DTC P1447: EVAP Control System Purge Flow Monitoring: Procedure
- Check EVAP canister for cracks. Replace, if cracked and retest system. If EVAP canister is okay, start engine and warm to normal operating temperature. Turn ignition off. Disconnect EVAP Canister Purge Volume Control Valve (EVAP-CPVCV) hose from EVAP service port. See VACUUM DIAGRAMS article. Start engine and let idle for at least 80 seconds. While quickly increasing engine speed to 2000 RPM, check for vacuum at EVAP-CPVCV hose. Vacuum should exist. If vacuum does not exist, go to next step. If vacuum exists, go to step 3.
- Check vacuum hose and purge port for blockage or leak. Repair as necessary and retest system. If hose is okay, remove EVAP-CPVCV. Using jumper wires, apply battery voltage and ground to EVAP-CPVCV terminals. See Figure. Check for airflow between ports "A" and "B". Air should flow. Remove jumper wires. Air should not flow. If operation is as specified, go to next step. If operation is not as specified, replace EVAP-CPVCV and retest system.
- Check for leak in EVAP-CSPS hose. See Figure. Repair as necessary and retest system. If hose is okay, disconnect EVAP-CSPS harness connector. Inspect connector for water. If water does not exist, go to next step. If water exists, replace EVAP-CSPS and retest system.
- Reconnect all hoses. Start engine and warm to normal operating temperature. Measure voltage between ground and ECM terminal No. 92 (fuel tank temperature sensor signal) by backprobing. See Figure and Figure . Ensure voltage is less than 4.2 volts. Turn ignition off and wait at least 10 seconds. Start engine and wait at least 20 seconds. Select MODE 7 with scan tool. If DTC P0450 is present, replace EVAP-CSPS and retest system. If DTC P0450 is not present, go to next step.
- Check for blockage in hose connected to EVAP-CVCV. See Figure. Clean with compressed air, if necessary and retest system. If hose is okay, remove EVAP-CVCV from EVAP canister. Check for rust in port "B". See Figure. If rust exists, replace EVAP-CVCV and retest system. If rust does not exist, go to next step.
- Using jumper wires, apply battery voltage and ground to EVAP-CVCV terminals. Air should flow between ports "A" and "B". See Figure. Disconnect jumper wires. Air should not flow between ports "A" and "B". EVAP-CVCV should switch in one second or less. If EVAP-CVCV operates as specified, go to step 8. If EVAP-CVCV does not operate as specified, go to next step.
- Clean EVAP-CVCV ports with compressed air and repeat step 6. If EVAP-CVCV is okay, go to next step. If EVAP-CVCV still does not operate as specified, replace EVAP-CVCV and retest system.
- Install all removed parts. Start engine and warm to normal operating temperature. Turn ignition off. Disconnect vacuum hose from throttle opener. See Figure. Using a hand vacuum pump, apply vacuum to throttle opener until throttle opener rod does not contact throttle drum. Disconnect TP switch harness connector. Go to next step.
- Check continuity between TP switch terminals No. 4 and 5. See Figure. With throttle fully closed, continuity should exist. With throttle partially open or fully open, continuity should not exist. If continuity is as specified, go to step 11. If continuity is not as specified, go to next step.
- Adjust TP switch. See ON-VEHICLE ADJUSTMENTS article. Repeat step 9. If continuity is still not as specified, replace TP switch and retest system. If continuity is as specified, go to next step.
- Inspect EVAP purge line for leaks. See VACUUM DIAGRAMS article. Repair as necessary and retest system. If no leaks are found, clean EVAP purge line with compressed air and go to next step.
- No problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.