Test 4 Vacuum Switch Closed (Code 65)

Fig.10 - Electrical Vacuum Switch Circuit:

1. Make sure that engine is at normal operating temperature and that vacuum hoses are connected to switch.

2. With ignition key off, disconnect vehicle harness from vacuum switch connector. Connect an ohmmeter across midvac switch terminals at switch connector to measure resistance from circuit 213 to 60, Fig. 10. If resistance is greater than 1000 ohms, reconnect hose and proceed to next step. If resistance is 1000 ohms or less, replace switch assembly.

3. Disconnect vehicle harness from MCU. Connect one lead of an ohmmeter to vehicle harness circuit 213 and the other lead to engine block. If resistance is greater than 1000 ohms replace MCU. If resistance is 1000 ohms or less, repair the circuit.