still no data from new o2 sensor

2008 mazda 5
my 2008 mazda 5 threw a p2177 - "System Too Lean Off Idle Bank 1" couple weeks ago. The Torque app (android app that reads from the bluetooth odb2 reader) also shows there's no data from b1s1. Ordered a denso sensor (same as the old. 5 wires: grey, black, white, yellow, blue ) and installed it today but app still says no data. any idea? I have a multimeter but not sure which wires to probe for resistance test. Any fuse I need to check? thanks

see attached.



Last edited:


2009 Mazda 5 GT - 5-speed MT
Hey '08, have you solved this yet? I recently replaced the O2 sensor in our '09 (on the basis of mileage, not because there was a code thrown). I checked the resistance between the pins on the connector, with the following results:

YL - BL = 2.7 Ohms (I would guess that this is the heater circuit.)

All other pin-to-pin measurements indicated infinite resistance (that is, an open circuit).

So, checking the sensor with an Ohmmeter is not that helpful, other than for diagnosing an open heater.

Good luck, and please let us know what it was.