Code 18
- Connect diagnostic readout box to the engine harness connector. Place carburetor switch in the open position. Turn ignition switch to the "RUN" position. Place "Read/Hold" switch in the "Hold" position. Code 55 should appear on display of readout box.
- Connect voltmeter to the Black wire of the carburetor 6-wire connector and ground. Press and hold the ATM button until test code 98 appears on the display. If voltmeter reading is pulsating and the solenoid is clicking, check for a poor connection in the harness circuit.
- If voltmeter is not pulsating buts reads within one volt of battery voltage, go to step 4). If voltmeter is not pulsating but reads 0-1 volt, disconnect the computer 14-wire connector. If voltage is now within one volt of battery, replace computer. If not, go to step 5).
- Check V.O.S. control solenoid control circuit. Turn ignition switch off. Disconnect computer 14-wire connector. Connect voltmeter to cavity No. 8 of the 14-wire connector and ground. Turn ignition to the "RUN" position. If voltmeter reads within one volt of battery voltage, replace computer. If voltage is not okay, repair wire of cavity No. 8 for an open circuit to the V.O.S. control solenoid.
- With carburetor 6-wire connector disconnected, connect a voltmeter to the Blue wire of the harness 6-wire connector and ground. Turn ignition switch to the "RUN" position. If voltmeter reads within one volt of battery voltage, repair the Black and White tracer wire of the V.O.S. solenoid to the computer for a short circuit to ground. If 0 volts, check Blue wire for an open circuit to the ignition switch.