O2 sensor problem

I have a 1998 Pontiac Bonneville with the 3.8L V6, not supercharged. The check engine light is on. Autozone read the code as P0141, but they are unable to tell me which O2 sensor is bad, before or after the cat, or how many sensors the car even has. The car has 114k miles on it. I am not against replacing all the O2 sensors, but I need to know how many to buy and look for. Any help on this would be appreciated.

I believe that code is for the heater circuit in one of the O2 sensors after the converter. Before buying any O2s you should check all fuses as the O2 heater circuits are supplied from a fused, protected circuit.

Keep in mind that O2 codes do not always mean the O2(s) are at fault, no matter what the code is.

Bonney Man, Did They Turn Off The Check Engine Light On Your Bonney Buggy ? Usually It Will come Back On In A Short Time, But sometimes It’s Just A Fluke. Been There, Done That.

If you are going to do your own car repairs and don’t have one, buy yourself a code reader and you can retrieve codes and turn off the light. It’s a must have.

I think you can buy an Actron Pocket Scan at Advance Auto this month for less than the 50 bucks Sears gets for them. I think they have 50% off on them. Check it out.

Proud Fellow Bonnevile Owner / Operator

I looked in the owners manual for a fuse for the O2 sensors and I couldn’t find one listed. The closest I got was labeled “Miscellaneous engine controls (OBDII)”. That fuse checks out OK.
As far as I know Autozone did not turn off the check engine light. I’m pretty sure he just read the code and gave me the printout. I have been thinking about getting some type of code reader. Caddyman posted the following link a short time ago:


Looks like something my son could get excited about. He is into electronics and built a cable to read the data from my '88 Suburban while hooked up to a laptop. Was cool and fun to play with. So I’m thinking of ordering one of these.
But I still have to get this car fixed. On the printout from Autozone, it said possible causes were bad fuse, bad connection in the wire or bad sensor. I’ll crawl under there this weekend to check the connection, but I think without a service manual, I am up the creek. I don’t know whether to throw a couple new sensors at it or take it to the mechanic and let him fix it.