Diagnostic Aids

A cruise control throttle cable which binds or intermittently sticks may cause vehicle to operate in power management and Code P1599 to set. Code P1599 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 P1599.

Fig 1: Code P1599 Schematic (3.8L) Cruise Power Management

Fig 2: Code P1599 Flow Chart (3.8L) Cruise Power Management