September 3, 2023

Fixing P0497 in a 2006 Honda Accord

This code is "evaporative control system malfunction".

The code is also described as "low purge flow" -- this is probably flow from the canister to the intake, but I am not clear on this yet, or where the sensor is that would detect this.

This is a system intended to control the release of gas tank vapors into the atmosphere.

Round 1 - replace the gas cap

I have seen this before and the fix was to replace the gas cap! I am trying this again.
It did not work. I replaced the cap, cleared the codes, and let my wife drive the car. I checked the next morning and P0497 is back. As I learn more, I find that a leaky gas cap will usually set a different code, but could set the P0497.

Charcoal canister and purge valve

Other things to check are the solenoid purge valve, as well as the tubing that connects it to the gas tank. Also check the wiring. The valve is in the engine compartment. It is mounted to the driver side of the intake manifold with two 10mm bolts. It has two hoses and an electrical connection.

The charcoal canister collects fuel vapors and can get clogged up. The canister is back near the gas tank, more or less below the driver side rear door. A big plastic shield covers the underside of the vehicle. Working on this would be much easier with the car up on a rack.

Take it to the shop

Here is the lesson up front. If you have any ideas, try them first. I balked at buying a purge valve for $90 because I wasn't sure if it would fix it. I took it to the shop (Primarily Japanese in 9-2023) and payed them $725 -- to replace the purge valve! Here is the breakdown: 
$155 - diagnose the CEL
$240 - parts (purge valve)
$60  - new gas cap with tether
$130 - labor for purge valve
$65  - diagnose cooling fan motor inoperative
$42  - shop supplies / hazmat
No telling what the shop supplies were, but there are always shop supplies. I had replaced the gas cap with an autozone replacement, but they say it was not sealing. I was warned about this online. Or did they just try this first and when it did not work replace the purge valve? Or do they just do this on a P0497 to avoid any customer returns.

I could have taken the internet advice and gone to the Honda dealer for a new gas cap. And here are prices for the purge valve: 

Rock Auto - Dorman $47
Rock Auto - WVE $75
Rock Auto - Standar motor $91
Parts Geek - Dorman $90
Parts Geek - Standard motor $84
Parts Geek sells round "universal" radiator fans for $80. I'll need to troubleshoot to find out if it is the fan motor, or relay, or wiring. I can get a whole drop in fan assembly for $100. A dual assembly from TRQ costs $102, while a single fan is $80, well that seems clear.
Have any comments? Questions? Drop me a line!

Tom's Camry pages / tom@mmto.org