GM Service Manual Online
For 1990-2009 cars only

The Engine Scan Tool Data Definitions contains a brief description of all engine related parameters available on the scan tool. The list is in alphabetical order. A given parameter may appear in any one of the data lists. In some cases, the parameter may appear more than once or in more than one data list in order to group certain related parameters together.

APP Average: The scan tool displays 0-125 counts. The TAC module takes the voltages from the 3 APP Sensors, averages the readings and converts the readings into counts. The scan tool displays the average. The average is different on every vehicle.

APP Indicated Angle: The scan tool displays 0-100 percent. The scan tool displays the Accelerator Pedal Position in percentage. When the APP is at rest, the display shows 0 percent. When the APP is fully depressed, the display shows 100 percent.

Clutch Switch: The scan tool displays Applied or Released. When the vehicle clutch pedal is pressed the scan tool display shows applied, and the cruise control will disengage. When the vehicle clutch pedal is released, the scan tool displays Released, and the cruise control can be resumed.

Cruise Control Active: The scan tool displays Yes or No. When the Cruise control switch is in the on position and the Set/Coast switch is activated the scan tool displays YES. When the cruise control switch is in the ON position and the Set/Coast switch is released the scan tool displays NO.

Cruise Resume/Accel: The scan tool displays On or Off. When the Cruise control switch is in the on position and the Resume/Accel switch is activated, the scan tool displays ON. When the Resume/Accel switch is released the scan tool displays OFF.

Cruise Set/Coast: The scan tool displays On or Off. When the Cruise control switch is in the on position and the Set/Coast switch is activated, the scan tool displays ON. When the Set/Coast switch is released the scan tool displays OFF.

Cruise On/Off Switch: The scan tool displays On or Off. When you activate the cruise control switch, the scan tool displays ON. The switch, when in the ON position, sends a signal voltage to the throttle actuator control (TAC) module. This allows all other functions of the cruise control. When you turn off the cruise control switch, the scan tool displays OFF.

Extended Travel Brake Switch: The scan tool displays Applied or Released. This parameter indicates the state of the extended travel brake switch. This switch is normally closed with the brake pedal released. Scan tool displays Released with the brake pedal released. Scan tool displays Applied with the brake pedal applied approximately greater than 40 percent.

PRND Position: The scan tool displays which position the gear shift lever is in.

Reduced Engine Power: The scan tool displays Active or Inactive. The scan tool displays Active when the PCM receives a signal from the TAC module that a throttle actuator control system fault is occurring. The PCM limits the engine power.

Stoplamp Pedal Switch: The scan tool displays Applied or Released. When the brake pedal is depressed, the scan tool displays applied and the stoplamps go on. When the brake pedal is at rest, the scan tool displays Released and the stop lamps go off.

TAC/PCM Communication: The scan tool displays OK or Fault. If the communication between the TAC Module and the PCM is interrupted the scan tool displays Fault. The scan tool displays OK under the normal operating conditions.

TCC Brake Pedal Switch: The scan tool displays Applied or Released. This parameter indicates the state of the TCC/CC brake switch circuit input. Open indicates 0 voltage input (brake switch open, brake pedal applied). Closed indicates a B+ voltage input (brake switch closed, brake pedal released). When you apply the vehicle brakes, the scan tool displays Applied. The torque converter clutch and cruise control disengages. When you release the vehicle brakes, the scan tool displays Released. This allows the cruise control to be resumed and the torque converter clutch to engage.

TCC Enable Solenoid: The scan tool displays Enabled or Disabled. When the PCM applies a voltage to the TCC Enable solenoid the scan tool displays Enabled.

TP Desired Angle: The scan tool displays 0-100 percent. The PCM indicates the desired throttle angle commanded by the vehicle operator.

TP Indicated Angle: The scan tool displays 0-100 percent. The TP Indicated Angle displays in percentage the amount of throttle opening.

Traction Control: The scan tool displays Active or Inactive (If equipped). The scan tool displays active if the PCM receives a signal from the Electronic Brake and Traction control Module (EBTCM) requesting torque reduction during a traction control maneuver.

Transmission Range: Scan tool displays the transaxle gear position.

Vehicle Speed: The scan tool displays km/h and mph. The vehicle speed sensor signal is converted into km/h and mph for display.