Volkswagen Passat Forum banner
1 - 6 of 6 Posts

·
Registered
04 Passat 1.8 turbo
Joined
·
13 Posts
Discussion Starter · #1 ·
Hey I have a 04 Passat 1.8liter turbo just went Thur inspection and they told me I have a po456 code and the weird thing is I don’t have a check engine light on any help why this is
 

·
Moderator/Administrator
Joined
·
25,477 Posts
That generally will not kick off a CEL. It can mean a bad seal on the gas cap, cracked plastic evap line to the back of the car, incorrectly installed gas cap, tear in a rubber hose junction in the evap system, etc.

Clear the code and go on your merry way. It may or may not come back. If it does, then you'll do some more looking. I've gotten it maybe 5-6 times over the past 15 years. Its been a couple years since the last time.
 

·
Registered
04 Passat 1.8 turbo
Joined
·
13 Posts
Discussion Starter · #3 ·
What is the po456 p same thing when I scanned it it came up with a po456 and a po456 p I cleared it and then just the po456p came back
 

·
Moderator/Administrator
Joined
·
25,477 Posts
OK, now you need to do some looking. The P may mean pending which means it needs to run another leak detection test for it to fully clear. Do some more driving after clearing and see if it turns into a hard code. If it does set, follow on below.


This happens when the ecu runs a leak detection cycle. It turns on the leak detection pump in the left rear wheel well to pressurize the evap system and fuel tank. If it detects a loss of pressure over a determined amount of time, it will trigger a code for a leak. Very small, small, large....

Your EVAP system starts at the clicking electronic valve on top of the air box. It leads back thru the front fender and underneath the car along the frame rail to the charcoal canister in the spare tire well area. It is a vinyl/coated aluminum pipe and is run along with the fuel line to the rear. If there is a leak anywhere in that circuit, it will trigger that code.

Sometimes, reseating the gas cap or buying a new cap solves it. Another test it to pull off the hose evap hose from the purge valve on the airbox, plug the hose, and cap off the port on the valve.
 

·
Registered
04 Passat 1.8 turbo
Joined
·
13 Posts
Discussion Starter · #5 ·
Thankyou for all ur help going to try a new gas cap 1st then I’ll proceed on to next step
 

·
Registered
04 Passat 1.8 turbo
Joined
·
13 Posts
Discussion Starter · #6 ·
Let me ask you would that code cause a random hard start if there was a leak it’s on gave me a hard start 2time ina year or so
 
1 - 6 of 6 Posts
Top