help - Hey guys, It's been a while since I've visited you guys, but today I return for some advice. Today, I went and had my brakes inspected by a ...

Hey guys,

It's been a while since I've visited you guys, but today I return for some advice.

Today, I went and had my brakes inspected by a local shop that does the fleet service for the company I work at. While there, I suggested a brake fluid flush. They looked at it, and said that it could use flushing. I went ahead and had them do it. All was good, until I started driving home. I soon noticed on the dash "service brakes soon". I didn't think too much of it until I got home and saw it yet again. This time there was a check engine light on too. I called the shop up and asked, "what gives?" He didn't really have a good answer on what could be happening, so he said to just bring it in this coming Monday. I told him that the brakes are fine and that I wasn't too worried about it. I also said that I would check the code when I got home. I checked the code and it showed up with three codes completely unrelated to the brakes:

p0171 system too lean (bank 1)
p0174 system too lean (bank 2)
p2271 sensor signal stuck rich - bank 1, sensor 1

It confused the crap out of me. What are the chances that two unrelated problems would come up at the exact same time? Yet, I have no idea how they could be related... maybe they accidently knocked something when they were bleeding the brakes? I'm not sure what to think. For now, I reset the codes to see if they come back on.

That being said, what do you guys think? What do you make of the codes? Possible a faulty 02 sensor or something like that? Any advice would be greatly appreciated, as I am quite worried. My worry may be unwarranted, but knowing something may be wrong with my baby is sickening. Thanks for any help, and it's nice to be back on the forums.

-Blake

It does sound like they may have knocked a vacuum line loose and is causing the lean condition. I'd have to have more information as far as why the service brake light is on.

Possibly. I hope so actually, as that seems fairly simple to fix. How would I look for it? As far as the brakes go, what other info do you want to know? haha

I assume there are brake codes that your code reader can not access. I'd like to know what brake codes are present. You can try spraying brake or carb cleaner around your intake and see if the idle speed changes. If so, you need to look for the leak near where the spray was when the speed changed.

I don't have any available. I think I will just bring it in to them next week and mention what you said. Thanks for your help. Kind of puts me at ease for now. The brakes feel fine btw, and the fluid is full.

Be sure to let us know what it turns out to be.

Will do!

After emailing the people who worked on the truck, he did some research and figured out what must be wrong. He, of course, plans on covering everything to get it fixed. This is what he said:

"I talked to the technician that worked on your truck after you called earlier today.
He said he saw some fluid on the back of the brake master cylinder when he did the
brake fluid flush so he pulled the master off the brake booster to see if the rear
seal on the master was leaking. He did not find a leak, so he re-mounted the master
to the booster. I have done some research tonight and found there a is a TSB
(technical service bulletin) from GM on this. The TSB states that if the master is
removed from the booster the seal between the two parts can be sucked into the
booster (the booster holds vacuum) and cause the check engine light to come on and
cause two of the codes you pulled. The TSB # is 08-06-04-016, you can google it and
read it for yourself. My data program won't let me cut and paste it otherwise I
would. My technician was trying to do the right thing and make sure there was not a
problem, but his actions inadvertently caused a problem. We need to get the truck back and
check it out. Please let me know when you would like to bring it in."

I'll let you know how everything works out.

thats good to know

I'd definatly use those guys again. They owned up to their mistake and are standing behind their work. The technician also did an above avearge job by making sure you did not have a leak with the master cylinder. He made a mistake, but it was an honest one.