What this code means
P1454 may indicate that the EVAP system fuel tank pressure sensor signal is not behaving the way the ECM/PCM expects during EVAP monitoring.
What the vehicle may do
- The check engine light may be on.
- The vehicle may have little or no noticeable drivability change.
- EVAP monitor completion may be affected.
Possible fault areas
- Possible fuel tank pressure sensor signal issue.
- Possible EVAP vent hose blockage or restriction.
- Possible EVAP canister vent shut valve issue.
- Possible EVAP canister restriction or fault.
Diagnostic path
Opening context and first check
On this Civic, P1454 is an EVAP system fault where the ECM/PCM may be seeing fuel tank pressure sensor behavior that does not match what it expects. The vehicle may not have an obvious drivability complaint, but it can set the check engine light, and the possible fault areas often include the fuel tank pressure sensor signal, EVAP venting, vent hoses, the canister vent shut valve, or the canister itself. Start with the basic system checks, and use the actual failure conditions on the vehicle to avoid testing parts of the system that are not likely involved. For the first check, insert the emergency fuel funnel into the fuel filler neck. That funnel is stored in the trunk tool box. Then look at the HDS FTP Sensor value. With the funnel installed, the value should read -0.67 - 0.67 kPa. If it is in range, follow the confirmation path. If it is out of range, move into the fault isolation side of the test. If the branch point is unclear while you are working through the path, pause, recheck the earlier diagnostic path, and avoid guessing.
Confirm the fault under controlled conditions
For confirmation, start the engine and let it idle with no load. On a CVT, use P or N. On a manual transmission, use neutral. Let it run until the radiator fan comes on. Then watch HDS EVAP PC Duty while holding engine speed at 3,000 rpm. Keep EVAP PC Duty at 20 % or more for at least 4 minutes, then let the engine return to idle. After that, monitor OBD status for the target fault and any related EVAP fault status without turning this into a parts call yet. This step is about reproducing the operating conditions and seeing whether the monitor responds the same way again.
Check the EVAP canister vent hose
Next, prepare for the EVAP canister vent hose inspection by disconnecting the EVAP canister vent hose. Check that hose for blockage or restriction. A normal hose has no blockage or restriction. If that check is abnormal, the problem is in the EVAP canister vent hose area.
Check the canister vent shut valve operation
After the vent hose check, remove the EVAP canister vent shut valve for its functional inspection. Connect the 2P connector to the valve, turn the vehicle to ON mode, and command CVS ON with the HDS. Then check the valve operation. A normal valve is free of corrosion and operates properly. If that check is abnormal, the problem is in the EVAP canister vent shut valve area.
Check the FTP sensor vent hose and sensor port
Then move to the FTP sensor vent hose. Disconnect the FTP sensor vent hose and inspect it for blockage or restriction. Normal is no blockage or restriction. If it is abnormal, the problem is in the FTP sensor vent hose area. If that hose checks good, disconnect the FTP sensor vent hose from the FTP sensor. Remove the FTP sensor from the EVAP canister with its connector still connected, then turn the vehicle to ON mode and confirm the HDS FTP Sensor reading. Normal here is -0.67 - 0.67 kPa. If that reading is abnormal at this point, the problem is in the FTP sensor area.
Canister decision and verification
If the previous inspection items all showed normal conditions, the remaining decision in this path is that there is a problem with the EVAP canister. Keep the verification separate from the fault isolation work: after the repair direction is handled, verify the repair and confirm the code stays gone under the proper operating conditions. The takeaway is simple: for P1454, do not jump straight to a part. Confirm the FTP reading, prove the vent path can breathe, prove the valve responds to command, then isolate the sensor side before calling the canister. For more diagnostic training, visit stepdiagnostics.com.
Final check
This diagnosis often comes down to comparing the commanded EVAP behavior with the fuel tank pressure sensor response, then isolating the vent path, valve operation, sensor side, and canister in order.
For more guided automotive diagnostics, visit STEP Diagnostics.
