Test TC-160A: EVAP Leak Monitor Small Leak Detected

NOTE: For connector terminal identification, see CONNECTOR IDENTIFICATION . For component location and wiring diagram, see 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.

On all bodies except AB body, go to step 3) . On AB body, use scan tool to read DTCs. If DTC SPECIFIC GOOD TRIPS counter is not displayed or displayed count is not "0", go to next step. If DTC SPECIFIC GOOD TRIPS counter is displayed and displayed count is "0", go to step 3) .
Using scan tool, read and record FREEZE FRAME data. Attempt to duplicate conditions in FREEZE FRAME data. Using scan tool, read DTCs. If DTC SPECIFIC GOOD TRIPS counter changes to "0", go to next step. If DTC SPECIFIC GOOD TRIPS counter does not change to "0", conditions required to set DTC are not present at this time. Operate vehicle for one DTC specific good trip. Erase DTC and perform TEST VER-6A: LEAK DETECTION PUMP (LDP) VERIFICATION .
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.
On AB body, go to step 6) . On all other bodies, 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.
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.
Using Evaporative (EVAP) System Testing Kit (6872A), Adapter Hose (6922) on AB body, and instructions printed on testing kit cover, perform pressure pump self-test. Go to next step.
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.
While monitoring vacuum gauge, turn pump timer on. If LDP vacuum drops more than 6 in. H2O on AB body or 8 in. H2O) on all other bodies, in 2 minutes, go to step 11) . If vacuum does not drop more than specified amount in 2 minutes, go to next step.
Condition required to set DTC is not present at this time. EVAP SYSTEM SMALL LEAK DTC sets if a leak larger than .040" and smaller than .080" exists in EVAP system. Possible causes are: defective LDP or a leak larger than .040" and smaller than .080" in EVAP system. Go to next step.
Inspect all related hoses, wiring and connectors for damage. Repair hoses, wiring and connectors as necessary and perform TEST VER-6A: LEAK DETECTION PUMP (LDP) VERIFICATION . If hoses, wiring and connectors are okay, see INACTIVE DTC CONDITION . Test is complete. Perform TEST VER-6A: LEAK DETECTION PUMP (LDP) VERIFICATION .
Ensure fuel tank is at least 1/2 full. Ensure LDP is still actuating. 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. Go to next step.
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-6A: LEAK DETECTION PUMP (LDP) VERIFICATION . If no leaks exist, replace LDP and perform TEST VER-6A: LEAK DETECTION PUMP (LDP) VERIFICATION .