DTC 611 - Fuel Tank System, Large Leak Or DTC 612 - Fuel Tank System Small Leak

WARNING: This page is about a different car, the 1996 Volvo 850. However, it is still accessible from the selected car via links, so may be relevant.

Check status message on Volvo Scan Tool (998-8686 ). If fault is PERMANENT, LARGE LEAK, go to next step. If fault is INTERMITTENT, LARGE LEAK, perform checks in next step only.
Ensure fuel filler cap seal is intact. Check all fuel lines, including EVAP canister, roll-over valve, fuel pressure regulator, and fuel tank hoses and hose connectors. Repair as necessary. If fuel filler cap seal and fuel hoses are okay, go to next step.
Start and idle engine. Disconnect hose between Canister Purge (CP) valve and EVAP canister from CP valve. Using scan tool, read off CP valve value to determine whether valve is activated. If there is vacuum in CP valve when valve is activated, go to step 5). If there is no vacuum in CP valve when valve is activated, go to next step.
Reconnect hose between Canister Purge (CP) valve and EVAP canister to CP valve. Start and idle engine. Disconnect hose between Canister Purge (CP) valve and CP valve intake manifold. If there is vacuum in hose, replace CP valve. If there is no vacuum in hose, check is hose between CP valve and intake manifold is blocked. Repair as necessary.
Turn ignition off. Remove left front wheelwell. Remove EVAP canister. Connect hose between CP valve and EVAP canister. Using scan tool, read off canister purge valve value to determine whether valve is operating. If there is vacuum in hose when CP valve is activated, go to next step. If there is no vacuum in hose, check for restriction in hose between CP valve and EVAP canister.
Ensure all EVAP canister inlets and outlets are airtight. Repair as necessary. If EVAP canister inlets and outlets are okay, carefully disconnect hose to fuel tank from EVAP canister. Connect vacuum pump to hose. Attempt to pump vacuum. If no vacuum can be created, go to next step. If vacuum can be created, check if roll-over valve is airtight. Also check that hose between fuel tank and EVAP canister is airtight.
NOTE: Following step pressurizes fuel tank. Ensure tank does not contain more than 13 gallons of fuel.
Ensure ignition is off. Clamp hose between CP valve and intake manifold. Ensure fuel tank-to-EVAP hose is connected. Carefully disconnect EVAP canister shut-off valve hose from EVAP canister. Connect Pressure Gauge (999 5646 ) to EVAP canister. Set pressure at 7 kPa. Let pressure build for 5 minutes, ensuring pressure does not increase beyond maximum 10 kPa. Turn off valve. Pressure may drop 1-2 kPa before stabilizing. Read off pressure. Wait 10 minutes.
If pressure does not stabilize, go to step 10). If pressure stabilizes, disconnect pressure gauge. Reconnect EVAP canister hose. Remove hose clamp from hose between CP valve and intake manifold. Start and idle engine. Using scan tool, read off fuel tank pressure and CP valve value. If fuel tank pressure does not drop when CP valve opens, go to next step. If fuel tank pressure drops when CP valve opens, remove left fender housing. Ensure hose and connectors to EVAP cansiter shut-off valve are airtight. Repair as necessary. If hose and connectors are okay, replace EVAP canister shut-off valve.
Turn ignition off. Remove fuel tank pressure sensor located in front of fuel pump. Check all hoses for blockage. Repair as necessary. If hoses are okay, replace fuel tank pressure sensor.
Ensure ignition is off. Pressurize fuel tank as outlined in step 7). Spray soapy water on fuel tank, fuel hoses and other components. It may be necessary to lower fuel tank to gain access to hoses and connectors on top of tank. Repair as necessary.