Cruise Control

The Scan Tool Data Definitions contains a brief description of all cruise control related parameters available on the scan tool.

BPP Status: The scan tool displays trouble Unlearned/Learned/Invalid/Undecided. This is the state of the BPP sensor. The BPP sensor is calibrated correctly and displays Learned.

Brake Pedal Signal Status: The scan tool displays Applied/Released. The ECM monitors the stop lamp pedal switch signal circuit, and displays Applied when the switch is active.

Cruise: The scan tool displays 0-150 Counts. The IPM monitors the cruise control switch signal circuit. The values in the list are obtained from the cruise control switch known of good state. OFF=0 Counts / On=29 Counts / Resume=76 Counts / Set=148 Counts.

Cruise Control Active: The scan tool displays Yes or No. The ECM determines the current status of the cruise control operation. The cruise control system displays Yes when it is Active.

Cruise Control Switch: The scan tool displays On/Off/ Error/Resume/Set. The IPM monitors the cruise control set/coast and accel/resume switch in order to determine the status of the cruise control switch. The IPM sends serial data information to the ECM, indicating the cruise control switch status.

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

Cruise Inhibited: The scan tool displays YES/NO. This is the state of the cruise disabled signal instructions as determined by the ECM. When the ECM disables the cruise control, the cruise disabled signal instruction is displayed as On.

Reasons for Cruise Disabled: The scan tool displays the reasons for the cruise control disabled. The scan tool displays the last 8 reasons why the cruise control was disabled.

Cruise Disabled Signal Instructions: The scan tool displays On/Off. This is the state of the cruise disabled signal instructions as determined by the ECM. When the ECM disables the cruise control, the cruise disabled signal instruction is displayed as On.

Cruise Control On/Off Switch: The scan tool displays On/Off. This is the state of the cruise control on/off switch as detected by the ECM.

Cruise Control Resume/Accel. Switch: The scan tool displays Active/Inactive. The ECM receives GMLAN serial data information sent from the IPM, indicating the state of the cruise control accel./resume switch. An active cruise control Resume/Accel. switch is displayed as Active.

Cruise Set/Coast Switch: The scan tool displays Active/Inactive. The ECM receives GMLAN serial data information sent from the IPM, indicating the state of the cruise control set/coast switch. An active cruise control set/coast switch is displayed as Active. The cruise control On/Off switch must be On in order to view the parameter correctly.

Driver Set Vehicle Speed: The scan tool displays km/h (mph). This is the driver set vehicle speed as monitored by the ECM.

Driver Throttle Overtake Status: The scan tool displays Active/Inactive. The ECM monitors the throttle and reports the throttle overtake conditions as directed by the driver.

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

Initially Brake Applied Signal: The scan tool displays Applied/Released. The IPM monitors the initial signal that the brake pedal has been used. When the engine control module (PCM) receives GMLAN serial data information from the instrument panel module (BCM), indicating the brake pedal has been depressed, the scan tool displays Applied. Before the cruise control system is applied, the engine control module (PCM) must receive GMLAN serial data information from the instrument panel module (IPM), indicating the brake pedal has been depressed.

Brake Slowly Applied Signal: The scan tool displays Applied/Released. This is the state of the brake slowly applied signal as monitored by the ECM.

Parking Brake Switch: The scan tool displays On/Off. The IPM monitors the parking brake switch signal circuit.

Stop Lamp Pedal Switch: The scan tool displays Applied/Released. The ECM monitors the stop lamp pedal switch signal circuit. The active brake pedal is displayed as Applied.

Stop Lamp Relay: The scan tool displays Applied / Released. The ECM monitors the stop lamp pedal switch signal circuit. The active brake pedal is displayed as Applied

Stop Lamp Status: The scan tool displays On/Off. The IPM monitors the brake pedal position switch signal circuit. The active brake pedal is displayed as On.

Traction Control System Status: The scan tool displays Active/Inactive. When the ECM detects the conditions under which the traction control system is initialized, the scan tool displays Active.

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

APP Indicated Angle: This parameter displays the APP angle as calculated by the control module according to the signal of the APP sensor. The APP indicated angle has a range and is displayed as a low percent when the accelerator pedal has not been depressed, as a high percent when the accelerator pedal has been completely depressed.

BPP Circuit Signal: This parameter displays the BPP circuit status as determined by the brake pedal circuit. The scan tool displays Applied when the brake pedal has been depressed, and the scan tool displays Released when the brake pedal has not been depressed.

BPP Signal: This parameter displays the BPP switch status as determined by the brake pedal switch. The scan tool displays Applied when the brake pedal has been depressed, and the scan tool displays Released when the brake pedal has not been depressed.

Cruise Control Active: This parameter displays the cruise control system status as determined by the control module. When the cruise control system controls the vehicle speed, the scan tool will display Yes. When the cruise control system does not work, the scan tool will display No.

Desired Idle Speed: This parameter displays the engine idle speed (RPM) as commanded by the control module. The control module will compensate for diversified engine load in order to maintain the desired engine idle speed. This parameter will be invalid unless the engine runs.

Engine Coolant Temperature Sensor: This parameter displays the engine coolant temperature which is obtained based on the input from the engine coolant temperature sensor. When the coolant temperature is too low, the scan tool will display a low temperature. When the coolant temperature is too high, the scan tool will display a high temperature.

Engine Oil Level Switch: This parameter displays the status of the engine oil level switch as determined by the control module. If the engine oil level is always lower than about 1 quart for a long time, the control module uses this information to turn on the engine oil level Low Oil Indicator. When the engine oil level is too low, the scan tool will display Low. When the engine oil level is correct, the scan tool will display Ok.

Engine Runtime: This parameter displays the duration time since the engine starts to run. The scan tool will display in hour, minute and second. When the engine stops running, the engine runtime will be reset to 0.

Ext. Travel BPP Signal: This parameter displays the brake pedal status as determined by the ext. travel brake pedal switch position. When the brake pedal is depressed more than 40% of the total travel, the scan tool will display Applied.

Ignition 1 Signal: This parameter displays the voltage as measured on Ignition 1 Circuit of the control module. When the ignition switch is at Ignition 1, the control module will be applied with a voltage. When the voltage is low, the scan tool will display a low value. When the voltage is high, the scan tool will display a high value.

Spark: This parameter displays the spark timing as commanded by the control module on the ignition control circuit. If the spark timing is Before Top Dead Center (BTDC) or spark advance, the scan tool will display a negative value; if the spark timing is After Top Dead Center (ATDC) or spark retard, the scan tool will display a positive value. Because the ignition control module sets spark advance at a fixed value BTDC while operating in bypass mode, the displayed spark advance only reflects true spark timing when the PCM has commanded IC mode.

Starter Relay Instructions: The scan tool displays On/Off. The scan tool displays Off and only until the ignition switch is set to CRANK position, does the scan tool display On.

Transmission Control Module (TCM) Request Torque: This parameter displays the amount of torque calculation requested from the controller.

Transmission Control Module (TCM) Torque Increased: This parameter displays if the controller responds to the torque increase request.

Transmission Control Module (TCM) Torque Decreased Active: This parameter displays if the transmission control module is decreasing the torque.

Traction Control System (TCS) Torque Increased: This parameter displays if the controller responds to the torque increase request.

Traction Control System (TCS) Torque Decreased Active: This parameter displays if the electronic braking TCS determines that the torque has been decreased.

Traction Control System (TCS) Torque Transfer Signal: This parameter displays the torque percent from the engine output to the transmission as calculated by the control module. When the torque is high, the scan tool will display a high value, when it is low, it displays a low value.

Traction Control System (TCS) Torque Request Signal: This parameter displays the torque percent required to obtain from the engine to the transmission as calculated by the control module. When the torque is high, the scan tool will display a high value, when it is low, it displays a low value.

Torque Management Spark Retard: This parameter displays the torque to make the ignition spark timing retard as controlled by the control module. Under the extreme torque control conditions (such as wheel spinning), the scan tool will display a high value. Under the low torque control conditions (such as light load driving), the scan tool will display a low value.

Desired Throttle Position Angle: This parameter displays the desired throttle angle as calculated by the Throttle Actuator Control (TAC) module according to the driver instructions. When the accelerator pedal is depressed, the scan tool will display a high value; when the accelerator pedal is released, the scan tool will display a low value.

Indicated Throttle Position Angle: This parameter displays the throttle angle as calculated by the control module based on the signal of the Throttle Position (TP) sensor. The indicated throttle position angle has a range and is displayed as a low percent when the throttle is closed, as a high percent when the throttle is wide open.

Vehicle Speed Circuit Status: This parameter displays the diagnostic state of the vehicle speed circuit output driver. The scan tool will display OK, Incomplete, Open, Short B+, or Short Gnd. OK indicates no circuit failure has been detected in the current test. Incomplete indicates the circuit test has not been completed. Other displays indicate there is a short or open in the circuit/component, while there is no electrical connection between this circuit/component and the control module.

Disengage History

Cruise Control Scan Tool Data Definitions - Disengagement History is a universal list for all the cruise control disengagement definitions on the scan tool. Which one of the cruise control disengagement parameters may be applied on the scan tool is determined by the cruise control system equipped with the vehicle.

One of the above conditions must be present for a disengagement parameter to appear:

Accel Rate: The Powertrain Control Module/Engine Control Module (PCM/ECM) detects that the vehicle acceleration is greater than the calibrated cruise control threshold.

Sequence Error: The PCM/ECM detects that there is an execution error in the cruise control system software.

Brake: The PCM/ECM detects that the stop lamps have been activated, or the PCM/ECM detects that the stop lamp pedal has not been depressed before the cruise control system is requested.

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

Cruise Control Switch Position: The PCM/ECM detects that the acceleration mode is active without the activation of the Accel. switch.

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

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

Cruise Inhibit: The PCM/ECM detects that the cruise control On/Off switch has been disengaged when the cruise control system is activated.

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

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

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

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

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

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

ETC: The PCM/ECM detects that a fault within the throttle actuator control (TAC) system.

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

High Accel. Speed: The PCM/ECM detects that the vehicle acceleration speed is greater than the calibrated cruise control threshold.

High Decel. Speed: The PCM/ECM detects that the vehicle deceleration is greater than the calibrated cruise control threshold.

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

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

Fuel Injector Off: The PCM/ECM detects that the engine is over speed and the fuel shutoff has been operating.

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

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

Manual/Neutral: The PCM/ECM detects that the transmission is at Neutral, Reverse or Parking.

Memory DTC: The PCM/ECM detects an internal memory fault.

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

No History: This parameter is displayed when a new PCM/ECM has been installed.

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

Off: The PCM/ECM detects that the cruise control On/Off switch has been disengaged when the cruise control system is activated.

Over Set Speed: This parameter is displayed when the current over set speed is greater than the calibrated amount.

Overspeed: This parameter is displayed when the current over set speed is greater than the calibrated amount.

Overspeed Click: When the current vehicle overset speed is greater than the calibrated amount, this parameter is displayed so long as the Set/Coast switch is briefly applied.

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

PCM Error: The PPCM/ECM detects that there is an execution error in the cruise control system software.

PCM Disabled: The PCM/ECM detects that an RAM fault related to the cruise control system.

Pedal>Cruise: The PCM/ECM detects that the accelerator pedal override the set vehicle speed for approximately 60 seconds.

Serial Data: A fault in the serial data circuit from the cruise control switch to the chassis module is detected.

S/C On, CC Off: When the PCM/ECM detects that the cruise Set/Coast signal is active and the throttle blade fully closes, the cruise control system will disengage until the PCM/ECM detects that the Set/Coast signal is inactive. The cruise control system will then engage and set with the new vehicle speed.

S/C On - High: When the current vehicle overset speed is greater than the calibrated amount, this parameter is displayed so long as the Set/Coast switch is briefly applied.

Stop Lamp Switch: The PCM/ECM detects that the stop lamp has been activated.

TAC Module Disabled: The PCM/ECM detects that a fault within the throttle actuator control (TAC) system.

Traction Force: The PCM/ECM detects that the traction control system has been activated. It is possible that a tire with low air pressure can also set this disengagement reason.

Loss of Traction Force: The PCM/ECM detects that the traction control system has been activated. It is possible that a tire with low air pressure can also set this disengagement reason.

Two Instructions: The PCM/ECM detects that the Set/Coast switch and the Resume/Accel switch are active at the same time.

Two CC Instructions: The PCM/ECM detects that the Set/Coast switch and the Resume/Accel switch are active at the same time.

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

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