I believe you can get a Denso compatible one for $30....its almost not worth the effort to test a crapshoot old one. I'd just grab the new O2 sensor either way. Its something that if you plan to keep the car should be done regardless if you have no history. They last anywhere from 60-150k. I would assume most die early due to neglected valve stem seals leaking quarts of oil through the system.

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k