The sealing rings are synthetic resin with chamfered ends. Check the condition of the sealing rings, and replace them only if they are worn, distorted, or damaged.
For a better fit, squeeze sealing rings together slightly before installing them.

Apply ATF to the new sealing rings, then install them on the secondary shaft.

After installing the sealing rings, verify the following:
The rings are fully seated in the groove.
The rings are not twisted.
The chamfered ends of the rings are properly joined.
Introduction
Congratulations! Your selection of a 2008 Honda Fit was a wise investment.
It will give you years of driving pleasure.
One of the best ways to enhance the enjoyment of your new vehicle is to read
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Secondary HO2S Replacement
Special Tools Required
O2 Sensor Wrench Snap-on S6176 or equivalent, commercially available
Disconnect the secondary HO2S connector (A).
Raise the vehicle on a lift.
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Customer Service Information
Honda dealership personnel are trained professionals. They should be able to
answer all your questions.
If you encounter a problem that your dealership does not solve to your satisfaction,
please ...