Ground Circuits
- Turn ignition off. Using an ohmmeter, check for continuity between ground and ECU terminals No. 5 and 10. Resistance should be zero ohms. If resistance is not zero ohms, repair open circuit between ECU connector and ground.
- Connect voltmeter negative lead to ground. Connect positive lead to ECU ground terminals as in step 1). With vehicle running, voltmeter should indicate less than 1 volt. If voltmeter reading is greater than 1 volt, check for open, corrosion or loose connection in ground circuit.