2 questions about my '05 xB

Hi there,

I have 2 questions for you great folks about my 2005 xB, 137k miles. Please keep in mind that I know very little about cars - I can change a tire (yes, I’m a humanities professor).

  1. It’s been setting a code combination of VSC, Trac OFF and Check Engine. All three come on at once. I had the guys at pep boys check the codes and the only code that was being flagged was a “very small leak in the Evaporative Emissions System” What does this mean? Someone told me that the first thing I should do is replace the gas cap. Is this true?

  2. I noticed that there’s been some chugging over the past few days when driving. At about 3000 RPM, the car hesitates as it’s cruising down the road. I was having this problem in May during a long trip and some fuel injector cleaner did the trick. Could I already need to add more? The car has a new battery and I will be replacing the serpentine belt next week.

Thank you for your kind assistance.

That check engine light on likely turns the other systems off so that’s why those lights may be on. The check engine light is the first concern.

Depending on the code the guy at pepboys read, it could be something as simple as a bad gas cap. Do you know the code? It will likely look like PXXXX, where XXXX is a number.
If the gas cap is cheap, replace it and see if it goes away.They can cause codes to be thrown.

Regarding 2, it really could be anything. You could run some Techron fuel additive through it as that is a cheap thing to try. Sometimes it does the trick but it is not a catch-all solution. It could be related to, for instance, fuel delivery or a misfire. It would be impossible to tell from here.
The check engine light could very well be trying to tell you what the problem is - again, it depends on what code was read.

The check engine light could be as simple as a loose gas cap. First, make sure your gas cap is tight. If it is, then try a new gas cap. If that doesn’t work, a mechanic will have to track down the leak in the evaporative emissions system.

The VSC, Trac Off warning is unrelated and maybe due to a bad wheel speed sensor. It’s not terribly important, but it does mean your stability/traction control system is temporarily disabled. Your dealer or a comoetenet mechanic should be able to diagnose. Usually it involves replacing a faulty sensor.

The chugging is difficult to diagnose. You could try more injector cleaner, but the improvement you experienced might have been coincidental. It could either be a fuel problem (injectors, fuel pump, etc) or an ignition problem (coils, plugs, etc).

Note sure about Xions but on some cars the check engine light trips a bunch of other lights as well. Maybe they want you to take notice or maybe the check engine light affects the other systems’ performance.

@FilmProf, do you stop filling when the pump stops or do you fill to the nearest dollar?
If the latter, don’t do that any more. That screws up the evaporative systems of cars.

Thanks for all of the suggestions.

@RemcoW I usually just fill it up until the pump stops. When you mean “fill to the nearest dollar,” do you mean “topping it off?” I usually don’t do that, but have once in a while…

Yeah, don’t do that - ever. It really messes your evap system up and is pretty costly to repair, especially considering it could have been prevented.

Ok. I didn’t see the actual code number on the tool that the Pepboy guy had. I just read the code description. The gas cap is $24 from the dealer. Are knockoff parts just as good or should I buy official?

I picked up a bottle of Lucas injector cleaner so I’ll put it in and repost back and let you know if it worked. It’s due for a tuneup which I’ll be doing next month.

I like original parts because sometime aftermarket parts are crapshoots. Sometimes they are made by the same company and function well, other times not.

I’d go with the dealer’s part, too.

$24 isn’t much to spend, Doc, even on an academic paycheck. Keep responding. Another humanities professor will show up soon and you guys can have a good time. He’s even a motorhead. @Triedaq, where are you?

At 137,000 miles, there could be several things wrong. Work on one a time as long as drivability isn’t badly affected. The CEL won’t turn off as soon as you change the gas cap if that is the solution unless you disconnect the battery for 5 minutes.

Replacing the gas cap is worth a try, but use an OEM cap, which means it is the same specs as the one that came w/the car new, probably you have to buy it from a dealership. If you don’t do this, you may save some $$, but you risk replacing the cap with one that is worse than the one you already have. And even with an OEM cap, replacing it may not fix the problem. It could be an evap purge valve or something else that is leaking. No gas fumes are supposed to escape to the atmosphere, it’s a federal pollution requirement, and that code is saying they may be, but from where remains a mystery. It is like if someone said a mouse got into your house, because they found a mouse inside. But how it got in? More inspection is required. You might find a hole and block it off, but it doesn’t mean there isn’t another hole too, and the 2nd hole is how the mouse actually got in. So you need a mechanic to find out why your evap is leaking, and where.

Anyway, if a new cap doesn’t fix it, find a shop which has the manufacturer’s scan tool for this car. Since you have the evap problem and a drivability problem, that’s a double whammy. You need a shop that has all the correct tools. Otherwise you’ll have to resort to a hit and miss parts swap procedure. Ask the shop if they have the ability to measure “fuel trim” on your engine, that’s a clue they’ll know how to diagnose this kind of problem.

The VSC problem as mentioned above is likely a faulty wheel speed sensor, a common problem. Might as well get that taken care of at the same time, as the same scan tool can be used to diagnose that too. Could be something more serious too.

Given that you have 137 K and multiple problems, if this were my car, probably the first thing I"d do is bring all the routine maintenance suggested in the owner’s manual up to date too. Will save you time, money, and aggravation in the long run. Often the process of doing all that will discover other problems, some of which may be the ultimate causes of your symptoms. Best of luck.

$24 isn’t much to spend, Doc, even on an academic paycheck. Keep responding. Another humanities professor will show up soon and you guys can have a good time. He’s even a motorhead. @Triedaq, where are you? -
@jtsanders–actually I was a math and computer science professor, but I have been retired for two years.
At any rate, I think the best thing for a person in academics to do is to keep an old car running. I bought a new Oldsmobile Cutlass Salon in 1978 and drove it until I retired in 2011. It did get me reliably back and forth to campus. More important, it was a good car to drive to social functions held by the administration. I reasoned that it was best to attend these functions looking poor.
At any rate, I do have a good independent shop. I did have to learn all the hiding places in the shop’s building, but once I found a technician they did a good job in keeping the car going at a reasonable price. It was much cheaper than buying a new or newer car.

Anytime the Check Engine light comes on along with the VSC and Trac OFF light warning lights it means the VSC and Trac system won’t operate with the Check Engine light on.

The computers in these three systems communicate with each other. So if there’s a problem with the engine management system, the other systems will automatically shut themselves off and not function. So those lights come on to warn you of this.

The same thing holds true with ABS. If the primary brake warning light comes on the ABS light automatically comes on. Because the ABS is warning you that it’s not going to function until it’s found out what’s causing the primary brake warning light to come on and it’s repaired.

Once it’s found out why the Check Engine Light is on and it’s repaired the other lights should shut off.


I also have a 2005 Scion xB and the same thing is happening to mine. I took it to the dealer, who charged me $70 to clear the sensor and told me that it was possible I had a bad sensor. He told me that if it happened again to bring it back in and they would change the sensor for $600. I was pretty far away from the dealer when it happened again so I took it to a local garage. They cleared the sensor and told me there was nothing wrong with the car just to keep driving it. Incidentally they didn’t charge me anything for this service. When it happened again, I took it to another garage and was told the same thing, no charge. Since then I have noticed it comes on and stays on until it is started for 5 or 6 times then goes off and stays off for quite some time. Runs fine and gets great gas mileage. I am technologically challenged so I do the best I can. I have questioned other people about the service stations and have only good things about them. The dealership is known for high prices and I just don’t trust them.

My 2005 Xb experienced a similar issue around 115k. An additional symptom was difficulty in filling the gas tank, where only a very slow feed was accepted. This became more and more intrusive until it took 8 to 10 minutes to fill the tank. You should expect this symptom to show up when winter becomes severe. The solution was a failed venting system in the gas tank, requiring a $140 part and $200 of labor. Check engine light is off, and I have ABS and MagicTrak back on. Your experience may vary. Good luck.

I’ll try the OEM gas cap for the codes. As for the chugging, I assumed it could’ve been bad gas so I threw in some more and Lucas fuel injector cleaner. It’s still doing a chugging at low speeds (below 50) and at a stop light. Sometimes the idle RPM will dip down to 800 at which it’ll chug and spurt and then go back to 1000 RPM.
It’s intermittent as well. Sometimes it’ll chug/hesitate/rough idle and then it will ride smoothly.

@jtsanders that’s quite funny. true, not all humanities professors fall into Tom and Ray’s “mechanically inept” stereotype, but I do, I’m afraid.

@goldenduck I also have a slow feed into my gas tank however that is mainly caused by a plastic part from a gas can that I got stuck in there a few years ago. Refueling is now a chore - I’m able to eat a 6 course meal in the time it takes me to get gas. Like I said, I’m technically challenged with cars and just shoved the whole nozzle from the gas can in to the fuel tank - oops.

@dolls65109 which sensor? is this something i can clean myself?

As for the chugging, intermittent problems like that can be hard to diagnose. But I’d start by checking the ignition system (spark plugs, plug wires, ignition coil, distributor cap and rotor) and replacing any of those that are old/ worn. Basically a tune-up, which you may be due for anyway.


I agree that a tune up is a good idea

But OP’s car has coil on plugs

I’m still stuck in the Stone Age of ignition coils. :wink: