This test detects faults in the MCU only.

1. Check Tach lead for a ground short. Leave harness connected to MCU; disconnect coil and ignition module connectors. Measure resistance between ground and self-test connector, then Tach connector. If resistance is less than 1000 ohms, go to step 2). If higher than 1000 ohms, MCU is not shorted.
2. Disconnect harness from MCU and measure resistance again. If resistance is less than 1000, repair circuit. If greater than 1000, replace MCU module.

Fig 1: No Start Test Wiring Diagram