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Home >> Isuzu >> 2000 >> Rodeo LSE, 2.2 D >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - 2.2L >> Diagnostic Trouble Code Identification >> DTC P0446: EVAP System Vent Control Circuit Malfunction >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform On-Board Diagnostic II (OBD-II) system check. See SELF-DIAGNOSTICS - INTRODUCTION article. Go to next step.
  2. Diagnose DTC P0461, P0462 or P0463, if set. See appropriate testing procedure. Go to DTC P0461: FUEL LEVEL SENSOR CIRCUIT RANGE PERFORMANCE , DTC P0462: FUEL LEVEL SENSOR LOW INPUT  or DTC P0463: FUEL LEVEL SENSOR HIGH INPUT  . If specified DTCs are not set, go to next step.
  3. Using scan tool, command EVAP canister purge control valve and vent solenoid on and off. Ensure purge valve and vent solenoid make a click when commanded on and off with scan tool. If click is heard, go to next step. If no click is heard, inspect components and verify PCM output signal to each component. See PIN VOLTAGE CHARTS article.
  4. Turn ignition off. Remove fuel cap. Turn ignition on. Using scan tool, read fuel tank pressure value. If reading is 1.51 volts, go to step  7. If reading is not as specified, go to next step.
  5. If battery has been disconnected, perform a visual and physical inspection of EVAP system. Repair as necessary. Record and clear DTCs from memory. Test drive vehicle. Refer to test procedures for any DTC(s) set. If no DTC sets, problem may be an intermittent condition. If battery was not disconnected, go to next step.
  6. Disconnect battery. Wait at least 20 seconds. Reconnect battery and go to step  3.
    NOTE: Calibrate EVAP pressure/vacuum gauges before proceeding. See manufacturer's operating instructions.
  7. Install fuel cap. Using scan tool, command the EVAP vent solenoid ON (closed). Connect EVAP pressure/vacuum gauge to EVAP service port. Attempt to pressurize the EVAP system to 5 in. H2 O. If scan tool FUEL TANK PRESSURE reading is between 1.52-1.69 volts, go to next step. If scan tool reading is not as specified, locate leak in EVAP system using a leak detector.
    NOTE: Review temperature variation instructions included with EVAP Diagnostic Station pressure and vacuum gauge operating instructions before proceeding.
  8. Maintain specified EVAP pressure. Using scan tool, command EVAP vent solenoid off (open) while observing pressure/vacuum gauge. If EVAP system returns to 0 in. H2 O within 5 seconds, see DIAGNOSTIC AIDS . If reading does not return as specified, go to next step.
  9. Disconnect the large vent hose (marked AIR) from EVAP canister. Switch EVAP Diagnostic Station to PURGE. Start engine and bring to normal operating temperature. While holding engine at 2500 RPM, observe diagnostic Station vacuum gauge for 5 seconds. If reading remains less than 30 in. H2 O, go to next step. If reading is not as specified, go to step  12.
  10. Inspect EVAP vent hose between EVAP canister and EVAP vent solenoid for kinks, binding or a restriction. If such condition is found, repair as necessary and go to step  13. If vent hose is okay, go to next step.
  11. Replace EVAP vent solenoid. Go to step  13.
  12. Replace EVAP canister. Go to next step.
  13. Using scan tool, command EVAP vent solenoid ON (closed). Using EVAP Diagnostic Station pressurize EVAP system to 5 in. H2 O. Place EVAP Diagnostic Station to HOLD position. While observing pressure gauge of EVAP Diagnostic Station, command EVAP vent solenoid OFF (open). IF the EVAP system pressure returns to 5 in. H2 O within 5 seconds, system is okay. If EVAP system will not return to 5 in H2 O, go to step  3.
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