Idle Speed Control (ISC) System (Samurai)
- Warm engine to normal operating temperature. See if Code 12 is present in self-diagnostics. See TESTS W/CODES article. If Code 12 is present, proceed to step 2). If Code 12 was not present, see INITIAL DIAGNOSTIC PROCEDURE in TESTS W/CODES article.
- Ensure idle speed and ISC duty are within specification. See ADJUSTMENTS article. If idle speed and ISC duty is correct, system is operating correctly. If idle speed is correct, but ISC duty is not correct, go to step 3). If idle speed is high, go to step 4). If idle speed is low, go to step 7).
- If idle speed is correct, but ISC duty is incorrect, adjust ISC duty. See ADJUSTMENTS
article.NOTE: When ISC is almost closed, check air intake system for vacuum leaks. If no vacuum leaks are present, adjust ISC duty. If ISC duty remains unchanged when adjusting screw is rotated, check wiring circuit of duty check terminal. For information on duty check terminal, see TESTS W/CODES article.
- If idle speed is high, pinch upper hose on ISC solenoid closed. See Fig 1 . The ISC solenoid is located on right side of engine, near valve cover. Note if engine speed decreases. If engine speed did not decrease, go to step 6). If engine speed decreased, go to step 5).
- Turn ignition off. Disconnect electrical connector from ISC solenoid. Using ohmmeter, check resistance between ISC solenoid terminals. Resistance should be 30-33 ohms. Replace ISC if defective. If resistance was okay, check for short in Light Green/Black wire. See Fig 1 . If wiring is okay, substitute ECM and recheck.
- Ensure no vacuum leaks are present in the air intake system and/or A/C Vacuum Switching Valve (VSV). Adjust idle speed and ISC duty. See ADJUSTMENTS article. If idle speed cannot be adjusted, check air valve. See SYSTEM/COMP TESTS article.
- If idle speed is low, disconnect ISC solenoid hose from air cleaner. Note if air is being drawn into the hose. If no air is being drawn in, go to step 8). If air is being drawn in, adjust idle speed and ISC duty. See ADJUSTMENTS article.
- Turn ignition off. Disconnect electrical connector from ISC solenoid. Using ohmmeter, check resistance between ISC solenoid terminals. Resistance should be 30-33 ohms. Replace ISC if defective. If resistance was okay, go to next step.
- Check for open in Light Green/Black wire, defective wiring connections or clogged hoses to ISC solenoid. See Fig 1 . If all are okay, substitute ECM and recheck operation.