Test 16 No Self-Test Output

Fig.8 - MCU System Wiring Circuit:

1. Disconnect jumper wire from Self-Test Trigger input circuits 201 and 60.

2. Disconnect harness connector from MCU, then connect a voltmeter between circuit 687 and 60, Fig. 8 of vehicle harness connector and observe voltmeter reading with key on and engine off. If voltage is 10.5 volts or greater, proceed to step 4. If voltage is less than 10.5 volts, proceed to next step.

3. Leave positive lead of voltmeter connected to circuit 687 of harness connector and connect other lead to engine block ground. If voltage is 10.5 volts or more, service circuit 60. If voltage is less than 10.5 volts, service circuit 687.

4. With key off, check circuit 60 pin no. 14 for continuity between Self-Test connector and engine block ground. If resistance is 10 ohms or less, proceed to next step. If resistance is greater than 10 ohms, service circuit 60.

5. Check circuit 201 for continuity between Self-Test connector and vehicle harness connector that mates with MCU pin no. 19. If resistance is 10 ohms or less, continue to next step. If resistance is greater than 10 ohms, service circuit 201.

6. With key off, connect an ohmmeter between tach terminal of coil horseshoe connector and circuit 11 of the vehicle harness connector that mates with the MCU connector pin no. 8 while observing ohmmeter. If resistance is 10 ohms or less, proceed to next step. If resistance is greater than 10 ohms, service circuit 11.

7. Disconnect vehicle harness from CANP solenoid and the MCU. Check circuits 687 and 101 for continuity. If resistance of each circuit is 10 ohms or less, proceed to next step. If resistance of either circuit is greater than 10 ohms, service the circuit.

8. Connect an ohmmeter across the CANP solenoid and observe reading. If resistance is 50-100 ohms, proceed to next step. If resistance is less than 50 ohms or greater than 100 ohms, replace CANP solenoid.

9. Connect one lead of an ohmmeter to engine block ground and other lead to circuit 101 of vehicle harness. If resistance is 1000 ohms or greater, continue to next step. If resistance is less than 1000 ohms, service circuit 101 for short to ground.

10. Check to make sure Canister Purge solenoid passes vacuum when energized and blocks vacuum when de-energized. Also check housing for cracks. If solenoid blocks and passes vacuum as indicated, replace MCU. If solenoid does not pass or block vacuum as indicated or solenoid housing leaks, replace solenoid.