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.
Race engine with all systems intact and immediately after engine returns to idle, confirm that both LED lights flash simultaneously in Mode 2.
Maintain idle speed at middle engine speed (approximately 2000 RPM).
While in Mode 2 of diagnostics, confirm simultaneous flashes from Red and Green inspection lights.

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

Model

A/T In Neutral

M/T

RPM +/-

Sentra

⁽¹⁾

⁽¹⁾	Should be in "ON" position at idle and "OFF" position when accelerator pedal is depressed.

Perform a test drive to evaluate the effectiveness of any adjustments that may have been made. If any driveability problems still exist, see DRIVEABILITY/SYSTEM INSPECTION CHARTS .
Perform the Mode 3 Self-Diagnosis, then the Mode 4 Switch On/Off Test Diagnosis and a test drive to determine if intermittent problems exist. Write down any diagnostic codes may which appear.
If the results of the test drive are unsatisfactory (codes are presented), refer to the applicable DRIVEABILITY/SYSTEM INSPECTION CHARTS . For driveability problems, see same.
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.