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Home >> Chevrolet >> 2000 >> Camaro Base, 2D Convertible, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Self-Diagnostics - 3.8L >> Diagnostic Tests >> DTC P0442: EVAP System Small Leak Detected >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
  2. Check for disconnected vacuum or purge lines. Check for loose or missing fuel fill cap. Check if DTC P0443 or P0449 are set. Repair as necessary. If no problem is found, go to next step.
  3. Turn ignition off. Disconnect EVAP canister line from EVAP canister purge valve to relieve fuel tank pressure. Turn ignition on, with engine off. Using scan tool, observe FUEL TANK PRESSURE parameter. If scan tool indicates fuel tank pressure at about zero in. H2O go to next step. If scan tool does not indicate fuel tank pressure at about zero in. H2O, go to step  15.
  4. Zero pressure and vacuum gauges on EVAP Pressure/Purge Diagnostic Station (J-41413). Turn ignition off. Reconnect all previously disconnected EVAP component. Install Fill Tank Cap Adaptor (J-41415-40) between fuel fill neck and fuel filler cap. Connect EVAP pressure/purge diagnostic station to fill tank cap adaptor. Turn ignition on, with engine off. Using scan tool, capture FAIL RECORD DATA for this DTC. Clear DTCs. Using scan tool, select SEAL option to seal EVAP system. Pressurize system to 5 in. Hg by slowly turning EVAP diagnostic station rotary switch to PRESSURE position. Using scan tool, observe fuel tank pressure parameter. If fuel tank pressure is about 5 in. Hg, go to next step. If fuel tank pressure is not about 5 in. Hg, go to step  7.
  5. Turn ignition on, engine off. Using scan tool, command EVAP vent solenoid ON (closed). Using EVAP pressure/purge diagnostic station pressurize EVAP system to 15 in. H2O. Monitor EVAP pressure/purge diagnostic station pressure gauge. Turn EVAP pressure/purge diagnostic station rotary switch to HOLD position. If pressure decreases to less than 10 in. H2O within 2 minutes, go to next step. If pressure does not decrease to less than 10 in. H2O within 2 minutes, see DIAGNOSTIC AIDS .
  6. Disconnect fuel tank vapor and EVAP purge lines from EVAP canister. Plug fuel tank vapor line fitting at EVAP canister. Connect a hand-held vacuum pump to EVAP purge line fitting at EVAP canister. Ensure EVAP vent solenoid is still commanded ON (closed). Attempt to apply 5 in. Hg to EVAP canister. If vacuum is maintained as specified, go to step  9. If vacuum cannot be maintained as specified, go to next step.
  7. Check for restricted fuel tank vapor line or restricted EVAP purge line. Repair as necessary. After repairs, go to step  16. If no problem is found, diagnose using DTC P0452 test. See DTC P0452: FUEL TANK PRESSURE SENSOR CIRCUIT LOW VOLTAGE (EXCEPT GRAND PRIX, IMPALA, MONTE CARLO & REGAL)  or DTC P0452: FUEL TANK PRESSURE SENSOR CIRCUIT LOW VOLTAGE (GRAND PRIX, IMPALA, MONTE CARLO & REGAL) .
  8. Check for damaged fresh air vent hose or damaged EVAP canister. Repair as necessary. After repairs, go to step  16. If no problem is found, go to step  13.
  9. Check for leaking fuel tank vapor line or damaged EVAP purge line. Repair as necessary. After repairs, go to step  16. If no problem is found, go to next step.
  10. Disconnect engine vacuum purge line from EVAP canister purge valve. Connect EVAP diagnostic station vacuum gauge hose to canister side of purge valve. Turn ignition on, with engine off. Using scan tool, select SEAL option to seal EVAP system. Operate engine at 1200-1500 RPM and observe vacuum level. If vacuum level is about zero in. Hg, go to step  12. If vacuum level is not about zero in. Hg, go to next step.
  11. Replace EVAP canister purge valve. After replacing purge valve, go to step  16.
  12. Reconnect all previously disconnected EVAP components. Using scan tool, select SEAL option to seal EVAP system. With EVAP pressure/purge diagnostic station connected to EVAP service port, attempt to pressurize EVAP system to 15 in. Hg by leaving diagnostic station control knob in PRESSURIZE position. Using Ultrasonic Leak Detector (J-41416), locate and repair EVAP system leak. It may be necessary to lower fuel tank to check connections at top of tank. After repairs, go to step  16.
  13. Replace EVAP vent valve. After replacing vent valve, go to step  16.
  14. Check for kinked or restricted canister purge line between EVAP canister purge valve and canister. After replacing purge valve, go to step  16.
  15. Turn ignition off. Remove EVAP canister line from fuel tank or EVAP canister to relieve fuel tank pressure. Turn ignition on, with engine off. Using scan tool, observe fuel tank pressure parameter. If fuel tank pressure is about zero in. Hg, go to step  14. If fuel tank pressure is not about zero in. Hg, diagnose using DTC P0453. See DTC P0453: FUEL TANK PRESSURE SENSOR CIRCUIT HIGH VOLTAGE .
  16. Turn ignition on, engine off. Using scan tool, command EVAP vent solenoid on (closed). Using EVAP pressure/purge diagnostic station pressurize EVAP system to 15 in. H2O. Monitor diagnostic station pressure gauge. Turn EVAP pressure/purge diagnostic station rotary switch to HOLD position. If pressure decreases to less than 10 in. H2O within 2 minutes, repeat step  3. If pressure does not decrease to less than 10 in. H2O within 2 minutes, system is okay.
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