Ecu Circuits
- Locate ECU at right kick panel. Unplug both ECU harness connectors. Turn ignition on. Ensure 12 volts are present at terminal No. one. Ensure terminal No. 2 has continuity to ground.
- Connect a tachometer between terminal No. 12 and ground. Start engine. Tachometer should indicate engine RPM.
- Using jumper wires, connect one jumper wire between terminals No. one and 4. Connect the other jumper wire between terminals No. 2 and 5. Start engine. If engine speed increases to 1600-2400 RPM, ACV is okay. If not, check wiring and ACV.
- Repair or replace any defective components or circuits. Remove jumper wires. Connect all harness connectors. Check to see if idle speed control system is working. If not, ensure all connectors are clean and tight. If no problems are found, replace ECU.
Courtesy of VOLVO CARS CORPORATION