Dreaded p0430 code and downstream O2 sensors reading zero (1 Viewer)

Joined
Dec 30, 2019
Messages
90
Location
Austin
I replaced both downstream O2 sensors. The p0420 code went away. The p0430 (passenger side downstream) code had gone momentarily and has come back.

I know cats are good. Whats strange is that the O2 sensor output is zero. I am using Denso and not Toyota.

Any tips?
 

empty80

SILVER Star
Joined
Sep 18, 2016
Messages
474
Location
ABQ, NM
Did you use the same part number for both sides? The parts catalog shows different part numbers for the rear right and rear left.

Denso parts should be fine unless it is faulty. If you have a ohmmeter you can test the sensor itself. It’s normal conditions should be between 37-44 ohms.
 
Joined
Dec 30, 2019
Messages
90
Location
Austin
Did you use the same part number for both sides? The parts catalog shows different part numbers for the rear right and rear left.

Denso parts should be fine unless it is faulty. If you have a ohmmeter you can test the sensor itself. It’s normal conditions should be between 37-44 ohms.
Cannot use same part on both sides as the connectors are different. I used the correct parts on both sides. From what I am reading Zero voltage means engine is running lean.
Any idea where the relay might be?
 

empty80

SILVER Star
Joined
Sep 18, 2016
Messages
474
Location
ABQ, NM
Zero volts under which operating conditions, and how did you take that measurement?
 

empty80

SILVER Star
Joined
Sep 18, 2016
Messages
474
Location
ABQ, NM
I measured the voltage via ODBII. Zero voltage while idling.
Apologies on the previous resistance values. I quoted the VSV values. The proper values for Sensor 2 11-16 ohms. Signal comes from ECM with no intermediate relay.

I’m not sure how all the OBD2 measurements stack up, but when measuring voltage of a circuit, the voltage measured across a components is a voltage drop, or the amounts of voltage the circuit loses due to resistance within that one components. In a simple DC circuit measuring 0V means something isn’t reading resistance in that component. Presence of the ECM muddies the waters a bit. I would recommend resistance test across the sensor as next step, and a good once over the wiring harness in the immediate area to ensure there isn’t damage.
 
Joined
Dec 30, 2019
Messages
90
Location
Austin
Apologies on the previous resistance values. I quoted the VSV values. The proper values for Sensor 2 11-16 ohms. Signal comes from ECM with no intermediate relay.

I’m not sure how all the OBD2 measurements stack up, but when measuring voltage of a circuit, the voltage measured across a components is a voltage drop, or the amounts of voltage the circuit loses due to resistance within that one components. In a simple DC circuit measuring 0V means something isn’t reading resistance in that component. Presence of the ECM muddies the waters a bit. I would recommend resistance test across the sensor as next step, and a good once over the wiring harness in the immediate area to ensure there isn’t damage.
There is no 0V anymore. It was misunderstanding on my part of operating temperature. After the engine is hot the reading of O2 sensor has started.

it’s very jagged. Someone in Tundra forums said that Toyota sensor fixed for them even though they are Denso they might different tolerances.

Also, the 2013 and Newer have much tighter tolerances than models before so any small change throws code
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top Bottom