Inspect the air cleaner and inlet duct. Check all engine vacuum hoses for damage, leaks, cracks, kinks and proper routing. Check Electronic Control (EC) system wiring harness for proper connections, bent or broken pins, corrosion, loose wires and proper routing. Check the powertrain control module (PCM), sensors, and actuators for physical damage.
Basic circuit checks help to minimize pinpoint test steps by providing a procedure to diagnose harness faults associated with the Electronic Engine Control (EC) System:
Open Circuit (Continuity): Disconnect PCM. Measure the harness resistance between the suspect circuit at the harness connector and the appropriate PCM harness connector pin or PCM breakout box (if available). The resistance must be less than 5.0 ohms.
Shorts to Ground: Measure the harness resistance between the suspect circuit at the harness connector and a reliable ground (B-, chassis gnd or PWR GND at the PCM breakout box, if available). The resistance must be greater than 10,000 ohms.
Shorts to Power: Key ON to power up circuit. Measure voltage between the suspect circuit at the harness connector and a reliable ground. The voltage must be less than 1.0 volt.