Code P027, Open Throttle Position Switch Signal: Notes

Diagnostic test monitors ISC throttle position switch during some coast down and idle conditions with throttle position switch open and brake applied. Under these conditions, PCM commands ISC to retract, and monitors TP sensor for corresponding decrease in throttle position. PCM sets Code P027 if it detects a decrease in throttle position 2 times in succession, throttle is resting on ISC plunger and throttle position should be closed.