CK9887

iTrader: (1)

A few weeks ago, my check engine light came on along with the check VSC. I continued to drive the car and after several start cycles and roughly 40-50 miles, the lights went off and everything was back to normal.

The same problem happened just last week and again, after my daily routine and errands, the lights went off again.

Today, the lights came on again. So this is the third time now this has happened.

I have searched on this forum and found a bit of information of other members having similar problems. From what I've read, it sounds like it's either a bad 02, MAF or faulty gas cap. I did notice my gas cap seems like it's not clicking like it used to. It seems to screw on securely but it doesn't have that firm click. Maybe this is the problem?

So have any of you guys had this problem where it was intermittent like it has been with my car? Car seems to fix it self after several drive cycles but then the lights will kick back on a week later.

The car is an 08 IS-F. Car has Takeda intake and straight pipes after the cats and 02's. I don't think the intake or exhaust would be the root of the problem because I had put several thousand miles on the car with these mods with no problems.

Any suggestions?

itsmike177

iTrader: (3)

Had this happen on an 06 IS350, 100% stock. "Check VSC" and a lot of other warning lights in the IP would sporadically go off and on, sometimes hundreds of miles in between. Did not affect driveability, but worrisome when it's being displayed.

Dealer diagnosed it to a faulty "brake light switch" and replaced it under warranty.

zapa

well the codes would be helpful

MicaISF

have the code scanned. meineke may do it for free. dealer will probably give you crap if you have exhaust and intake.

digger08

iTrader: (1)

With the frequency they come on, (if I was to speculate...without check engine light codes)

P0420 - is usually the culprit after exhaust and intake work. It won't kill you to check the following areas, that you are ruling out.

Check that O2 sensors were not mangled or damaged by the exhaust installer, from not having the proper tool - if damaged these usually come on like clockwork and will not go away after a few drive cycles.

There is a pin hole leak in the exhaust upstream, probably at the exhaust connection point to your straight pipes. This will cause the lights to come on randomly, but usually when you punch it on the hwy. There is flex in the exhaust underload and if the connection is not tight or you reused a gasket - it will trip lights like your getting. Get new gaskets!

Air leak at the air filter box, sucking in to much air. - Check the connection points for all of this work you did with the Takeda

This is all speculation of course, and even after you get a code read, it can still point to 12 things not just the exact problem. What it will tell you is the area of concern.

Digger08

CK9887

iTrader: (1)

So the lights had been on for the past few days and they just went off again tonight. I was going to have the codes checked but now that it's not throwing a code, I guess thats not an option.

Due to the fact that the problem has been correcting itself, I don't think it would be an 02. The 02's don't start to go bad, they either are good or they are not from what I understand. Probably same with the MAF....

I have checked the MAF plug on the Takeda intake and everything seemed ok but I will re check.

Next time the light is on I guess I'll see if I can get to Lexus.

digger08

iTrader: (1)

Exhaust leak on the mid pipe, is turned on by your O2. Do not dismiss this or confuse this as a bad o2 sensor.

Digger08

CK9887

iTrader: (1)

If it was an exhaust leak, why would the problem correct itself? An exhaust leak is going to be a continual problem

digger08

iTrader: (1)

Because the exhaust seal opens up under load or pressure, turns on the CEL, then closes back up...the car goes through its 3 drive cycles sees no more problems and turns itself off. Even a pin hole leak will cause the same cycles as it is completely at random.

This is all speculation until you do the correct diagnosis. I simply gave you some common reasoning.

This seems to be the logical one, as you continue to trip a code, that seems to reset itself.

.....you could also go to a parts store and buy your own pocket code reader...its not like you will have a one time use


Digger08

iH8RICERZ

iTrader: (4)

Mine just came on this morning as I pulled out of the driveway. It also did this last week right before I was about to get on the freeway. I just shut off the car and restarted it and it went away... based off of what digger08 wrote, I'm probably thinking my borla exhaust is to blame for this. Going to crawl underneath the car hopefully this weekend to see if anything looks abnormal.

Joe Z

iTrader: (10)

Agree with digger08...

The crush gasket leak would be located at the manifold & front pipe connections.

Sometimes you'll need "new" gaskets to solve the problem..

Toyota Part # 90917-06078

~ Joe Z

CK9887

iTrader: (1)

Lights have since come off and gone off twice more since last posting. Lights are currently on and will be taking the car to Lexus tomorrow. I've established a decent relationship with my local service rep and with the car still being under powertrain warranty, I'm almost certain they will at least diagnose the problem for free.

I'll update after tomorrow when Lexus gives me the verdict.