2005 S60 2.5T Check Engine Light Code P0402

[whistlebird]

Have my used S60 for a month now, and decided to pour a bottle of Techron Fuel System Cleaner in with a tank of Mid-Grade last week.

This afternoon, started the car and went to the supermarket. When I came out, and restarted the car, the Check Engine Light came on,

My code scanner indicated a small leak in the emissions control system P0402. I went to the dealer, and he mentioned that maybe there was a problem with the gas cap. Otherwise, I will have to come back for a full diagnostic. He said it could be so many things.

I replaced the gas cap with a new one by Stant I bought from Pep Boys, erased the code from the computer, and filled up again but this time with BP Premium, NOT Mid-Grade.

I drove the car almost 100 miles today after doing this, and the CEL never came on again(and I stopped and restarted the car several times doing other errands.)

I am thinking that maybe the Techron dislodged something while cleaning or maybe it was just a faulty gas cap. The cap was the original from 9 years ago. Or maybe, it was just poor quality gas, that mid-grade. I experienced this problem once with a Ford and a CEL. After I threw in cleaner, and refueled with Premium, the CEL went out, and never came back on. I do not know if the same theory applies to 2.5T Turbos.

Forgot to mention that I noticed no major performance issues while driving at the beginning when the CEL came on. I did feel as if the engine was running a little rough at first but that seemed to disappear after I changed the cap and filled with Premium.

What do you think? The cap, the gas, or maybe the Turbo Engine is more sensitive to fuel engine cleaners like Techron?

[MoVolvos]

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Usually buy the cleaner from Costco when they have a $7 off on a case of 6. Still have a case in the garage. I use only Chevron Premium at this time at $4.27 Gal: 98 S70 T5 246K, 02 CRV 200K, 03 Odyssey 175K. All the cars do not run well other than Chevron Premium. I have stopped using Costco's Premium also even though it cost me more. I've only had one bad experience with the Techron in the CRV last year.

Sister in law put in lowest grade of Chevron and ran the car with O.D. off for 50 miles on the freeway on a Hot Summer day. Car smell of burnt rubber when she brought it back and was running sluggish. Put in a bottle of Techron and the tailpipe smelled like a skunk a for a month and the CEL was intermittent for a week.

My opinion is that the Techron made the car run too rich as it cleaned the injectors. That being said I just clear that P0402 code on a friend's 05 Civic. Lubricated the gas cap seal with a film of wheel bearing grease and click it 3 times (says that on the Honda gas cap) and it has been a week without the CEL.

Just realized it was not much help because your experience combined both of my scenarios. Try running the car without the gas cap and see if the P0402 comes back on. If it does reset CEL and put cap on correctly and see how it goes?

Blessings,
BKM
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[whistlebird]

I will be driving the car again today, and will see what happens.

I agree with you, I think the Techron, the gasoline, and/or the old gas cap have something to do with the CEL. I bought the car pre-owned, so I really don't know what the previous owner used in it. Moreover the car only had 46k miles, so it wasn't used much in 9 years. Maybe that could have created carbon build-up or similar that triggered the CEL?

Of course, there could definitely be a legitimate Emissions Problem but I am hoping this was just a one time event.

[NC2001v70]

I have had this code on my 2001 V70 and it was intermittant. This code can be due to the gas vapor canister j hose being cracked and leaking. The hose is rubber and even if you don't have a higher milage car, rubber ages dries out cracks up and leaks. It is a short hose about a foot long and I am sure IPD and others stock it fairly inexpensively. On my 2001 v70 the hose and canister is located in a tough area directly above the rear axel and behind the exhaust and exhaust shielding. The hose is not very expensive to buy, but the location for me was a bit annoying as I am just a shade tree mechanic and access was a bit tough to get to both ends of this hose to change it. The sedan versions of the P2 platform from what I understand, have it located closer to the rear passenger wheel well and there may even be an access door under the rear passanger seats on the later versions to make it easier to change this part. Some owners are happy to live with this code until they have to go thru inspection, and can't get it to pass without fixing this from what I have heard, but I do prefer to take problems as they come because I know something else will pop up before too long then you find yourself with a lot more codes to have to solve, and maybe causing loss of performance or worst. Permanet damage!

[abscate]

Long existing threads on this on the inspection issue.

The Feds (EPA) and perhaps your state will allow you to have a couple of drive circuits in "NOT READY" state for inspections, so you don't have to have everything perfect to pass your car.

Every state has their own inspection plan, so you need to check with your inspector to see if s/he follows EPA regs. In NY, they do.