Test 8: ASCD Actuator/Pump Check

Check vacuum hose between ASCD actuator and ASCD pump for damage. If damage exist, repair as necessary. If vacuum hose is okay, go to next step.
Check ASCD cable for proper adjustment. See ASCD CABLE under ADJUSTMENTS. If adjustment is okay, go to next step. If adjustment is not within specification, adjust if necessary.
Disconnect vacuum hose from ASCD actuator. Using a hand-held vacuum pump, apply about 6.0" of vacuum to ASCD actuator. ASCD cable should pull throttle drum. Wait 10 seconds and ensure vacuum does not decrease more than 0.4". If operation is as specified, go to next step. If operation is not as specified, replace ASCD actuator.
Disconnect ASCD vacuum hose from ASCD pump and ASCD pump harness connector. Removal of ASCD pump may be necessary. Connect a vacuum gauge to ASCD pump. Using a fused jumper wire, apply 12 volts to terminal No. 1 at ASCD pump connector. See Fig 1. Using another jumper wire, ground appropriate terminal at ASCD pump connector and observe pump operation. See ASCD PUMP OPERATION table. If ASCD pump operates as described, ASCD pump is okay at this time. If ASCD pump does not operate as described, replace ASCD pump.

ASCD PUMP OPERATION

Function

⁽¹⁾ Ground Terminal No.

Operation

Air Valve

Release Valve

Vacuum Motor ⁽²⁾

Run

⁽¹⁾	With 12 volts applied to terminal No. 1.

⁽²⁾	During vacuum motor operation, a minimum of 5.8" Hg of vacuum should be generated.

Fig 1: Testing ASCD Pump

Courtesy of NISSAN MOTOR CO., U.S.A.