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Home >> Suzuki >> 2001 >> XL-7 Limited >> Repair and Diagnosis >> External Pages >> Different car >> Section 5 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0442: Evaporative Emissions System - Small Leak Detected >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2002 Isuzu Trooper. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform ON-BOARD DIAGNOSTIC II SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD-II system check, go to next step.
  2. Turn ignition off. Remove fuel cap. Turn ignition on. Using scan tool, read FUEL TANK PRESSURE parameter. If scan tool displays 1.51 volts, reinstall fuel cap and go to next step. If scan tool display is not as specified, go to DTC P0452: FUEL TANK PRESSURE SENSOR LOW VOLTAGE  or DTC P0453: FUEL TANK PRESSURE SENSOR HIGH VOLTAGE  .
  3. Using scan tool, read and record FAIL RECORDS data for DTC P0442. Clear DTCs. Connect EVAP pressure/purge cart to EVAP service port. Zero pressure and vacuum gauges on EVAP Pressure/Purge Cart (J41413) or equivalent. From scan tool, command EVAP canister vent valve ON (closed). Using EVAP pressure/purge cart, pressurize EVAP system until FUEL TANK PRESSURE reading is 1.47 volts. On scan tool, observe FUEL TANK PRESSURE parameter. If parameter reads 1.47 volts, go to next step. If parameter does not read 1.47 volts, go to DTC P0452: FUEL TANK PRESSURE SENSOR LOW VOLTAGE  or DTC P0453: FUEL TANK PRESSURE SENSOR HIGH VOLTAGE  .
  4. Start engine and allow to idle. Using scan tool, command EVAP canister vent valve ON (closed). Using EVAP pressure/purge cart pressurize EVAP system to 15 in. H2 O. Turn EVAP pressure/purge cart rotary switch to HOLD position. Monitor EVAP pressure/purge cart pressure gauge. If FUEL TANK PRESSURE reading drops to less than 1.47-1.51 volts within 2 minutes, go to next step. If FUEL TANK PRESSURE reading does not decrease as specified, check for an intermittent problem. See DIAGNOSTIC AIDS .
  5. Turn ignition off. Disconnect fuel tank vapor and EVAP purge lines from EVAP canister. EVAP canister is attached to frame rail under rear of vehicle. Plug fuel tank vapor line fitting at EVAP canister. Connect a hand vacuum pump to EVAP purge line fitting at EVAP canister. Using scan tool, ensure EVAP canister purge valve is still commanded ON (closed). Attempt to apply vacuum to EVAP canister until FUEL TANK PRESSURE parameter on scan tool reads 1.46 volts. If FUEL TANK PRESSURE reading is maintained as specified, go to step  8. If FUEL TANK PRESSURE reading can not be maintained as specified, go to next step.
  6. Check if vent hose is disconnected or damaged. Check EVAP canister for damage. If a problem is found, repair as necessary. After repair, go to step  10. If no problem is found, go to next step.
  7. Replace EVAP canister vent valve. After repair, go to step  10.
  8. Check for missing or faulty fuel cap. Check for disconnected or leaking fuel tank vapor line. Check for disconnected or damaged EVAP purge line. If a problem is found, repair as necessary. After repair, go to step  10. If no problem is found, go to next step.
  9. Using scan tool, command EVAP canister vent valve ON (closed). With EVAP pressure/purge cart connected to EVAP service port, attempt to pressurize EVAP system by leaving EVAP pressure/purge cart control knob in PRESSURIZE position. Using Ultrasonic Leak Detector (J41416), locate and repair EVAP system leak. It may be necessary to lower fuel tank to check connections at top of tank. After repair, go to next step.
  10. Turn ignition on. Using scan tool, command EVAP canister vent valve ON (closed). Using EVAP pressure/purge cart, pressurize EVAP system to 15 in. H2 O. Turn EVAP pressure/purge cart rotary switch to HOLD position. Monitor EVAP pressure/purge cart pressure gauge. If FUEL TANK PRESSURE reading drops to less than 2.14 volts within 2 minutes, repeat test starting in step  2. If pressure does not decrease, repair is complete.
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