Home/Lexus/LX/Lexus LX J100 (1998-2002)/Repair manual/Testing & Diagnostics/DTC P0450: EVAP PRESSURE SENSOR CIRCUIT OR DTC P0451: EVAP …
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DTC P0450: EVAP PRESSURE SENSOR CIRCUIT OR DTC P0451: EVAP PRESSURE SENSOR RANGE/PERFORMANCE Lexus LX J100

CAUTIONIf ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. If ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION.

Circuit Description

Vapor pressure sensor and vapor pressure sensor Vacuum Switching Valve (VSV) are used to detect faults in EVAP system. DTC is set if vapor pressure sensor malfunctions. Possible causes are

  1. Vapor pressure sensor circuit is open or shorted.
  2. Defective vapor pressure sensor.
  3. Defective ECM.

Diagnostic Aids

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.