Pcm Code E27, Open Throttle Switch CKT: 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 TPS 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.