Down stream o2 sensor

Maintenance/Repairs
1

CAN AN O2 SENSOR BE CLEANED AND RETURNED ON A 98 GRAND CHEROKEE LTD ? I AM REITRED AND ON FIXED INCOME AND CAN’T REALLY AFFORD A NEW ONE, UNLESS I HAVE TOO. THANKS

JACKMG

2

No. They can’t be cleaned with solvent, brushes, or such ways. Sometimes, if a lot of short trips have caused deposits to form on an oxygen sensor, a long drive on the interstate may get the deposits hot enough to burn off.
Why do you think the downstream O2 sensor needs replacing? I hope it’s not just because a trouble code scan had the words “down stream O2 sensor” in it. That’s not sufficient reason. There are other things, and tests to do, first.

3

Hi, I went down to my dealership and they put the computer on and it read rear 02 sensor also the check engine light stays on.
Thank you.
JACKMG

4

Cleaning it has some effect but not anything that fixes the problem, even temporarily. The downstream one probably has less effect than the upstream one.

5

Did you pay for something that you can get for free at many auto parts stores? If the check engine light comes on, many auto parts stores will scan the engine computer and get the trouble code, free. The trouble code says that there is a problem in a CIRCUIT (like, in the oxygen sensor CIRCUIT) of which the oxygen sensor is a part of. Very unfortunately there are many (otherwise) good mechanics who don’t seem to realize this. Who pays dearly for this ignorance? You guessed it: the customer!
Unless the truck has to pass an emissions test, you don’t need to get the down stream oxygen sensor circuit fixed, today; but, don’t forget it.
The down stream oxygen sensor is designed to indicate when the catalytic converter is not operating properly. The catalytic converter may be stuffed with soot from a poorly tuned engine; or, an internal antifreeze leak; or too much motor oil being burnt in the engine. It’s possible the oxygen sensor has been eaten away by the exhaust gases.
What can you do? Keep the engine tuned with fresh spark plugs, pcv, and clean air filter. You can have an auto parts store scan the engine computer, and bring that trouble code here for advice. There’s somebody “here” 24/7.