GM Service Manual Online
For 1990-2009 cars only

Scan Tool Data Definitions Cruise Control

The distance sensing cruise control (DSCC) module Scan Tool Data Definitions contains a brief description of all adaptive cruise control (ACC) system related parameters available on the scan tool.

ACC Gap Switch: The scan tool displays Inactive/Up/Down. The body control module (BCM) monitors the gap adjustment switch signal circuit. This is the state of the ACC gap switch as detected by the BCM.

ACC Gap Switch: The scan tool displays voltage. The BCM monitors the gap adjustment switch signal circuit. This is the voltage at the gap adjustment switch signal circuit as detected by the BCM.

Alert Indicator Message: The scan tool displays On/Off. This is the state of the alert indicator message as commanded by the DSCC module.

Alignment Error: The scan tool displays Degrees. This is the degree of alignment error of the forward looking sensor (FLS) radar as calculated by the DSCC module.

ACC Amp Audible Alert: The scan tool displays Ready/Not Ready. This is the state of the radio amplifier as detected by the BCM.

Angle to Closest Target: The scan tool displays Degrees. This is the ACC vehicle angle to the closest target as detected by the DSCC module. The DSCC module calculates in degrees the ACC vehicle position relative to the target vehicle.

Auto Alignment Learn Status: The scan tool displays Aligned/Not Aligned. This is the automatic alignment status of the DSCC module.

Automatic Braking Status: The scan tool displays Ready/Not Ready. This is the automatic braking status of the ACC vehicle as detected by the ABS module.

Clean Radar Indicator Message: The scan tool displays On/Off. This is the state of the clean radar indicator message as commanded by the DSCC module.

Cruise Control Active: The scan tool displays Yes/No. The engine control module (ECM) determines the current status of the cruise control On/Off switch operation. An operating cruise control system is displayed as Yes.

Cruise Control Switch: The scan tool displays On/Off/Set/Coast/Resume/Accel./Cancel/Invalid. The BCM sends a GMLAN serial data message to the ECM. This is the cruise control switch status as detected by the ECM.

Cruise Control Switch: The scan tool displays Off/On/Error/Resume/Set. This is the state of the cruise control switch as monitored by the BCM.

Cruise Control Switch: The scan tool displays Volts. This is the voltage at the cruise control switch signal as detected by the BCM.

Cruise Control Sw. to Battery: The scan tool displays percent (%). This is the ratio of the cruise control switch voltage to battery voltage.

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

Cruise Engaged Indicator Message: The scan tool displays On/Off. This is the state of the cruise engaged indicator as commanded by the DSCC module.

Cruise Inhibit Reason: The scan tool displays the reason why cruise control is inhibited. The scan tool displays the last 8 recent reason why cruise control is inhibited.

Cruise Inhibit Signal Command: The scan tool displays On/Off. This is the state of the cruise inhibit signal command as determined by the ECM. When the ECM inhibits cruise control, the cruise inhibit signal command is On.

Cruise On/Off Switch Status: The scan tool displays On/Off. This is the state of the cruise on/off switch as detected by the DSCC module.

Cruise Ready Indicator Message: The scan tool displays On/Off. This is the state of the cruise not ready indicator as commanded by the DSCC module.

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

Driver Throttle Override Status: The scan tool displays Active/Inactive. The ECM monitors the throttle and reports a throttle override condition initiated 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.

Follow Speed: The scan tool displays km/h (mph). This is the following speed as determined by the DSCC module.

Following Distance: The scan tool displays 0-6 counts. This is the driver selected following distance from the gap switch signal as monitored by the BCM.

HUD Virtual Device: The scan tool displays Present/Not Present. This is the state of the head-up display (HUD) as determined by the DSCC module.

Ignition Voltage Signal: The scan tool displays 0-25.5 volts. This is the ignition voltage as detected by the DSCC module.

Initial Brake Apply Signal: The scan tool displays Applied/Released. This is the state of the initial brake apply signal as monitored by the ECM. Initial brake apply signal by the driver stepping on the pedal needs to occur before cruise control is engaged.

Moderate Brake Apply Signal: The scan tool displays Applied/Released. This is the state of the moderate brake apply signal as monitored by the ECM.

Radar Activated: The scan tool displays Yes/No. This is the state of the DSCC module FLS radar. Yes is displayed in the scan tool if the radar is activated.

Range: The scan tool displays meters. This the range of the closest target as detected by the DSCC module.

Service Radar Indicator Message: The scan tool displays On/Off. This is the state of the service radar indicator as commanded by the DSCC module.

Stop Lamp Signal: The scan tool displays On/Off. This is the state of the stop lamp signal as commanded by the DSCC module.

Stop Pedal Switch: The scan tool displays Applied/Released. The ECM monitors the stoplamp pedal switch signal circuit and an active switch will display as applied.

Target Found this Ignition Cycle: The scan tool displays Yes/No. The FLS radar scans the road environment to detect the presence of a vehicle in its path. Yes is displayed if a target is acquired.

Vehicle Ahead Indicator Message: The scan tool displays On/Off. This is the state of the vehicle ahead indicator as commanded by the DSCC module.

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.

Scan Tool Data Definitions Cruise Disengagement

Distance Sensing Cruise Control (DSCC) Module

The distance sensing cruise control (DSCC) module disengages cruise control for various reasons. The DSCC module disengage reasons are available in the scan tool for display when the DSCC module disengages cruise control. When a cruise control disengagement occurs, be sure to view both the DSCC module and engine control module (ECM) cruise disengagement data.

This Scan Tool Data Definition contains a brief description of the DSCC module cruise control disengage parameters available on the scan tool for display. One of the following conditions must be present in order for a disengagement parameter to be displayed:

    • The cruise control system is active and disengagement is requested.
    • The engagement of the cruise control system is requested while a fault is present.
ABS Active: The scan tool displays Yes/No. The DSCC module disengages adaptive cruise control (ACC) function when the ABS is active.

ABS Malfunction: The scan tool displays Yes/No. The DSCC module detects that the ABS system is malfunctioning.

ACC Ready: The scan tool displays Yes/No. The DSCC module detects that ACC may be inhibited and not ready to be activated.

ACC Configuration: The scan tool displays Yes/No. The DSCC module detects the an error exists in the ACC configuration.

Amplifier Not Ready: The scan tool displays Yes/No. The DSCC module detects that the audio amplifier is not active or is malfunctioning.

Brakes Overheated: The scan tool displays Yes/No. The DSCC module detects that the vehicle brake system is overheating.

Cruise Control Malfunction: The scan tool displays Yes/No. The DSCC module detects that a malfunction exists in the DSCC module.

Cruise Control Switch Malfunction: The scan tool displays Yes/No. The DSCC module detects that a cruise control switch malfunction exists in the ACC system.

HUD Malfunction: The scan tool displays Yes/No. The DSCC module detects that the head-up display (HUD) is not available or is malfunctioning.

Internal DSCC Overtemp: The scan tool displays Yes/No. The DSCC module internal overtemperature occurs.

Invalid Vehicle Speed: The scan tool displays Yes/No. The DSCC module detects that the vehicle speed is invalid.

Radar Needs Cleaning: The scan tool displays Yes/No. The DSCC module detects an forward looking sensor (FLS) radar blockage or malfunction.

Engine Control Module (ECM)

The ECM disengages cruise control for various reasons. A list of all the reasons why the ECM disengages cruise control is available on the scan tool for display should a cruise control disengagement occur. The scan tool retains and only displays in the ECM Cruise Disengage History, the 8 most recent reasons for cruise control disengagement. It is important to note that in the ACC system, the DSCC module also provides to the scan tool reasons for cruise control disengagement separate from the ECM list. Refer to Distance Sensing Cruise Control (DSCC) Module.

This Scan Tool Data Definition contains a brief description of the ECM cruise control disengage parameters available on the scan tool for display. One of the following conditions must be present in order for a disengagement parameter to be displayed:

    • 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 ECM detects that the vehicle acceleration is greater than the calibrated cruise control threshold.

Bad Sequence: The ECM detects that a cruise control software execution error is present.

Brake: The ECM detects that the stop lamps have been activated or the ECM detects that a stop lamp pedal activation had not occurred before the cruise control system was requested.

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

CC Sw. Position: The ECM detects that the acceleration mode is active without the activation of the Accel. switch.

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

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

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.

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

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

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.

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

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

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

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

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

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

Injector Disable: The ECM detects that the engine is overspeed and that the fuel shutoff has been activated.

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.

Manual/Neutral: The ECM detects that transmission is in Neutral, Reverse or Park.

Memory Corrupt: An internal ECM memory fault is detected.

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

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

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

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

Over Set Speed: This parameter is displayed when the current vehicle speed is greater than the set vehicle speed by more than a calibrated amount.

Over Speed: This parameter is displayed when the current vehicle speed is greater than the set vehicle speed by more than a calibrated amount.

Over Speed Tap: This parameter is displayed when 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.

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

PCM Error: The ECM detects that a cruise control software execution error is present.

PCM Inhibit: The ECM detects a random access memory (RAM) corruption associated to the cruise control system.

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

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

S/C On, CC Off: 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.

S/C On -- Speed High: This parameter is displayed when 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.

Stop Lamp Switch: The ECM detects that the stop lamps have been activated.

TAC Inhibit: The ECM detects a fault within the TAC system.

Traction: 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.

Traction Loss: 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.

Two Commands: The ECM detects that the set/coast switch and the resume/accel switch are active at the same time.

Two CC Commands: The ECM detects that the set/coast switch and the resume/accel switch are active at the same time.

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

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