GM Service Manual Online
For 1990-2009 cars only
Cruise Control Active: The scan tool displays Yes or No. The powertrain control module (PCM) determines the current status of the cruise control operation. An operating cruise control system is displayed as Yes.

Cruise On/Off Switch: The scan tool displays On/Off. This is the state of the cruise control On/Off switch as detected by the PCM. An active switch is displayed as On.

Cruise Resume/Accel Switch: The scan tool displays On or Off. This is the state of the resume/accel switch as detected by the PCM. An active cruise resume and accel switch is displayed as On.

Cruise Set/Coast Switch: The scan tool displays On or Off. This is the state of the cruise set switch as detected by the PCM. An active cruise set switch is displayed as On. The cruise control On/Off switch must be On to view the parameter correctly.

Engine Speed: The scan tool displays 0 to 9999 RPM. This is the engine RPM as monitored by the PCM. The PCM monitors the crankshaft position (CKP) signal circuit in order to determine the engine RPM.

Ignition 1 Signal: The scan tool displays 0 to 25.5 volts. The PCM monitors the voltage of the ignition 1 voltage circuit.

Initial Brake Apply Signal: The scan tool displays Applied/Released. The BCM monitors the signal circuit of the brake pedal position sensor. When the PCM receives a GMLAN serial data message from the BCM indicating that the brake pedal has been applied, the scan tool displays Applied.

Reduced Engine Power: The scan tool displays Active or Inactive. When the PCM detects that a reduced engine power condition exists, the scan tool displays Active.

Stop Lamp Pedal Switch: The scan tool displays Applied or Released. The PCM monitors the stop lamp pedal switch signal circuit. An activated brake pedal is displayed as Applied.

Stop Lamp Pedal Switch Signal: The scan tool displays Volts. The PCM monitors the voltage of the stop lamp pedal switch signal circuit.

TAC/PCM Communication Signal: The scan tool displays OK or Fault. The PCM uses the universal asynchronous receiver transmitter (UART) serial data circuit in order to communicate with the throttle actuator control (TAC) module. A malfunction in the UART serial data circuit is displayed as Fault.

TAC Stop Lamp Pedal Switch: The scan tool displays Applied or Released. The TAC module monitors the stop lamp pedal switch signal circuit. An activated brake pedal is displayed as Applied.

TAC Vehicle Speed Signal: The scan tool displays OK or Fault. The TAC module monitors the vehicle speed signal circuit. A malfunction in the vehicle speed signal circuit is displayed as Fault.

Traction Control Status: The scan tool displays Active or Inactive. When the PCM detects that a traction control condition exists, the scan tool displays Active.

Vehicle Speed Circuit History: The scan tool displays OK/Open/Short/Invalid State. The PCM detects and determines the history of the vehicle speed circuit.

Vehicle Speed Circuit Status: The scan tool displays OK/Open/Short. When the PCM detects that a malfunction in the vehicle speed signal circuit exists, the scan tool will display Fault or Invalid State.

Vehicle Speed Sensor: The scan tool displays 0-255 km/h (0-155 mph). The PCM monitors the vehicle speed sensor signal in order to calculate the vehicle speed for display.