: Oxygen sensor problems

08-15-04, 01:38 PM
I got an error code and looked it up on the internet, according to the internet, the oxygen sensor is not functioning normally. I want to replace it, but i don't know where to get one, where the sensor is located, and how to replace it. please help me!!!!! :worship:

08-15-04, 01:58 PM
Tell us what the code is and we can tell you which of them needs replacement. There are 4 O2 sensors. One on the exhaust manifold for the front bank of cylinders, one on the rear bank, one just in front of the catalytic converter, and one behind it. The code will tell us exactly which one needs replacement. If this is the first time the car has ever shown a code for an O2 sensor, it is most likely the one before the catalytic converter. I own the service manuals and can tell you which one it is.

As for where to get them, the auto parts stores in the Chicago area carry at least the Bosch brand, and some carry the OEM sensors. I and everyone I know have always used the Bosch sensors and have had very good luck with them. I have heard people say to use the OEM sensors, but I can't tell any difference other than the OEM sensors are substantially more expensive. Tell the parts store what year and model Cadillac you have and they'll present you with probably two options. The sensors on the manifold for each bank are one type of sensor, and the two before and after the catalytic converter are another type. They're sold as "front" and "rear" sensors. The front ones are for the individual manifolds and the rear ones are the ones around the cat.

So get those codes! You can look them up yourself here:


Or just post them and someone will be able to tell you exactly what to do. Expect to pay around $60-$90 for a Bosch sensor and $80-$120 for an OEM.

Michael Cowden

08-15-04, 02:17 PM
the code is pc0133, according to the link above, it is bank 1 sensor 1, where is that sensor located?

08-15-04, 03:33 PM
OK, that's better... Bank 1 sensor 1 is the sensor in the exhaust manifold for the rear bank of cylinders. I was able to successfully change that sensor on my 96 SLS from the top side of the engine compartment with a long 1/2" extension, but it may be more easily accessible from the bottom on your DeVille.

You can get the sensors at most major auto parts stores. In the Chicago area, I've found them at Pep Boys, AutoZone, and CarQuest. They may ask if you need a "front" or a "rear" sensor. The front sensors are the ones on either side of the engine, and that's what you need in this case. The rear ones are the ones on either side of the catalytic converter. If you get it home and the wiring harness doesn't match, don't go cutting things up to make it work. Go back and get the other sensor.

You will also need an oxygen sensor socket to remove and install it. It's basically just a socket of the correct size with a notch through it for the wires. You can borrow the socket from some auto parts stores for a small deposit. AutoZone wanted a $15 deposit, Pep Boys wanted $25. You can also buy a socket for around $15-$50.

Disconnect the harness from the sensor and remove it from the manifold. Use steady, even pressure to remove and install the sensors. Pounding on the ratchet with a hammer could damage the sensor or the threads in the manifold. The new sensor will come with a plastic cap on it and some anti-seize compound on the threads. Don't get the anti-seize, or anything else, on the sensor head or it could be damaged. If there is no anti-seize on the threads, you should buy a small tube and use it so you can get the sensor back out if you need to in the future.

Avoid the "universal" sensors. With those, you have to splice the wiring harness from the new sensor with the harness from the old sensor, and those splices can be a point of failure.

Hope that gets you where you need to go... Let us know how it works out. Good luck!

Michael Cowden

08-16-04, 02:36 PM
Hi I am trying to replace a O2 sensor in a 1996 Sedan Deville. The Snap On scanner is giving a "Lazy O2 Sensor - Bank 1 Sensor #2" message. The local dealership is telling me that there is only one O2 sensor in this car. The local parts store has 3 options for replacement O2 sensors including upstream and downstream sensors. Any ideas? Thanks in advance. Jim

08-17-04, 03:43 AM
Local dealer says 'one'.....hmmmm. There are 4. Bank 1 sensor 2.... is the one mounted just ahead of the catcon. No question.

Logan Diagnostic

08-17-04, 09:07 AM
Thank you.