o2 censor

my 98 has a po138 service code o2 sensor before converter where is this sensor and was the code correct i was told the 98 xj has 3 sensors is this correct thank you

98 should have two sensors, one pre, and one post cat.

P0138 should also be a code for the post cat. sensor.....i've been chasing the same one for about a year now on mine....

If you see 3 then your XJ very likely has CA emissions...meaning four O2 sensors. I thought I counted 3 until I found the fourth. The upstream pair are under the exhaust manifold and the 2 downstream sensors just after the minicats (those 2 bulges at the beginning of the exhaust pipes.

Otherwise if you have "Federal emissions" there are only 2.

i went with the flo pro cat back tim

dcaa4 said:

i went with the flo pro cat back tim

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You lost me....lol