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Test TC-161A - EVAP Leak Monitor Large Leak Detected

NOTE: For connector terminal ID, see CONNECTOR IDENTIFICATION DIRECTORY. For component location see wiring diagram in the WIRING DIAGRAMS article.
WARNING: Before proceeding with diagnosis, the following precautions must be followed: keep lighted cigarettes, sparks, flames or other ignition sources away from test area. Ensure test area is well ventilated. Ensure fuel tank is at least 1/2 full before performing test. Pressurizing fuel tank with less than 3 gallons of fuel may result in an explosion caused by ignition of fumes. Wear safety glasses when performing test procedures. If vehicle is not being tested on a hoist, ensure parking brake is applied and all wheels are blocked before starting test.
  1. DTC may be set by defective secondary seal on fuel filler neck, or a loose or missing fuel tank cap. Ensure fuel tank is at least 1/2 full. Go to next step.
  2. Connect a hand-held vacuum pump to Leak Detection Pump (LDP) vacuum tee. Apply 18 in. Hg of vacuum to LDP. If LDP does not hold vacuum, repair LDP vacuum supply line and repeat this test to verify repair. If LDP holds vacuum, go to next step.
  3. Turn ignition on. Using scan tool, actuate LDP. If LDP vacuum does not drop during actuation, replace LDP and repeat this test to verify repair. If LDP vacuum drops, go to next step.
  4. Using Evaporative (EVAP) System Testing Kit (6872A) and instructions printed on its cover, perform pressure pump self-test. Go to next step.
  5. Connect EVAP system pressure pump supply hose to Leak Detection Pump (LDP) test port. Set pressure hold to OPEN. Disconnect purge solenoid connector and set vent to CLOSED. Go to next step.
  6. While monitoring vacuum gauge, turn pump timer on. If LDP vacuum decreases more than 8 in. H2O in 2 minutes, go to step 9). If vacuum does not decrease more than 8 in. H2O in 2 minutes, go to next step.
  7. Condition required to set DTC is not present at this time. EVAP SYSTEM GROSS LEAK DTC sets if a leak larger than .080" exists in EVAP system. Possible causes are: defective LDP or a leak larger than .080" in EVAP system. Go to next step.
  8. Inspect all related hoses, wiring and connectors for damage. Repair hoses, wiring and connectors as necessary and perform TEST VER-5A. If hoses, wiring and connectors are okay, see INACTIVE DTC CONDITION. Test is complete. Perform TEST VER-5A.
  9. Set pressure hold to OPEN and set vent to CLOSED. Turn pump timer on. Move EVAP system testing kit away from vehicle to prevent operating noise from interfering with test procedures. Turn pump timer off and go to next step.
  10. Using Ultrasonic Leak Detector (300), check for leaks at fuel tank cap, fuel tank rollover valve, charcoal canister, LDP, and EVAP purge solenoid. Repair or replace leaking component as necessary and perform TEST VER-5A. If no leaks exist, replace LDP and perform TEST VER-5A.
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