Pcm Code E27 - Open Throttle Switch Circuit: Description

This test monitors ISC throttle switch during coast-down and idle conditions with throttle switch open and brakes applied. Under these conditions, PCM commands ISC to retract and extend, and monitors TP sensor for a corresponding decrease and increase in throttle position.

If PCM does not detect a decrease and increase in throttle position twice in succession, code will set and SERVICE ENGINE SOON light will glow.