DTC P0447/P0448 - EVAP Vent Control Valve Circuit

NOTE: This test is associated with DTC P0447 - EVAP Vent Control Valve Circuit Shorted To Ground and P0448 - EVAP Vent Control Valve Circuit Shorted To Power.

Install scan tool. Start engine and check if DTC P0447 or P0448 is present. If DTC is present, go to next step. If DTC is not present, problem is intermittent. See INTERMITTENTS in TESTS W/O CODES article.
Turn ignition off. Disconnect EVAP vent control valve (located behind front bumper, near horn) harness connector. Turn ignition on. Check voltage between vent control valve harness connector terminal No. 1 and ground. Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check circuit between EVAP vent control valve terminal No. 1 and SFI control relay. See appropriate wiring diagram in WIRING DIAGRAMS article.
Turn ignition off. Disconnect ECM harness connector. Check for continuity between EVAP vent control valve harness connector terminal No. 2 and ECM harness connector terminal No. 18. If continuity is present, replace EVAP vent control valve, then go to next step. If continuity is not present, check circuit between EVAP vent control valve and ECM.
Reconnect ECM and EVAP vent control harness connector. Clear DTC. See CLEARING CODES under Self Diagnostic System section. Retest system. If DTC resets, replace ECM.