Repair 7

How to Replace the Oxygen Sensor on a Toyota Sienna

Replacing an O2, or oxygen, sensor in your Toyota Sienna involves removal and replacement of as many as three sensors in the vehicle. The sensors are not all going to fail at once, but they will all produce the same symptoms. So before you pull any of them out of the van, visit an auto parts store or dealership and ask them to scan the computer on your van to determine which sensor is failing. Replacement sensors are available from Toyota or most auto parts retailers and can be costly to purchase.

Instructions

1

Raise the hood of your Sienna and locate the two sensors in the engine compartment. There is one in each exhaust manifold on either side of the engine. The third sensor is located under the van just downstream of the catalytic converter and can only be accessed from under the van.

2

Locate the wiring harness on the top of the O2 sensor and follow it back until you locate the connector where it joins the main wiring harness. Release the locking tab on the connector, then separate the two halves.

3

Install an O2 sensor socket on the sensor, then turn it counterclockwise with a ratchet until it is loose enough to remove. Discard the old sensor. Thread in a new one and then tighten the sensor with the O2 socket and ratchet.

4

Run the wiring harness to the connector on the vehicles main wiring harness and push the two connectors together. Make sure the locking tab engages and the two connectors are secure.

5

Raise your Sienna with a jack and position a set of jack stands under the front suspension to support it. Slide under the vehicle, locate the O2 sensor right behind the catalytic converter, and repeat the same process you used under the hood to replace the other sensor if required.

6

Raise the Sienna off the jack stands with your jack, remove the stands and lower the van to the ground. Remove the jack from under the vehicle then close the hood.