Diagnostic Aids

WARNING: This page is about a different car, the 2003 Lexus LX 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 for pressure switching valve), P0451 (evaporative pressure sensor), P0452 (evaporative pressure sensor low input), or P0453 (evaporative pressure sensor high input) is output after DTC P0442 or P0456, first troubleshoot DTC P0441, P0446, P0451, P0452 or P0453. It no malfunction is detected, troubleshoot DTC P0442 or P0456 next.

Read freeze frame data using hand-held tester or OBD-II scan tool, as freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, this is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, or the air-fuel ratio was lean or rich at the time of the malfunction. When the ENGINE RUN TIME in the freeze frame data is less than 200 seconds, carefully check VSV for EVAP, charcoal canister and vapor pressure sensor.