Code P1568, Cruise System Problem (SPS Indicated High): Notes

WARNING: This page is about a different car, the 1994 Oldsmobile Ninety-Eight and 1994 Buick Park Avenue. However, it is still accessible from the selected car via links, so may be relevant.

PCM controlled cruise control system is designed to be self monitored to ensure desired cruise servo position and actual cruise servo position are equal to one another. When Code P1568 is set, vehicle may operate in power management mode and Code P1599 will set. While in power management, PCM will shut off fuel to 3 cylinders to avoid over-revving engine in case throttle is being held open by a sticking cruise control throttle cable, brake vacuum release valve, or cruise control servo. Power management may be perceived as a severe engine miss or lack of power. Code P1568 will set when the following conditions are present.

Actual servo position is greater than 15 percent above desired servo position of zero percent.
Above condition met for one second.

When Code P1568 is set, PCM will not allow cruise control operation. Condition that causes Code P1568 may cause vehicle to operate in power management and Code P1599 to set. P1568 does not illuminate the Malfunction Indicator Light (MIL).