Preliminary Checks

NOTE: Prior to performing any diagnostics or engine related testing, perform all preliminary tests first. Set all adjustments to specifications listed on vehicle emissions decal.

On all vehicles, check idle speed with automatic transmissions in "DRIVE" position (if equipped) and ensure correct idle RPM is obtained. Ensure ignition timing is set to proper specification.
Disconnect throttle switch harness connector, exhaust gas sensor connector and install a 2500 ohm resistor into the temperature sensor circuit with sensor disconnected.
Ensure that CO levels are acceptable by confirming that the Red LED light flashes in Mode 2 with all systems in tact.
Maintain idle speed at middle engine speed (approximately 2000 RPM). Green inspection light should flash 5 or more times in 10 seconds in Mode 1.

Perform an idle speed switch test. Idle speed should increase to the amount specified in the IDLE SWITCH SPEED INCREASES chart when idle speed switch is turned from "OFF" to "ON" position. If idle is not as specified, adjust accordingly.

IDLE SWITCH SPEED INCREASES

RPM (A/T) In Neutral	RPM (M/T)	RPM +/-
250	250	150

Perform a test drive to evaluate the effectiveness of any adjustments that may have been made. On all models, if any driveability problems still exist, see DRIVEABILITY/SYSTEM INSPECTION CHARTS .
A test drive to determine if any remaining problems exist.
If the results of the test drive are unsatisfactory (codes are presented), refer to the applicable DRIVEABILITY/SYSTEM INSPECTION CHARTS .
After all replacements and/or repairs are completed, test drive the vehicle to evaluate the vehicles performance after the diagnosis and repair procedure is completed.