Jim Grant's Tech Tips
Mazda, O2 Sensor Switch
Q: I have a 94 Mazda and it just reached the 80,000 mile mark,
and my check engine light just came on. Is my reset screw in the same
place as the 89 Isuzu? Where is my oxygen sensor located?
Mazda is similar to the Isuzu in last weeks column. Yes you have to remove
the instrument cluster from the dash and reposition the reset screw to
turn off the Check Engine Light for another 80,000 miles. But there is
a catch with your Mazda. The computer can also turn on the Check Engine
Light. If moving the reset screw doesnt turn off your Check Engine
Light you may have a computer telling you there is a system problem. In
the early 90s Mazda was phasing out the use of mileage timers and
allowing the computer to determine when service was necessary. As for
the location of the oxygen sensor? Look for a part that looks somewhat
like a spark plug (its the easiest way to describe it) sticking
out of the exhaust by the exhaust manifold.