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 ACM also provides to the scan tool reasons for cruise control disengagement separate from the ECM list. Refer to DSCC Data List .

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.