Diagnostic Aids
WARNING: This page is about a different car, the 2003 Lexus GX 470. However, it is still accessible from the selected car via links, so may be relevant.
- If DTC P0441 (Purge Flow), P0446 (VSV for CCV), P0451, P0452 or P0453 (Evaporative Pressure Sensor) is output with DTC P0442 or P0456, troubleshoot DTC P0441, P0446, P0451, P0452 or P0453 first. If no malfunction is detected, troubleshoot DTC P0442 or P0456 next.
- Ask customer whether, after MIL came on, customer found fuel tank cap loose and tightened it. Also ask customer whether fuel tank cap was loose when refueling. If fuel tank cap was loose, it was cause of DTC. If fuel tank cap was not loose or if customer was not sure if it was loose, troubleshoot by diagnosis and repair. When the ENGINE RUN TIME in the freeze frame data is less than 200 seconds, carefully check the vapor pressure sensor:
- Read freeze frame data using hand-held tester or OBD II scan tool, as freeze frame data records engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether vehicle was running or stopped, engine was warmed up or not, air-fuel ratio was lean or rich, etc. at time of malfunction.