Is it common for all Oxygen sensors to fail at the same time?

I have a 1998 Ford Ranger with 130,000 miles. I don’t believe the Oxygen sensors have ever been replaced. I just went for inspection, and the “check engine” light had been on for nearly a year, but the truck ran fine. When they ran the codes, the mechanic said that he had to replace all three Oxygen sensors, which cost me just under $400 (parts and labor). My questions are:
A. Is it unusual for all three sensors to be bad at once?
B. Is the price to replace the three sensors high or average or what?

Appreciate the help!!


When one fails, the others are usually weak and not far behind. Since these sensors work together as a team, it’s important they all match each other…$400 to replace 3 of them sounds like a fair price…Three is an unusual number to have…It’s usually 2 or 4…If your truck is a V6 you may have one for each bank and one behind the converter…Do you remember the exact code that was pulled from your trucks computer that led to the oxygen sensor diagnosis?

It is a V-6, 3.0 liter. I have no idea as to the code. You have at least helped to take the sting out of the whole thing. I have always used this mechanic for the last 12 years, and it’s good to know that he was not gouging me. Thanks so much for your reply.

I expect the shop’s experience is that if one fails, it is usually cheaper in the long run to just replace all of them. They’ve probably tried to just replace one, and the customer routinely returns with another problem, requiring the next one to be replaced, etc etc. $400 seems very reasonable for this to me.

Going forward, to keep your O2 sensors in best condition possible, don’t add weird fuel additives, and make sure to keep the routine maintenance suggested in the owner’s manual up to date, and esp if the check engine light comes on, get that fixed asap. Best of luck.

So, now the big question: Is it reasonable to assume that these three new ones will last at least for 50 or 60,000 miles (the rest of my life, probably)? Or can I expect perhaps another 100K?

If all of the O2s were actually faulty and all failed at the same time this would generally mean that something killed them. Engine coolant into the combustion chambers, excessively rich running or oil consumption, etc, etc.

The price sounds fair enough; assuming they were needed and the problem is fixed.

This is a 1998 vehicle, at least 15 years old. It’s not at all surprising that it needs all of its oxygen sensors replaced. The sensors probably didn’t fail all at once, but one by one. Since the check engine light has been on constantly and you didn’t bother to read the codes and see why, there’s no way of determining when each sensor failed, not that it matters really.

The truck may have seemed to run well, as the computer can compensate for a lot of failures, but I’ll bet when you get them replaced that it runs a lot better and your gas mileage improves a lot.

I’ve never seen any experimental data on how long O2 sensors last. But from the comments here, around 130-150K seems to be where they start to be replaced. The one on my 200K Corolla remains original, and no problems to date. It’s possible I guess they don’t really fail, and all that’s needed is for them to be cleaned of surface contamination. But cleaning them may be easier to say than to do, and replacing is the better alternative. There are U2 vdos showing how to bench test O2 sensors using a propane torch and a dvm. Not sure how accurate the test is, but probably at least possible to tell if it is totally haywire or not.


“bench test O2 sensors using a propane torch and a dvm”

Whoever made that video had way too much time on their hands

You’re not supposed to clean O2 sensors

If they’re contaminated, you chuck them

But from the comments here, around 130-150K seems to be where they start to be replaced

I’ve never replaced one due to failure. Most of the vehicles we’ve owned went past 300k miles…a couple past the 400k miles mark.

Maintain cars well, don’t operate them while overheating etc. and there’s no reason to ever buy an O2 sensor short of some fluke failure.

I’ve never had to, or needed to, buy an 02 sensor for any of my cars or family members cars no matter the mileage except for one instance. That was due to a sudden O2 failure when a wrench slipped while doing maintenance and cracked the porcelain on the sensor after banging into it.
Since I was about to make a trip to the Pull a Part yard for some project car parts I just picked up an O2 there for 5 bucks and that problem was cured on the cheap.

@MikeInNh “I’ve never replaced one due to failure.”

It may be your cars are not as well engineered as Ford products. At one time ( many years ago) CR made the comment that a Ford product they tested had to be one of the best engineered cars of all time. Many parts seem to fail at the same time. I thought it might be a bogus comment until I had a long conversation with an engineer at a local plant which did subcontracting work for Ford among other automakers. Inferior parts on at least some occasions were required even though the price for better was the same.

The Ford Ranger may have been made under those “stringent” guidelines . My skepticism of auto part quality ( or lack of it) is reinforced over and over in my life time experiences with cars and those who make and sell them.

There’s probably a report laying around somewhere, where some scientist or engineer got hold of a large number of used O2 sensors from older cars and truck and bench tested them, and documented the failure rate vs mileage. I doubt they last forever, but how long they last on average, for now at least, remains a mystery. Measured data would be better, but it’s fun to speculate!

Guys, are you aware that O2 sensors slow down with age, just like we do?

Perhaps OP’s sensors haven’t outright failed. Perhaps they’ve just slowed down.

Good post @db4690. I know I’m feeling slower all the time! If the O2 sensor gets coated with contamination, it won’t respond to changes in O2 as fast as when it was new. That would prevent the ECM from properly regulating the air/fuel mixture. Sort of like if an expert tennis player suddenly couldn’t see as clearly as before, he’d have a harder time returning serves than he used to when his vision was 20/20.

@JoeTheAuthor…I highly suspect that only one of your O2 sensors was bad. Replacing all three is just “shotgun” maintenance for the most part. Big question…did your check engine light go out or is it still burning brightly on your dash? A lot of O2 sensors and catalytic converters are junked every day although they are still working fine.

Something that oblivion said earlier in this thread bears repeating:

“The sensors probably didn’t fail all at once, but one by one. Since the check engine light has been on constantly and you didn’t bother to read the codes and see why, there’s no way of determining when each sensor failed, not that it matters really.”

Ignoring a CEL for years means that some–or perhaps many–additional problems have cropped up since the CEL first lit up. Not taking care of problems as they occur–or at least checking the stored trouble codes periodically–will frequently lead somebody to believe that a lot of components failed “at the same time”, when–in reality–there was more likely an ongoing process of breakdowns that were not taken care of when they first took place.

Several years ago, a woman posted a question in this forum regarding her Suzuki, whose CEL had been lit up for 16 years without ever checking the stored trouble codes. The collective advice that she received from this forum was something along the lines of…Why suddenly worry about it now? Just continue to drive along on your merry way until the heap finally stops running. While that advice may have been less than helpful, it essentially summed up the frustration of trying to play catch-up on repairs after many years had passed.

Deferred repairs are never cheaper, and–in fact–may be more expensive in the long run than repairs that are done on a timely basis.