GM Service Manual Online
For 1990-2009 cars only

Scan Tool Data Definitions Disengage History

One of the following conditions must be present in order for a disengagement parameter to appear:

    • The Cruise Control System is active and disengagement is requested.
    • The engagement of the Cruise Control System is requested while a fault is present.
Accel Rate: The engine control module (ECM) detects that the vehicle acceleration is greater than the calibrated cruise control threshold.

APP Override: The ECM detects that the accelerator pedal overrides the set vehicle speed for approximately 60 seconds.

Brake: The ECM detects that the stop lamps have been activated according to the brake pedal position (BPP) sensor / stop lamp switch input from the platform module. Also, the brake pedal being applied according to the brake fluid pressure sensor input can also set this disengagement reason with vehicles equipped with the vehicle stability enhancement system (VSES).

BPP Data: The ECM detects an invalid brake pedal apply serial data message from the platform module.

BPP DTC: The ECM detects that DTC P0703 is active.

Cancel: The ECM detects that the cruise control cancel switch has been activated.

Clutch: The ECM detects that the clutch pedal switch has been activated.

Coast Disengage: When the ECM detects that the cruise set/coast signal is active and the throttle blade fully closes the cruise control system will disengage until the ECM detects that the set/coast signal is inactive. The cruise control system will then engage and set with the new vehicle speed.

Coast Speed Low: The ECM detects that the Set/Coast switch is activated until the vehicle speed is below 37 km/h (23 mph).

Cruise S/W: The ECM detects that a cruise control software execution error is present.

Cruise Sw Data: A fault in the serial data circuit from the cruise control switch to the platform module is detected.

Cruise Sw. Off: The ECM detects that the cruise On/Off switch was turned to OFF when the cruise control system was enabled.

D Whl Spd Low: The ECM detects the driven wheels are at a slower speed than the non-driven wheels.

D Whl Spd Hi: The ECM detects the driven wheels are at a faster speed than the non-driven wheels.

Decel Rate: The ECM detects that the vehicle deceleration is greater than the calibrated cruise control threshold.

DLC Override: The ECM detects that a DLC override has occurred.

DTC Set: The ECM detects that a DTC has been set which affects the cruise control operation.

ECM Inhibit: The ECM detects a RAM corruption associated to the cruise control system.

ECT Overtemp: The ECM detects the engine temperature is above the calibrated threshold.

Engine Run Time: The ECM detects that the cruise control system has been requested and the engine run time counter is not active.

Engine Speed: The ECM detects that the engine speed is less than or greater than a calibrated RPM.

First Gear: While the cruise control system is active, the ECM detects that the transmission is in Drive 1.

High Speed: The ECM detects that the vehicle speed is greater than the calibrated amount.

High Voltage: The ECM detects that the ignition voltage is above 16 volts.

Illegal Mode: The ECM detects that the acceleration mode is active without the activation of the Accel. switch.

Lost Fwd Gear: The ECM detects that transmission is in Neutral, Reverse or Park.

Low Speed: The ECM detects that the vehicle speed is less than 37 km/h (23 mph) while the cruise control system was enabled.

Low Voltage: The ECM detects that the ignition voltage is below 9 volts.

Memory DTC: The ECM detects an internal memory fault.

MPH Limit: The ECM detects the vehicle is over speed and that the fuel shutoff has been activated.

None: This parameter is displayed when a new ECM has been installed.

Over Set Speed: The ECM detects the current vehicle speed is greater than the set vehicle speed by more than a calibrated amount.

Park Brake: ECM detects the park brake switch is active.

Pedal Initialize: The ECM detects that a stop lamp pedal activation had not occurred before the cruise control system was requested.

PTO Active: The ECM detects power take off is active.

RPM Limit: The ECM detects the engine is over speed and that the fuel shutoff has been activated.

S/C On - Speed High: The ECM detects the Set/Coast switch is briefly applied while the current vehicle speed is greater than the set vehicle speed by more than a calibrated amount.

Simul SC/RA Sw: The ECM detects that the Set/Coast switch and the Resume/Accel switch are active at the same time.

Sw Invalid: The ECM detects the analog cruise control switch input is out of the normal voltage range.

TAC Inhibit: The ECM detects a fault within the throttle actuator control (TAC) system.

TCS: The ECM detects that the traction control system had been activated. It is also possible that a tire with low air pressure can also set this disengagement reason.

Trans. DTC: The ECM detects a transmission gear fault.

Under Set Speed: The ECM detects that the vehicle speed is less than the cruise memory speed by more than a calibrated amount.

VSES: The ECM detects that the vehicle stability enhancement system had been activated.

Scan Tool Data Definitions Cruise Control

The Scan Tool Data Definitions contains a brief description of all cruise control related parameters available on the scan tool. On vehicles equipped with a 3.8L engine, a powertrain control module (PCM) is used. On vehicles equipped with a 4.6L engine, an engine control module (ECM) is used.

BPP Circuit Signal: The scan tool displays Applied or Released. This is the state of the BPP circuit as detected by the ECM.

Cruise Cancel Switch: The scan tool displays Active or Inactive. This is the state of the cruise cancel switch as detected by the ECM.

Cruise Control Active: The scan tool displays Yes or No. The ECM/PCM determines the current status of the cruise control operation. An operating cruise control system is displayed as Yes.

Cruise Control Switch (3.8L): The scan tool displays Off/On/Error/Resume/Set. The body control module (BCM) monitors the cruise control set/coast and resume/accel switch signal circuit in order to determine the status of the cruise control switch.

Cruise Control Switch (4.6L): The scan tool displays Off/On/Error/Resume/Set. The ECM monitors the cruise control set/coast and resume/accel switch signal circuit in order to determine the status of the cruise control switch.

Cruise Disengage (1-6) History: The scan tool displays the last 6 reasons why the cruise control system was disengaged. Refer to the Scan Tool Data Definitions (Disengage History) for descriptions.

Cruise Disengage (1-8) History: The scan tool displays the last 8 reasons why the cruise control system was disengaged. Refer to the Scan Tool Data Definitions (Disengage History) for descriptions.

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

Cruise Resume/Accel. Switch: The scan tool displays Active, Inactive or Invalid. This is the state of the resume/accel switch as detected by the ECM. An active cruise resume/accel switch is displayed as Active.

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/accel switch is displayed as On.

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

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 in order to view the parameter correctly.

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

Ext. Travel BPP Signal: The scan tool displays Applied, Released or Invalid. The state of the BPP signal as determined by the ECM.

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

Initial Brake Apply Signal: The scan tool displays Applied or Released. The PCM monitors the signal circuit of the brake pedal position sensor.

Moderate Brake Apply Signal: The scan tool displays Applied or Released. The PCM monitors the signal circuit of the brake pedal position sensor.

Reduced Engine Power: The scan tool displays Yes or No. When the ECM detects that a reduced engine power condition exists, the scan tool displays Yes.

Stoplamp 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.

Stoplamp 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 Stoplamp 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/Fault/Invalid State. 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 ECM/PCM monitors the vehicle speed sensor signal in order to calculate the vehicle speed for display.