Test Conditions

PCM Codes E021, E022 and E024 not set. Vehicle in coast down condition. Throttle switch open, brakes applied, throttle angle 16.5 degrees or less and RPM greater than desired.

Under these conditions, PCM commands ISC to retract and extend and monitors TPS for a corresponding decrease and increase in throttle position. If PCM detects a decrease and increase in throttle position twice in succession, code will set and SERVICE ENGINE SOON light will turn on.