I have a 1997 camaro z28 totally stock besides a loud mouth catback. I noticed the service engine light on so I had autozone put a scanner on it and they came up with P0141 which is the o2 sensor for bank 1 sensor 2. I purchased the sensor hoping that it would fix the problem for $80 and had a mechanic put it in for $20 because I'm in college and don't want to change it in a parking lot. I know that sensor 2 means that it is behind the cat. I also know my car has a y-pipe but do I have 3 o2 sensors or 4? I should have looked but dont want to lay in the snow in the parking lot. The light was off for one day then came back on so I took the sensor to autozone and got a replacement just to make sure that wasn't the problem. The light came back on in another day. I run premium fuel and added some fuel system cleaner. I don't know if it could be a bad plug, injector, etc... Any advice would be much appreciated.

 

P0141 = B1S2 heated O2 sensor HEATER CIRCUIT.

Has nothing to do with the O2 sensing element, using premium fuel, or fuel system cleaner, a bad plug or a bad injector - its an electrical fault.

Let's start by moving this to the "LT1 Based Engine Tech" forum, since this is not an Advanced Tech topic.

96 and 97 are dual cat cars. On each "bank" of the engine (B1 = drivers side; B2 = passenger side) there is a pre-cat O2 sensor (S1), a catalytic converter and an after-cat sensor (S2). Total of 4 O2 sensors. Each sensor is "heated", meaning it has a 12V circuit to help the sensor reach operating temperature faster, and keep it at that temperature.

The 2 pre-cat sensors control the A/F ratio for the respective bank of the engine. The 2 after-car sensors are only there to check and make sure the cat is working. P0141 means the after-cat O2 sensor has a faulty reading on the heater circuit. The circuit can be bad because of the fuse, the wiring to the sensor, or the heating element in the sensor can be faulty. The PCM diagnostic measures the time required from a cold start for the sensor to reach operating temperature, an sets the code if it takes too long.

Its not likely to be a problem with the fuse, since the same fuse powers the heating element in all 4 sensors, but you should check the fuse, in the underhood electrical box.

If the fuse is good, its either a wiring problem or an O2 sensor problem. The cheap way to test (before spending money on a sensor) is to swap the Bank 1 and Bank 2 after cat sensors with each other. If the problem stays on the driver's side (B1S2), it is a wiring problem. If the problem follows the O2 sensor to the passenger side (B2S2) it is a sensor problem.

You need to check the fuse, and the wiring, since replacing the sensor did not fix the problem.

 

Is someone clearing the code for you each time the sensor is replaced? Just wondering, since the only way for the light to go off is to clear the code or for the PCM make ~3 runs with the issue resolved.

 

Thanks guys, I appreciate the help. I checked the fuse and it is fine. As soon as I find time I will switch the sensors and see if it is a bad sensor or a wiring problem. I will keep you up to date. And the guy that changed the sensor cleared the code for me.

 

Hey guys, the guy I had put the o2 sensor in put it on the passenger side instead of the drivers side. So it was just a bad o2 sensor like I thought, but he put it in on the wrong side. Thanks for all of your help! The car is running like a beast!