sk8ray

Hello,

I have 2006 Scion xB with 59,800 miles on it. I've babied this car since I first got it, brand new from the show room. To the point:

Intermittently, the 3 lights, (VSC, Trac Off, CEL) came on. First time was when I was idling (cold weather and had heater on) outside the grocery store while my partner went inside to shop, for approx 15-20 min, those 3 lights came on and I felt the engine, like it was losing power/RPM. I tapped the gas pedal to feed more gas to the engine, felt the stumble, turned the engine off and had a look at it. Started it up again and drove it home slowly, with the lights on, thinking about taking it to the dealer the next day. I totally forgot all about it and a couple days later had to go to meeting a few miles out, no lights or engine stumble. A week later, doing errands, and parked/idling for few minutes, the 3 lights came on again. Drove home slowly, bought and scanned for the code, I got the P0302, which indicates that cylinder #2 is misfiring. So I replaced all 4 spark plugs and looked at the coil packs closely, even swapped them to see if the #2 is faulty, to no avail. Next morning, started it up and it drove just fine for a bit on a short errands. Fast forward to today, I drove for about 60 miles and stopped a grocery store to get something to eat, and I wanted to test the engine, idling for few minutes, the 3 lights came on again and the engine start to stumble. So that makes me think it has something to do with the temperature around one of the sensors while the engine is hot. Can anyone think of something on this or point to possible sensors? Your help is appreciated.

Ray

go_part

This sounds like an ecu related problem due to the fact that this issue causes the VSC and Trac Off lights to come on. The crankshaft and camshaft position sensors don't usually do things like that when they fail. They can however be the cause for a misfire/no start condition.

tricha19

So you did move ignition coils? No change in codes?

Given that your CEL/symptoms always happen at idle, I'd suspect that you have a vacuum leak on that cylinder, possibly around the intake. If you can view freeze frame data with your scanner, post the data.

The face that your VSC and traction lights come on is typical of Toyota products, and does not necessarily indicate a problem with those systems.

Fix your misfire first and I'll bet the other lights will stay out.

AnalogXB

Hi Ray, I had this Issue on so many levels once upon a time. LOL!
I even made a thread about it a few years ago here: https://www.scionlife.com/forums/scion-xa-xb-1st-gen-drivetrain-power-1638/vsc-trac-off-check-engine-light-came-81815/

But I'd like you to try this: there is an EFI fuse in the fusebox under the hood. , remove that and leave it out for say a minute or so. This will Reset the ECU's settings and post back to its original factory defaults.
To my understanding the early XB's from 2003~2004 had ECU's that were "fixed" in settings, minor things were "auto learned". The 2005~2007 1st gens had an Auto Learn ECU, which basically learned driving habits as you go along. The idea for this was for the ECU to find the optimal Air/Fuel ratio's, valve timings and all that stuff. The downfall was every now and then, as perfect as this system has to be at all times, the ECU makes a slight miscalculation and something is slightly off causing to throw those lights on. Resetting the ECU would then reset all parameters and set all engine components back to its original state. It would then re-learn your driving habits and so forth.
As others said, you might have issues in temperature, or maybe an engine coil/plug was temporarily buggy throwing error codes. Maybe something was in the #2 cylinder chamber like excess carbon deposits causing horrible firing and so on. But at least the first thing to try is resetting the ECU, now if you dont want to pull the EFI fuse, you can always take off the battery terminal. Its entirely Up to you, the only thing is taking off the battery terminal will erase your clock and radio settings.
This is at least a start to see if the code will stick around or not, if it does happen to come back, then there is indeed a problem in the #2 cylinder as you referred to.
The most common problem with those three lights, were the Camshaft Actuator and Cam Gear Position sensor. Was a pain !!!! the solution to this was I aquired a revised camgear which came out mid 2007 and I had a revised ECU which also came out in mid 2007. I even had the Cam actuator replaced, no lights ever since.