GM Service Manual Online
For 1990-2009 cars only

Circuit Description


Object Number: 901645  Size: MF

DTC P1584 will set if the powertrain control module (PCM) disengages the cruise. Normal driver induced commands such as brake ON/OFF, cruise switch ON/OFF, etc., will not set this DTC. However, it is possible for a driver to induce this DTC with abnormal driving maneuvers. An example would be shifting from D4 to neutral while the circuit is engaged.

Conditions for Setting the DTC

The PCM will disengage the cruise and set DTC P1584 if any of the following conditions are met:

    • The ignition 1 voltage is less than 10 volts or greater than 16 volts DC.
    • The vehicle acceleration is greater than 16 km/h per second (10 mph per second) or traction active.
    • The decel is greater than 6.5 km/h per second (4 mph per second).
    • The speed error, the difference between set speed and actual vehicle speed, is greater than 24 km/h (15 mph) for 10 seconds or greater than 32 km/h (20 mph) instantaneously. It may be caused if on steep hills.
    • The engine speed is out of range RPM if less than 950 or greater than fuel cutoff RPM while in cruise.
    • The gear is out of range, such as invalid gear ratio selection for cruise.
    • The Park/Neutral switch possible failure on automatic transaxles only.

Testing

Important: If DTC P1640 or P1641 are present, diagnose these first.

Use of the malfunction history records in the scan tool parameter will help diagnose driver induced versus system failures. Inspect the Disable bits at the bottom of the malfunction table, such as Disable PRNDL Fail, Disable Volt Out Of Range, etc. Did the failed parameter pass since failure? Has it failed since DTC clear, this ignition cycle?