Note On Intermittents

Ensure ISC plunger is depressed when throttle linkage contacts stop screw. Check ISC jumper connector, engine-to-dash connector and PCM connector for improperly crimped or backed-out terminals.

Fig 1: PCM Code E27, Schematic, Idle Speed Control Ckt Problem

Courtesy of GENERAL MOTORS CORP.

Fig 2: PCM Code E27, Flow Chart, Idle Speed Control Ckt Problem

Courtesy of GENERAL MOTORS CORP.

Fig 3: PCM Code E27