DTC P0497: Evaporative Emission (EVAP) System Low Purge Flow Detected: General Description

The fuel vapor in the fuel tank is temporarily stored in the evaporative emission (EVAP) and introduced in the engine through the EVAP canister purge valve. The engine control module (ECM)/powertrain control module (PCM) controls the amount of vapor introduced into the engine by varying the duty cycle to the EVAP canister purge valve according to the condition of the engine.

The EVAP canister purge valve opens normally (EVAP canister purge valve OPEN OK) and detects that the purge flow is normal when the pulse of the EVAP canister purge valve duty cycle is transmitted to the fuel tank pressure (FTP) sensor by the purge flow (pulse method).

OK determination: Pulse exists (P145C OK)

P0497 Purge flow OK
P0496 EVAP canister purge valve stuck Open OK

NG determination: No pulse (P145C NG)

Either purge flow P0497 abnormality or P0496 EVAP canister purge valve OPEN failure.
In this case, classify the failure part according to <STEP 2>.

If there is no pulse, it is determined as either no purge flow or the EVAP canister purge valve is stuck OPEN:

When the FTP sensor fluctuates from negative pressure to atmospheric pressure after the ignition switch is turned to LOCK (0): P0496 EVAP canister purge valve stuck OPEN

When there is no fluctuation of the FTP sensor: P0497 purge flow NG