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Test 9, Vacuum Circuit

  1. Ensure no cracks or other damage to actuator vacuum hose(s) exist. Replace vacuum hose(s) as necessary and go to next step.
  2. Turn ignition off. Locate vacuum switch near brake power booster. See Figure. Disconnect vacuum switch 2-pin connector. Check for continuity between ground and vacuum switch connector terminal No. 2 (White/Black wire). If continuity exists, go to next step. If continuity does not exist, repair faulty ground connection or open in White/Black wire between vacuum switch connector and ground.
  3. Check vacuum switch. See VACUUM SWITCH TEST  under COMPONENT TESTING. Replace vacuum switch as necessary. If vacuum switch is okay, disconnect vacuum pump connector. Check for continuity between ground and terminal No. 2 (White/Black wire). If continuity exists, go to next step. If continuity does not exist, locate and repair open in White/Black wire between ground and vacuum pump connector.
  4. Check vacuum pump. See VACUUM PUMP TEST  under COMPONENT TESTING. Replace vacuum pump as necessary. If vacuum pump is okay, reconnect vacuum switch and vacuum pump connectors and go to next step.
  5. Turn ignition off. Disconnect CC ECU connector. Check for continuity between ground and CC ECU connector terminal No. 11 (Red wire). If continuity exists, go to next step. If continuity does not exist, repair open in Red wire between CC ECU connector and vacuum switch connector.
  6. Start engine and let idle. Check for continuity between ground and CC ECU connector terminal No. 11 (Red wire). If continuity does not exist, turn engine off and go to next step. If continuity exists, turn engine off. Locate and repair short in Red wire between CC ECU connector and vacuum switch connector.
  7. Check for continuity between ground and CC ECU connector terminal No. 2 (Red/White wire). If continuity exists, go to next step. If continuity does not exist, repair open in Red/White wire between CC ECU connector and vacuum pump connector.
  8. Disconnect vacuum pump 2-pin connector. Check for continuity between ground and CC ECU connector terminal No. 2 (Red/White wire). If continuity does not exist, replace CC ECU and recheck system operation. If continuity exists, repair short in Red/White wire between CC ECU connector and vacuum pump connector.
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