Product review (5 stars): Checked everything.  Occam's Solution proves to always be the best.
Our Kenmore Elite HE5t steam HE washer  (aka Whirlpool Duet)  was throwing SUDS / F35 errors after 10 years of regular use with HE detergent.  On Youtube you find various remedies including replacing the rubber hose, replacing the 2200uF/10V capacitors on the CPU board, cleaning the sensor with brake cleaner / alcohol, cleaning out the air chamber (where the sensor hose connects to the drum), and cleaning out the sump filter at the bottom.  My sump was clean, the hose was intact, the air chamber was clean... so I replaced the 2200uF capacitors with 25V versions.  Didn't fix (didn't hurt).  Then I hooked up a clear vinyl aquarium hose to the sensor and was able too get it to pass diagnostics C:00 by blowing hard on it at certain times in the cycle.  Flushed sensor out with isopropanol twice, but only temporary fix.  Tried brake cleaner, again only temporary.  Error returned.

So sprung for it on Prime.  Delivered in 2 days. Replaced with this sensor and BADA-BING!  Fixed. No errors.