Code P0497, low purge flow

Good afternoon,

The code is for the canister purge valve under the hood.

https://www.2carpros.com/articles/evap-system-code-repair

The easiest way to check it is to remove the electrical connector from the valve, remove the hose that goes to the fuel tank and with the engine running, see if you feel vacuum at the open port of the valve.

Roy

DTC P0497: EVAP System Low Purge Flow

Special Tools Required
Vacuum/pressure gauge, 0 - 4 in.Hg, 07JAZ-001000B
Vacuum pump/gauge, 0 - 30 in.Hg, Snap-on YA4000A or equivalent, commercially available

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.

1. Check the fuel fill cap installation.

Is the fuel fill cap installed and properly tightened?

YES - Go to step 2.

NO - Properly install the fuel fill cap (the cap must say "Tighten to click"). If should turn 1/4 turn after it's tight, then go to step 23.

2. Turn the ignition switch ON (II).
3. Clear the DTC with the HDS.
4. Do the EVAP FUNCTION TEST in the INSPECTION MENU with the HDS.

Is the result OK?

YES - Intermittent failure, system is OK at this time, Check for poor connections or loose terminals at the FTP sensor, the EVAP canister purge valve, or the EVAP canister vent shut valve and the ECM/PCM.

NO - Go to step 5.

5. Check for a loose or damaged EVAP canister purge line between the intake manifold and the EVAP canister purge valve.

Is the line OK?

YES - Go to step 6.

NO - Reconnect or repair the EVAP canister purge line, then go to step 23.


imageOpen In New TabZoom/Print

6. Disconnect the vacuum hose (A) from the EVAP canister purge valve joint (B) in the engine compartment, and connect a T-fitting (C) from the vacuum gauge and the vacuum pump/gauge, 0 - 30 in.Hg, to the vacuum hose (A) as shown.
7. Do the EVAP PCS on in the inspection menu with the HDS.
8. Slowly apply about 0.6 in.Hg (15 mmHg) of vacuum to the hose.

Does it hold vacuum?

YES - Check for blockage in the PCS line between the intake manifold and the EVAP canister purge valve, and the line between the EVAP canister purge valve and the EVAP canister purge joint. If the vacuum hoses are OK, replace the EVAP canister purge valve, then go to step 22.

NO - Go to step 9.

9. Reconnect the vacuum hose to the EVAP canister purge joint.


imageOpen In New TabZoom/Print

10. Disconnect the vacuum hose from the EVAP canister purge line (EVAP canister side), and connect a T-fitting (A) from the vacuum gauge and the vacuum pump/gauge, 0 - 30 in.Kg, to the hose as shown.
11. Do the EVAP PCS ON in the INSPECTION MENU with the HDS.
12. Slowly apply about 2 kPa (0.6 in.Hg, 15 mmHg) of vacuum to the hose.

Does it hold vacuum?

YES - Check for a restricted EVAP canister purge line between the EVAP canister purge valve and the EVAP canister, then go to step 22.

NO - Go to step 13.

13. Remove the FTP sensor with its connector connected.


imageOpen In New TabZoom/Print

14. Connect a T-fitting (A) from the vacuum gauge and a commercially available vacuum pump/gauge, 0 - 30 in.Hg, to the FTP sensor (B) as shown.
15. Check and record the FTP SENSOR reading in the DATA LIST with the HDS.
16. Slowly apply about 1.3 kPa (0.4 in.Hg, 10 mmHg) of vacuum to the hose.
17. Check the FTP SENSOR in the DATA LIST with the HDS.

Is the difference more than 1.1 kPa (0.31 in.Hg, 8 mmHg) before and after applying vacuum?

YES - Go to step 18.

NO - Replace the FTP sensor, then go to step 22.

18. Reconnect the vacuum hoses to the EVAP canister purge line (EVAP canister side), and reinstall the FTP sensor.


imageOpen In New TabZoom/Print

19. Disconnect the vacuum hose (purge line) (A) from the EVAP canister purge valve (B), and connect a T-fitting (C) from the vacuum gauge and the vacuum pump/gauge, 0 - 30 in.Hg, to the hose as shown.
20. Do the EVAP CVS ON in the INSPECTION MENU with the HDS.
21. Slowly apply about 2 kPa (0.6 in.Hg, 15 mmHg) of vacuum to the hose.

Does the hose hold vacuum?

YES - Check for blockage on the EVAP canister purge joint, then go to step 22.

NO - Replace the EVAP canister vent shut valve, then go to step 22.

22. Reconnect all hoses.
23. Turn the ignition switch ON (II).
24. Reset the ECM/PCM with the HDS.
25. Do the ECM/PCM idle learn procedure. See: Engine Control Module > Programming and Relearning
26. Do the EVAP function test in the inspection menu with the HDS.

Is the result OK?

YES - Troubleshooting is complete.

NO - Check for poor connections or loose terminals at the FTP sensor, the EVAP canister purge valve, or the EVAP canister vent shut valve and the ECM/PCM, then go to step 1.

I do not have a vacuum gauge. What is a HDS? Hand held diagnostic tool? When all this first started I had a check fuel cap message. I replaced fuel cap with a Honda cap from the dealership. Still received fuel cap message months later. I always tighten cap until it clicks multiple times. I’ve thought about replacing the purge solenoid valve under the hood but hesitate because the Honda valve is over $100.00. A repair shop close to home said they would do a smoke test first and then go from there. A smoke test is $200.00.

You need no special tools at all.

Follow what I suggested with disconnection the hose to the tank and the electrical connector. Then put your finger over the open port and tell me if you have vacuum.

Do not worry about the fuel cap at this point.

Roy

Sorry I haven’t gotten back to you. I have had to take my Mom to the doctor. I will try and see if I have vacuum at the valve either tomorrow or first of the week.

Sounds like a plan.

We will be here for you.

Roy

I disconnected the electrical plug to the evap purge valve under hood. I removed bottom hose that goes to the gas tank. Cranked car and there wasn’t any vacuum at open port. I did drive the car 400+ miles yesterday. Check engine light did not come on. Whatever the problem is seems intermittent.

You needed to check it with the engine running, not cranking.

See if it comes back on.

Roy

Engine was running.

Was there or did you feel any vacuum?

Roy

No vacuum felt.

Okay, then I would suspect the vent solenoid as the issue.

Roy

Is that located underneath car near gas tank? This is different from purge solenoid, right?

I’m not sure if you are talking about the evap purge valve under the hood or the canister shut valve located under the car.

The purge valve under the hood is what you checked.

The vent solenoid is the canister vent solenoid. It is a normally open valve so you can add fuel. It closes when the ECM does its test of the evap system.

When it does not close and seal, it causes a leak and sets the code.

Roy