Pint07

My CEL came on and gave codes for both of the front O2 sensors. I replaced both of them yesterday, reset the light, and drove around without having the light come on. The next time I start my car, the CEL returns and gives code 7-7, for the rear heated O2 Sensor. However, I was told on these boards that you never really have to replace the rear O2 sensor, because when the front O2 sensors are behaving normally, the rear will not throw codes.

Does anyone have any ideas on what I could do to get this code off without replacing the rear O2 sensor?

99BlackMaxMS

iTrader: (85)

I'd just pony up and replace it, you'll spend more money/time/effort wiring up an O2 simulator than you would just replacing the part.

Pint07

But idk. I was thinking, would it just take time for the system to recognize the new sensors? The front two should be behaving normally which would mean once my system realizes that it should stop throwing codes for the rear, correct?

Kevlo911

iTrader: (36)

You can replace it if you want, or you can get a simulator. In my case, taking out the o2, the sensor stripped all the threads on my exhaust so i just put a simulator instead

Kevlo911

iTrader: (36)

The rear o2 monitors the cat, it has nothing to do with the front sensors

oldngivout

iTrader: (8)

There's a chance, that maybe, just maybe, that the code being generated by the ECU for the rear oxygen sensor could in fact be valid. Why don't you replace it and see? It is a common issue with our cars. Whoever said this:

-that you never really have to replace the rear O2 sensor, because when the front O2 sensors are behaving normally, the rear will not throw codes-

doesn't know what they are talking about.

99zx2

iTrader: (3)

had a 0707 on our car too, got a new rear 02, and no light so far

ImmaSquashYou

iTrader: (7)

if the 02 sensor is your only problem, consider yourself lucky. Just order online and don't buy it at a store. But to your question, no that is not true. Otherwise, why have the sensor there in the first place if it doesn't do anything?

asand1

iTrader: (1)

After cat sensor monitors cat efficiency. I believe it relys on the front sensors for a good "before" reading to compare, but that would likey result in a catalyst effeciency code rather than O2 code.
A bad secondary O2 will ALWAYS throw a code, but it will NEVER affect performance or mileage. Change it if you dont like the light, or need to pass inspection. Otherwise ignore it.

BenL

I just have the rear O2 sensor on mine zip-tied to its own insulated wires under my '96 to keep my CEL off, because I would like to know when I have REAL problems with sensors or my car.
To explain exactly why I did this to my Max: a friend of mine was driving my Max one day a while back (won't be happening again, I can assure you of that), the exhaust pipe from the flex pipe back rusted through and broke off, he cut the wires because it was too hard for him to simply unplug the O2 from under the car -- I crimped the wires back together and said screw the cat when I finally managed to get the money together to put an exhaust on it (myself, of course).

Jneilan28

Is the Front Right Heated O2 sensor before the cat? this is my first problem with an o2 sensor and i dont know much about them.

99zx2

iTrader: (3)

yes, two before the cat and one after.