Should I change my O2 sensor at 252k?

I see no reason to incur the costs or risk of maintenance-induced trouble from preventive replacement of the heated oxygen sensor.

The sensor and its heater circuit are both monitored by the engine control module (ECM), which would set a diagnostic trouble code and turn on the malfunction indicator lamp (check engine light) in case of a failure. The car would still be drivable, but with the ECM running in open loop control mode without feedback from the sensor, its emissions might be higher and fuel economy lower until repairs were made.

Let’s apply Nowlan and Heap’s Reliability-Centered Maintenance precepts (United Airlines, 1978, p. xvii):

▸ Scheduled maintenance is required for any item whose loss of function or mode of failure could have safety consequences. If preventive tasks cannot reduce the risk of such failures to an acceptable level, the item must be redesigned to alter its failure consequences.

▸ Scheduled maintenance is required for any item whose functional failure will not be evident to the operating crew, and therefore reported for corrective action.

▸ In all other cases the consequences of failure are economic, and maintenance tasks directed at preventing such failures must be justified on economic grounds.
​

Clearly we’re in the third situation: if the sensor were to fail, the car would still be safe, and the failure would be indicated to the driver. Since the cost to replace the sensor would be the same, before or after a failure, which might not occur at all during the car’s remaining service life, there’s no economic justification.

 

it will not leave you stranded if they fail, worst a check engine light or rough running. Change it when you got a code.

 

I might look at fuel trim numbers in scandata. My 2006 at 200k is still running near 0%.

Maybe mode 06 data from the OBD2 monitor results. See how close the O2 tests are to their "fail" points.

For the most part as stated, the ECM will "let you know"when you need to replace the A/F or O2 sensors (at least 95% of the time).

Posted via the PriusChat mobile app.

 

Reliability-centered maintenance is a concept that’s now applied successfully in many industries. I cited the original report because it’s well-written and freely-available, and to properly credit its authors. Did you read it, or even just the abstract? Did you notice that an objective of the report was to be “a guide for application to a wide range of different types” of complex equipment, not just commercial airplanes?

I’m well aware of MSG-3 and later developments; the basic principles are the same.

 

it's very common for the heater circuit to fail on the OEM O2 sensors, the oxygen sensor itself is still working even at higher miles. My 07 Camry Hybrid still has the original front O2 sensors at 202k miles (16 yrs old) and I just replaced the rear O2 because of a failed heater circuit. Did it affect my driving or leave me stranded if I just left the heater circuit not addressed? nope.

 

I agree with the folks who say, no, it's one of the items that are on the "if it ain't broke don't fix it" list.

I do replace some things at 10-years because I know they are on the verge of going bad....spark plugs; PCV valve and the little hoses around it; gasoline refill cap; any coolant hoses that aren't looking good; serpentine belt if it hasn't been replaced; and radiator cap. (They get rusty inside after about 10 years.)

Good job taking care of you car....so many these days don't even give it a second thought. (I see way too many driving around with a near-flat tire or lights/blinkers out.)

 

Aaaaaand commence blocking srq lol