P-0031 Code Solution in 3.4L Tacoma

Hi - I'm Dave and live in Saugus, CA, driving a 2004 Tacoma extended cab 2-wd with 3.4L engine. Purchased this truck new in So. California, it now has 114,750 miles on the odometer.

Three weeks ago, the CEL threw a P-0031 code, indicating a bad up-stream A/F Sensor. The bad sensor Toyota p/n 89467-35060 was removed. The OEM replacement starts at $196 on Amazon, $280 at the dealer, but many vendors on Amazon, Ebay, auto parts stores and posts state that the Denso p/n

$146 234-9001 Upstream Air Fuel Ratio Oxygen Sensor with 10.6” 4-Wire Harness, for Auto Trans Equipped Vehicles

234-9001 is a valid replacement for the OEM Toyota part. NOT so.....

I purchased the Denso part and installed it. The truck CEL extinguished, but the engine surged and pulsated at all speeds. Not good. A replacement Denso unit was sent, installed, and with the same results. Not really driveable, but the CEL lite was OUT.

Last week I bit the bullet and ordered the OEM Toyota part number 89467-35060 for almost $200. In ten minutes it was installed and the truck runs like new.

Hope this helps someone in a similar predicament.

 

Welcome!

Glad you got it figured out!

 

Welcome to TW!