Diagnostic Aids

Most solenoids leak a small amount of vacuum when closed; however, they should not leak enough to allow servo to reach WOT in 15 seconds with vent closed. When vacuum solenoid is forced on, vacuum will vent to atmosphere unless vent valve is stuck closed. Code P1568 may set if cruise control throttle cable binds or intermittently sticks. Code P1568 can also be set by manually compressing cruise servo to raise engine speed. Outside interference such as a CB antenna lead near PCM wiring harness may induce a false SPS signal and set Code P1568.

An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside insulation. Check for:

• Poor Connection Or Damaged Harness

Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection and damaged harness.