i have a 2008 chevy suburban. check engine light cam on had checked was told o2 sensors needed to be replaced. did that approx 40 miles later light back on. back to shop told 1 replaced sensor was defective so was replaced. 40 miles later light back on - told low voltage so replaced battery - all was good for about 200 miles and guess what yep light back on. code reading everytime p1133. failed emmissions inspection - any suggestions - this thing is driving me crazy. took it to 3 different shops and got same p1133 reading every time. told by all 3 shops they didn't know what to do to fix it at this point.

Before all the "brand issues" comes up, if you're only changing the front one, I'd recommend changing the rear sensor with the exact same brand. I just went through this and running dual Bosch sensors cleared my same code. Two different brand units, especially when one is older, seems to bring out the differences in tolerances when the computer takes it readings. I know it reads Bank 1 but there is history with GM recommending changing Bank 2 also on some other forums and the issues went away like mine did. I just refused to pay a premium for a Chinese made AC Delco rebox item when the Bosch runs fine. I've heard some folks say they had issues with Denso units but that is heresay and I've never run them.

suburban likely has four and i would wonder if they all were replaced and with decent quality ones. as he said there are alot of cheap ones and you really get what you pay for with o2 sensors. and i wonder if one of the wires isnt loose in the plug or something is wrong with the heater circuit

Yeppers, some of the listings show 4 but not sure of the engine so that could get expensive. I'm thinking the computer still has to do both sensors against each other and I suppose they have to match the two sides then? Damn, what a mess and you're right about the wiring so now there'* 4 sets of 4 wires to worry about. Thanks goodness I only have 2 sensors....

my yukon has four, the two up stream ones control fueling and the down stream ones just monitor the cats. I had lights on when i got mine but they are cheap, like 25 bucks at rock auto or amazon for bosch

a few years back I was having idle and start problems and got a code for a failed oxegen sensor. I had the sensor replaced but didnt help. Later found out the problem was fuel pressure regulator. It was flooding the the engine at idle and fouling up the sensor. Replaced regulator and no problem since.

If your truck is a 4WD check the wiring harness the runs near the front drive shaft at the transfer case. The harness will hang down and rub the drive shaft.

Also I want to note that just because 1 O2 is faulty does not require you to replace any others. If you use GM parts and the fault has been diagnosed CORRECTLY there is no need to replace other sensors.

You are are the point where, you need a scan tool to read, the bank 1 pre cat O2 sensor data....while watching the data, you manually create rich/lean conditions to see if the O2 sensor responds...if it does, then the sensor is not the problem.....if it doesn't, chances are it'* something like a harness/VCM problem...

there are a ton of codes referencing o2, lean rich, heater(h-circuit)etc.... this one is the not enough switching is supposed to tell you when the o2'* need replaced and if one goes the other is not going to be far behind, not matching them would be like waiting for each individual spark plug to fail.

If that was the final say and you were CORRECT in your assumption, why has GM continued to pass along the need to try changing the other sensors also? A quick look at numerous forums on this very issue shows they recommend this course of action a lot when involved with service departments having no luck fixing the issues and vehicles continue to throw the code. High mileage sensors are like any other parts, they lose their tolerances and performance levels and do not always to continue to meet factory specs. Using a new and old sensor together DOES in fact still leave the door open for the computer to flag these variances as an issue. It isn't a case of every other tech being less capable of diagnosing such issues.

And for your information, since you feel the need to shoot down anything you disagree with, GM does not make sensors and neither does AC Delco. They're reboxing Chinese sweat shop parts as most companies now do. Case in point, Delphi Controls is now working out of a crap hole in China slapping trogether sensors and control devices since the US workers were canned to increase corporate profit. To claim the use of a supposed GM made part is a superior repair procedure is ludicrous and uninformed to say the very least.