I bought a 97 Jeep Tj... on the way home the check engine light came on. I took it back and the dealer had his mechanic check it. He replaced the front (upstream) O2 sensor. Everything was fine. The next day the check engine light came back on...I did the code check on the dash...code 21 came up which indicates a O2 sensor problem...Now I see there are two O2 sensors...should I go ahead and replace the downstream (rear) sensor also ??? One site says something about 3 sensors...upstream..downstream and a left O2 sensor...so just how many O2 sensors are on a 97 Tj...
Thanks Bill
Thanks Bill