Diagnostic Procedures

Connect scan tool. Turn ignition on, engine off. Using scan tool, view malfunction history. If DTC P0452, P0453 or P0460 is set, diagnose affected DTC. If DTCs are not present, go to next step.
Using scan tool, select SPECIAL TEST function and run SERVICE BAY TEST. If test indicates PASS, problem is intermittent. See DIAGNOSTIC AIDS . If test does not indicate PASS, go to next step.
Use EVAP pressure/purge diagnostic station and ultrasound leak detector to locate and repair leak. After repairs, run SERVICE BAY TEST to verify repair.