high miles 2011 xc90 3.2L rich/lean

Post by **abscate** » 09 Aug 2025, 15:17

ikeever · Post by **ikeever** » 22 Sep 2025, 16:08

Put on 4 new denso oxy sensors, ….again. Only code now is p0430. Bank 2 cat. Still smells rich…
Long/short trims all normal around 3-5%…

2 new aftermarket cats installed.

Bank 2 upstream voltage is steady at .95-.99 volts, and bank 2 downstream cycles up and down from .3V to .7V.

stubbornly still throwing the 430?

ikeever · Post by **ikeever** » 02 Oct 2025, 16:23

Update: I've finally fixed it. The initial 2 upstteam lambda sensors (A/F) sensors I put in, came in Toyota boxes... but had the correct Denso part number on them. I put 2 new upstream A/F sensors on it from FCP euro, and it fixed all my problems. All indications, including Denso website, say they cross... I don't know, my Volvo XC90 didn't like them. Both types of sensors showed normal values plotting in VIDA

Good part from FCP Euro lamba A/F sensor: Denso box; DOX-0526, no number stamped on actual sensor.
Bad Part XC90 didn't like: Toyota box with 234-9151, Denso 30713864 and 234-9151 stamped on sensor.

All those numbers cross.... so I have no idea. But it runs great now, no lights or codes. Didn't have to go to the dealer.