Defective oxygen sensor in 97 Explorer

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Jun 8, 2006 | 08:45 PM

mark b

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Defective oxygen sensor in 97 Explorer

The check engine light was coming on periodically at highway speeds in my 1997 Explorer (4.0L V6 SOHC, 91,000 miles). I hooked up an OBD-II code reader and got a P0153 code. The software says I have a defective oxygen sensor (stuck lean) on Bank 2, sensor 1 (upstream). Am I correct in thinking that Bank 2 is on the opposite side from cylinder No. 1 and the upstream sensor is the one closest to the exhaust manifold?

Mark B.

Jun 9, 2006 | 07:47 AM

ajguzik

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You are correct. Bank 1 is on the passenger side, Bank 2 driver's side. The sensor is in the Bank 2 exhaust manifold, and should be accessible from under the Exp.

Apr 22, 2017 | 07:10 AM

zebra99

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trouble code p0420

I have a 1997 explorer with 4 liter SOHC V6 with 140k miles on it.

Problem starts out as a pending code P0420 then after a time lights the service engine light. Erasing the code just causes the problem to repeat. The code indicates a weak catalytic converter. Could the real problem be a weak or defective oxygen sensor?

Apr 22, 2017 | 03:44 PM

85e150

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Welcome to FTE.

I can't tell you one way or the other, but I do know that intake leaks will cause a "lean" code and are many times thought to be bad sensors.

The intake O-rings are trouble. Cracks are not unheard of either.

Running it lean or with a miss will eventually kill the cat, so IMO it's worth running down the intake and any lean codes when you get a code like yours.