Advanced Diagnostics

Advanced Diagnostics - 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) canister and drawn into the engine through the EVAP canister purge valve. The powertrain control module (PCM) controls the amount of vapor introduced into the engine by varying the duty cycle of the EVAP canister purge valve according to the condition of the engine.

[STEP 1]
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 during 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 failed part according to [STEP 2].

[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

Monitor Execution, Sequence, Duration, DTC Type, OBD Status






Enable Conditions






Malfunction Threshold
The output from the FTP sensor is 0.2 kPa (0.07 inHg, 2 mmHg) or less for at least 10 seconds.

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 P or N) until the radiator fan comes on.
2. Let the engine idle for at least 64 seconds.
3. Turn the ignition switch to LOCK (0) for at least 10 seconds.

Diagnosis Details

Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on and a Confirmed DTC and the freeze data are stored.

Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the battery.