DTC 4331

^ Open or shorted circuit to carbon canister shut-off valve.

This code may be caused by:

a. Fuse #28 in fuse relay panel blown. If this is the case, codes 2411, 4312, and 4343 should also be present. Check for short to ground in EGR frequency valve, carbon canister frequency valve, carbon canister shut-off valve and/or oxygen sensor heating element.
b. Faulty fuel pump relay (no power to valve).
c. Open circuit between fuse #28 and carbon canister shut-off valve terminal #1 (no power to valve).
d. Open or grounded circuit between carbon canister shut-off valve terminal #2 and ECU terminal 18B.
e. Faulty carbon canister shut-off valve.