Idle Speed Control (ISC)
| Circuit | ECA Pin | BOB Pin | Wire Color |
|---|---|---|---|
| ISC | 2W | 41 | R/Bk |
| VPWR | 1B | 37, 57 | Y/Bk |
1) Checking System Integrity Visually check all wiring, harnesses, connectors and components for evidence of damage, overheating, shorting or looseness. If a fault is found, repair as necessary. If no faults are found, go to next step.
2) Checking Solenoid Function Install breakout box and leave ECA disconnected. Turn ignition on. Jumper breakout box test pin No. 41 to ground. Listen for clicking sound at solenoid. If clicking sound is heard, ISC solenoid is functioning okay. Fault is in another circuit or ECA. If no clicking sound is heard, go to step 3.
3) Check Voltage To ISC Solenoid Locate ISC solenoid mounted on throttle body. Disconnect solenoid connector. With ignition on, measure voltage between VPWR wire and ground. If voltage reading is less than 10 volts, repair VPWR wire to main relay. If voltage reading is more than 10 volts, go to step 4.
4) Warm to operating temperature. Turn engine off. Measure voltage between ISC solenoid VPWR and ISC wire while cranking engine. Replace solenoid if voltage is more than 10 volts. If voltage is less than 10 volts, go to next step.
5) ISC Circuit Continuity Check With breakout box installed and ECA disconnected, remove solenoid connector. Check for continuity between breakout box pin No. 41 and ISC connector wire. If continuity does not exist, repair ISC (White) wire between solenoid and ECA.
6) If continuity is present, check for continuity between breakout box pin No. 41 and all other test pins. If continuity is found between breakout box pin No. 41 and another test pin(s), ISC wire is shorted to that circuit. Repair as necessary and recheck circuit. If all circuits are okay, replace ECA.