Checking EVAP System
- Turn ignition off. Disconnect EVAP purge solenoid vacuum hoses. EVAP purge solenoid is located on lower right side of engine compartment, near radiator. See Fig 1. Connect a vacuum gauge to the vacuum side of disconnected EVAP purge solenoid vacuum hose. Start engine and observe the vacuum gauge. If vacuum reading is more than 13 in. Hg, go to next step. If vacuum reading is 13 in. Hg or less, repair vacuum hose or vacuum source as necessary.
- Using a vacuum pump, apply 10 in. Hg to EVAP purge solenoid vacuum source port. If vacuum holds, go to next step. If vacuum does not hold, replace EVAP canister purge solenoid valve.
- Ensure 10 in. Hg of vacuum is still applied to EVAP purge solenoid vacuum source port. Turn ignition on. Using scan tool, actuate EVAP purge solenoid and observe vacuum gauge. If vacuum reading decreases, go to next step. If vacuum reading stays unchanged, replace EVAP purge solenoid.
- Turn ignition off. Ensure EVAP purge solenoid vacuum hoses are disconnected. Disconnect the vacuum hose from the EVAP canister and install a vacuum gauge to the disconnected vacuum hose. All models are equipped with 2 EVAP canisters. EVAP canisters are located on frame rail, directly below the driver's seat. See Fig 2. Using a piece of extra hose, connect one end of hose to vacuum source and connect other end of hose to disconnected vacuum hose (hose that goes to EVAP canister) at EVAP purge solenoid. Start engine and observe the vacuum gauge. If vacuum reading is more than 13 in. Hg, go to next step. If vacuum reading is 13 in. Hg or less, repair or replace the vacuum hose between the EVAP canister and the EVAP purge solenoid.
- Turn ignition off. Remove vacuum gauge and reconnect vacuum hose at the EVAP canister. Disconnect EVAP canister outlet hose (hose that goes to fuel tank) from the EVAP canister. Connect a vacuum gauge to EVAP canister outlet port on the EVAP canister. Plug the EVAP canister vent hose. See Fig 3. Using a piece of extra hose, connect one end of hose to vacuum source and connect other end of hose to disconnected vacuum hose (hose that goes to EVAP canister) at EVAP purge solenoid. Start engine and observe the vacuum gauge. If vacuum reading is more than 13 in. Hg, go to next step. If vacuum reading is 13 in. Hg or less, check for a restricted or damaged EVAP canister vent hose. Repair or replace vent hose as necessary. If vent hose is okay, replace EVAP canister.
- Inspect the EVAP canister outlet hose between the fuel tank and EVAP canister. Check for damaged or restricted hose. Replace outlet hose as necessary. If outlet hose is okay, no problem is indicated at this time. Test is complete.
Courtesy of DAIMLERCHRYSLER CORPORATION
Courtesy of DAIMLERCHRYSLER CORPORATION
Courtesy of DAIMLERCHRYSLER CORPORATION