1997 Toyota 4Runner Replace O2 Sensor
One do-it-yourself auto repair that can save you a good deal of money is to replace an O2 sensor on your 1997 Toyota 4Runner. There are two oxygen sensors on the truck, both of which are used to gauge the oxygen/fuel ratio. A malfunction of either of these sensors is a common cause for the "Check Engine" light to come on. Most retail auto parts stores can run a simple and free diagnostic test that tells which of the two oxygen sensors you must replace.
|12 mm wrench|
|Liquid Wrench or other lubricant|
|Replacement oxygen sensor|
Replace O2 Sensor
- Crawl under the 4Runner from the passenger side right behind the front tire. The two sensors are on top of the exhaust pipe: one on each side of the catalytic converter. Use a 12 mm wrench to remove the two nuts holding the sensor's mounting bracket in place. It's possible the nuts may be very tight. If so, spray first with Liquid Wrench or similar lubricant, wait and then try again.
- Use your finger to trace the wire to the plastic connection plug. Use a flat-head screwdriver to push down on the clasp, and unplug the connector.
- Place the mounting bracket on top of the exhaust pipe and screw the nuts back into place, fastening tightly.
- Plug the plastic fastener connection together.
Tips & Warnings
- Replacement oxygen sensors generally cost $75 to $95, depending on the retailer.
- Make sure the 4Runner is in park. Also, apply the emergency brake before you start work.