GM Service Manual Online
For 1990-2009 cars only
1-2/3-4 Solenoid: Displays ON/OFF. This parameter is the commanded status of the 1-2/3-4 shift solenoid. When the TCM commands first or fourth gear, the scan tool should display OFF. When the TCM commands second or third gear, the TCM should display ON.

2-3 Solenoid: Displays ON/OFF. This parameter is the commanded status of the 2-3 shift solenoid. When the TCM commands first or second gear, the scan tool should display ON. When the TCM commands third or fourth gear, the scan tool should display OFF.

Accelerator Pedal Posit: Scan tool displays a range of 0-100 percent. This parameter indicates the position of the accelerator pedal. The value indicated may not correspond to the TP angle value.

Band Apply Solenoid : Displays 0 to 100. This parameter indicates the commanded duty cycle (DC) of the Band Apply Solenoid. The band apply solenoid controls the apply and release rate of the brake band. A 0% duty cycle indicates that the TCM is commanding the band to apply or release with maximum speed and firmness. A 100% duty cycle indicates that the TCM is commanding the band to apply or release with minimum speed and firmness.

Battery Voltage : Displays 0 to 18 volts. This parameter is the battery voltage at the TCM.

Brake Switch : Displays Applied/Released. Indicates the state of the Brake Switch. The TCM uses this input in order to control the TCC operation.

Commanded Gear: Displays 1-2-3-4. This parameter indicates the forward gear that is currently commanded by the TCM.

DTC #1: Displays the current diagnostic trouble code set by the TCM.

DTC #2: Displays the second diagnostic trouble code set by the TCM. More than two codes can be set at one time by the TCM. Refer to DTC history.

Default Mode : Displays Active/Inactive. Inactive indicates that the transmission is operating in normal modes. Active indicates that the transmission control system is operating in the default mode (all of the controlled components are de-energized).

ECT: Displays -40°C to 215°C (-40°F - 419°F). This value represents coolant temperature as sent over the ECM CAN data circuit.

Engine Speed: Displays 0 to 8160 RPM. The engine speed is provided to the TCM from the ECM on the CAN data circuit.

Engine Torque: Displays -100 to 410 N·m(-136 to +548 lb-ft). This value is proportional to engine torque. The ECM provides a torque output value to the TCM.

Engine Torque Reduction: Displays -500 to +10 N·m(6.678-7.4 lb-ft). This parameter indicates the amount of torque reduction being requested. The value will decrease as the torque is reduced.

MIL Request: Displays Active/Inactive. This is the commanded state of the MIL. Active indicates the TCM is requesting MIL illumination and the MIL should be on. Inactive indicates the TCM is not requesting MIL illumination.

Number of DTCs: Displays 1-20. This indicates the quantity of DTCs stored in the TCM.

PC Sol. Actual Current: Displays 0.010 to 1.063 AMPS. This parameter indicates the measured current of the pressure control regulator solenoid circuit at the TCM. 0.10 AMPS (low current flow) indicates that the maximum line pressure is being commanded. 1.1 amps (high current flow) indicates that the minimum line pressure is being commanded.

PRNDL A/B/C/P: Displays High/Low. These parameters are the inputs from the automatic transmission manual shaft shift position switch. High represents a B+ voltage signal and low represents a 0 voltage signal. Inputs A, B, and C feed the decoder section of the TCM. Input P is the parity signal.

Power Relay Status: Displays On/Off. Indicates the commanded state of the output circuit relay. ON indicates the TCM is commanding the relay On. OFF indicates the TCM is commanding the relay Off. The output circuit relay supplies power for the band apply, TCC and shift solenoids.

Shift Pattern Mode: The scan tool displays the following modes.

    • Economy Program -- A manually selectable transmission mode (also the default mode at start up). Provides smooth shifts and shift scheduling tailored for fuel economy.
    • Sport Program -- A manually selectable transmission mode. The Sport Program provides firmer/delayed upshifts for more aggressive performance.
    • Winter Program -- A manually selectable transmission mode. In this mode the transmission will start in 3rd gear in order to improve the traction during slippery conditions.
Sport Mode Lamp : Displays On/Off. This display indicates the commanded state of the sport indicator lamp.

Sport Mode Switch : Displays On/Off. This display indicates the current state of the sport program push button. When you depress the button, this parameter will display On.

TCC Slip Speed : Displays -4064 to +4064 RPM. This parameter indicates the calculated TCC slip speed based on engine speed, commanded gear, and transmission output speed. The TCM verifies the calculation by referencing the commanded state of the TCC solenoid.

TCC Solenoid : Displays On/Off. This parameter indicates the commanded state of the TCC solenoid. On indicates that the TCM is commanding the solenoid ON to apply the TCC. OFF indicates that the TCM is commanding the TCC to release.

TCM Torq. Red. Request: Displays Yes/No. Yes indicates that the transmission is requesting the ECM to reduce the engine torque. No indicates engine torque reduction is not being requested.

TFT Sensor: Displays 0 to 5 Volts. This parameter indicates the measured voltage on the TFT sensor signal circuit to the TCM.

TP Angle: Displays 0-100%. This parameter indicates the amount of throttle opening.

TR Switch --A/B/C/P: Displays On/Off. These parameters are the four inputs from the automatic transmission manual shaft shift position switch. On represents a B+ voltage signal. Off represents a 0 voltage signal. Inputs A, B, and C feed the decoder section of the TCM. Input P is the parity signal.

Trans. Fluid Temp.: Displays -40 to 215°C (-40° to 419°F). The TCM converts the electrical resistance of the TFT sensor into degrees. Transmission temperature is used in order to determine Hot Mode operation.

Transmission OSS : Displays 0 to 8160 RPM. This parameter indicates the rotational speed of the transmission output shaft expressed as revolutions per minute (RPM).

Transmission Range : Displays Park, Reverse, Neutral, Drive, 3rd, 2nd, 1st. Indicates the transmission selector lever position.

Vehicle Speed : Displays a range of 0-248 km/h (0-158 mph). This parameter is the input signal from the vehicle speed sensor assembly to the TCM.

WOT Switch: Displays On/Off. This is the current state of the throttle switch. ON indicates that the measured throttle angle exceeds 89%.

Winter Mode Lamp: Displays On/Off. This display indicates the commanded state of the winter mode lamp.

Winter Mode Switch: Displays On/Off. This display indicates the state of the winter mode push button. When then button is depressed this parameter will display on.