Test 11 Idle Speed Incorrect

Fig.8 - MCU System Wiring Circuit:

1. Check carburetor idle speed adjustments and correct as necessary. Retest.

2. Check vacuum lines between throttle kicker solenoid and actuator for leaks, obstructions or incorrect routing. Correct as necessary and retest.

3. If throttle kicker is vacuum actuated, check manifold vacuum at line to throttle kicker solenoid with engine idling. If there is vacuum, turn key off and proceed to next step. If there is no vacuum, check vacuum line for leaks, blockage, or incorrect routing, then retest.

4. Check throttle actuator for proper operation. Apply at least 10 inches Hg vacuum to actuator vacuum line. If actuator arm extends and holds, proceed to next step. If not, check actuator. Service or replace as necessary and retest.

5. Check throttle kicker solenoid resistance with harness disconnected. If resistance is 45-90 ohms, proceed to next step. If resistance is less than 45 ohms or greater than 90 ohms, replace solenoid and retest.

6. Check circuits between throttle kicker relay connector and throttle kicker solenoid and between solenoid and ground for continuity, Fig. 8. If resistance is less than 10 ohms, proceed to next step. If resistance is greater than 10 ohms, repair circuit.

7. Check circuits 69 and 687 for continuity between MCU and throttle kicker. If resistance is less than 10, proceed to step 9. If resistance is greater than 10 ohms, repair open circuit and retest.

8. Check circuit 69 for isolation from ground with MCU and relay disconnected. If resistance is less than 1,000 ohms, proceed to next step. If resistance is greater than 1,000 ohms, repair grounded circuit 69 and retest.

9. Check throttle relay function when energized. Disconnect MCU connector and turn A/C off. With solenoid connected to harness, connect voltmeter across solenoid terminals. Ground circuit 69 at MCU connector pin 12 and observe voltage. If voltage is less than 10 volts, replace relay and retest. If voltage is greater than 10 volts, replace MCU and retest.