Test 9 - Diagnostic Codes 52, 53, 55, 62, 63 & 65 - Wot
VACUUM SWITCH
- Verify correct amount of vacuum is present at switches (use vacuum gauge). At least 10 in. Hg should be present. If vacuum level is too low, check vacuum lines and thermal switches. If vacuum is okay, go to next step.
- Check switch contacts. Continuity should be present without vacuum. If resistance is greater than 5 ohms, replace vacuum switch(es). If less than 5 ohms, go to next step.
- Check switch contacts with vacuum applied to switches (at least 10 in. Hg). If resistance is less than 5 ohms, replace switch(es). If greater than 5 ohms, go to next step.
- Check continuity from pin 14 in MCU connector to bottom pin in 2-wire connector at vacuum switches (circuit 60). If resistance is less than 5 ohms, go to next step. If greater than 5 ohms, repair wiring.
- Check continuity of switch circuits from MCU connector to switches. Use MCU pins 6, 7 and 18, and appropriate switch connector pin. If resistance is greater than 5 ohms, repair circuit. If less than 5 ohms, go to next step.
- Check same circuit for short to ground. Measure between ground and MCU pins 6, 7 and 18. If resistance is less than 1000 ohms, repair short in circuit. If greater than 1000 ohms, MCU module must be replaced.