Advanced Diagnostics

DTC P145D: Evaporative Emission (EVAP) System Purge Flow Malfunction (Jet Purge)










General Description
The fuel vapor in the fuel tank is stored in the canister temporarily and introduced into the engine through the evaporative emission (EVAP) canister purge valve. The powertrain control module (PCM) controls the vapor amount introduced in the engine by duty cycling the EVAP canister purge valve.

[Purge flow confirmation] When the pulse of the EVAP canister purge valve cycling is detected by the fuel tank pressure (FTP) sensor by the purge flow (pulse method), the EVAP canister purge valve cycles normally (EVAP canister purge valve OPEN OK) and detects that the purge flow is normal.
- Purge flow is confirmed at each area of negative and positive manifold pressure, and when either area is abnormal, it is determined that there is an abnormality such as a loose or clogged purge line detected.
- When both negative and positive manifold pressure areas are abnormal, it is determined as an abnormality of the purge line or the EVAP canister purge valve opening.

[Abnormal part check] When there is no pulse, there is either no purge flow or the EVAP canister purge valve is stuck open.

[Abnormal purge flow] When the condition of non-return valve A is abnormal, the detected abnormality is because of reverse flow.

- Purge flow check at boost area -

[Purge flow check] The EVAP canister purge valve cycles normally (EVAP canister purge valve OPEN OK) and detects that the purge flow is normal when the pulse of the EVAP canister purge valve cycling is transmitted to the FTP sensor by the purge flow (pulse method).

OK determination: Pulse exists (P145D OK)
- P145A Purge flow OK
- P0496 EVAP canister purge valve stuck Open check OK

NG determination: No pulse (P145D)
- Either purge flow P145A abnormality or P0496 EVAP canister purge valve stuck OPEN failure.
- In this case, When the purge flow check at P145C negative pressure area is determined as OK, or when P0496 EVAP canister purge valve is judged as normal according to the check after the ignition is turned off, after P145C is determined as abnormal, P145A boost area purge flow abnormality is determined.

- When P0496 is determined as normal after the ignition is turned off, determination of the P145C is also implemented after the ignition is turned off.

[Purge flow reverse flow failure P145B] When the non-return valve A fails, boost pressure flows back to the tank side during purge control at boost. At this time, the pulse wave of the FTP sensor is reversed from the normal phase. Time difference of the phase is calculated to determine the purge flow failure.




Monitor Execution Sequence, Duration, DTC Type, OBD Status




Enable Conditions

Malfunction Threshold
The pulse from the fuel tank pressure sensor is 0.1 % or less for at least 13 seconds (boost area).

Confirmation Procedure with the HDS
Do the EVAP FUNCTION TEST in the INSPECTION MENU with the HDS.

Driving Pattern
1. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on.
2. Let the engine idle for at least 59 seconds.
3. Supercharging condition shall be accumulating and drive for at least 13 seconds or more.
4. Turn off the ignition for at least 10 seconds.

Diagnosis Details

Conditions for illuminating the MIL
When a malfunction is detected during the first drive cycle, a Temporary DTC is stored in the PCM memory. If the malfunction recurs during the next (second) drive cycle, the MIL comes on and the DTC and the freeze frame data are stored.

Conditions for clearing the MIL
The MIL will be cleared if the malfunction does not recur during three consecutive trips in which the diagnostic runs.

The MIL, the DTC, the Temporary DTC, and the freeze frame data can be cleared by using the scan tool Clear command or by disconnecting the battery.