On/Off.

TCC PC Sol. Actual Current: This parameter displays the actual current of the torque converter clutch (TCC) lock up pressure control (PC) solenoid valve circuit. The scan tool displays current flow in amps. A reading of 0.00 amps, no current flowing, indicates a low TCC apply pressure. A reading of 1.10 amps, a high flow of current, indicates a high TCC apply pressure.

TCC PC Sol. CKT Status: This parameter displays whether an open or short to voltage or ground exists in the torque converter clutch (TCC) pressure control (PC) solenoid valve feedback signal circuit. The scan tool displays OK, Open/Short to Volts, Short to GND, or Indeterminate.

TCC PC Sol. Duty Cycle: This parameter displays the commanded On time of the torque converter clutch (TCC) solenoid valve. The scan tool displays On time in percentage. A reading of 100 percent represents an energized, commanded On state. A reading of 0 percent represents a non-energized commanded OFF state.

TCC PC Sol. Ref. Current: This parameter displays the commanded reference current flow of the torque converter clutch (TCC) lock up pressure control (PC) solenoid valve circuit. The scan tool displays current flow in amps. A reading of 0.00 amps, no current flow, indicates an actual high commanded apply pressure. A reading of 1.10 amps, a high flow of current, indicates a high commanded TCC apply pressure.

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

TR Sw.: This parameter displays the decoded status of the four A/B/C/P inputs from the transmission range switch. The scan tool displays Park, Reverse, Neutral, Drive, Intermediate, Low, and invalid. If a valid combination of inputs is not detected, invalid will be displayed.

TR Sw. A/B/C/P: This parameter displays the status of the four inputs from the transmission range switch. The scan tool displays HI/LOW. HI indicates an ignition voltage input to the control module. LOW indicates a zero voltage input to the control module.

Trans. Fluid Temp.: 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 volt. Transmission fluid temperature is low, -40°C (-40°F), when signal voltage is high, 5 volt.

Trans. Oil Life: This parameter displays the transmission oil life remaining. The scan tool displays remaining oil life in percentage. The transmission oil life calculation is based on transmission fluid temperature and engine run time.

Trans. Protection Mode: This parameter displays the status of the transmission protection mode. The scan tool displays Yes/No. Yes indicates that a fault has occurred, and that the transmission protection mode is active and has inhibited certain gears, as well as taken other actions to prevent damage.

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 (266°F). On indicates that the TFT has exceeded 130°C (266°F) and has not cooled to 120°C (248°F) for greater that 5 seconds. These numbers are approximate and differ with transmissions.

Transmission ISS: This parameter displays the rotational speed of the transmission input shaft. The scan tool displays input shaft speed as revolutions per minute (RPM).

Transmission OSS: This parameter displays the rotational speed of the transmission output shaft. The scan tool displays output shaft speed as revolutions per minute (RPM). On four-wheel drive applications, the transfer case output shaft speed is measured.

Vehicle Speed: This parameter displays the speed at which the vehicle is traveling. The scan tool displays vehicle speed as kilometers per hour (km/h), miles per hour (MPH). The vehicle speed is calculated based on the input signal from the automatic transmission output shaft speed sensor.