CEL vanished?

Post by **benweekes** » 04 Apr 2009, 15:39

Hi,I have 1999 v70xc around 130,000 on the car.The cel had been on for about a month now had the code pulled.It was the catalyst below threshold bank 1.From what I know usually means vaccum leak or o2 sensor.The car is running great so I have been doing other fixes first.I drove the car yesterday durring some monsoon like wind and rain for 3 hours.When I parked the car last night CEL was still on.When I drove the car to work this morning the CEL was off and has stayed off all day about 50 miles of driving.I plugged in a code reader when I got home and there are not any codes being shown at this time.In the past week or so I have replaced the alternator,serp belt,brakes,tires,oil change (castrol full syn),air filter,cabin filter,and fuel filter.None of these have anything to do with the code I had been getting.Should I count my blessings on the cel or should I investigate furthor to make sure everything is alright.These things dont just go away or can they?
thanx
Ben weekes

vlvman · Post by **vlvman** » 04 Apr 2009, 18:54

Some codes can clear themselves after 3 drive cycles without the problem appearing. O2 codes are often the result of exhaust leaks. If your code is an O2 code you should carefully torque the exhaust manifold bolts after soaking them with PB Blaster for 3 days. Also check for other exhaust leaks. You should not use RTV silicone on any intake or exhaust gaskets as silicone will affect O2 sensor readings, and can ruin an O2 sensor.

Post by **MadeInJapan** » 04 Apr 2009, 20:35

I suspect some slight vacuum or exhaust leaks that sealed themselves with some warmer weather or from blowing fumes through the exhaust which has, after awhile clogged up the leaks that were there to an extent that the O2's are happy again.

Post by **benweekes** » 06 Apr 2009, 10:05

UPDATE
Well I counted my blessings and they ran out today.While driving to work this morning the dreaded CEL came back on.I have visually looked for any vaccum leaks and not seen anything that says here I am.Is there any other way to test for vaccum leaks other than going to a shop for a smoke test any home versions?I think there might be a small hole in the exhaust equal in distance to the front doors havent seen anything yet but sounds like there might be a small one.Could this be the culprit?Thanx again for any help

Ben Weekes

Post by **MadeInJapan** » 06 Apr 2009, 16:04

At idle spray some carb cleaner around the small hoses and intake manifold...if you have a leak you'll hear your engine surge (and you'll find your leaks).

Post by **benweekes** » 06 Apr 2009, 19:07

I'll give it a try and let you know what I find thanx again MIJ for the help.
Ben Weekes