P1401 on your Hyundai can be as simple as a faulty gas cap. We recommend
inspecting the gas cap, and if found faulty go ahead replace it and clear
the trouble code using a trouble code scanner. P1401 means the Tank Leakage
Module has detected a failure. Possible serious faults include:
1 - Open Or Short Circuit Condition; this could indicate a faulty motor.
2 - Poor Electrical Connection; this could indicate defective wiring.
3 - Faulty DMTL Module Faulty
The diagnosis module comprises an electromechanically driven pressure pump
and valve. The computer module measures the pump's electrical current
consumption during the test. The variance of current determines whether the
system is defective or not. In a best case scenario the fault could be a
loose or defective gas cap. In a worst case scenario the fault may be a
defective pump or pressure motor.
We recommend tracing the fuel EVAP system for loose connections, sharp bends
or damage to the fuel vapor lines. Also check for cracks and fuel leakage on
all fuel vapor lines and the EVAP Charcoal canister itself.
