Mathiaso: One More Question re Sienna 1130 and 1155 Codes


Thanks for your detailed response to my question about Sienna P1130 and P1155 Codes, but I have one more question.

Earrlier you wrote:

“The air/Fuel ratio sensor (A/F) is is referred to as a wide range or wide ratio sensor because of it ability to detect air/fuel ratios over a wide range. The avantage of using the A/F sensore is that the ECM can more accurately meter the fuel reducing emissions. To accomplish this, the A/F sensor:
- Operates at approximately 650*c, much hotter than the oxygen sensor 400*c
- Change its curent output in relation to the amount of oxygen in the exhaust stream.
The A/F sensor voltage output is opposite of what happens in the narrow range oxygen sensor. Voltage output through the detection circuit increases as the mixture gets leaner. This is brief description of the A/F sensor. As A/F sensor and oxygen sensor work together, a lazy oxygen sensor taking longer time to switch from rich to lean or vice versa can affect emissions. Check the oxygen sensor itself, and you will need a diagnostic chart to do the rest of the test. Check the oxygen sensor heater circuit. The heater element resistance can be checked with a DVOM. Mesure the voltage signal of the A/F using OBII The A/F sensor curent output cannot be accurately mesured directly. Good luck.”

Very informative, but here’s my additional, possibly stupid, question:

Are we talking about two separate sensors here, or are these just two codes referring to one possible malfunctioning sensor? Looks to me like there are three oxygen sensors - two in the exhaust manifold and one near the CC. Which one(s) am I talking about here?

Thanks again!

Do you
have the same problem?
Wednesday, January 10th, 2007 AT 10:51 PM

1 Reply

Sorry I did not see your post.
Yes you have two oxygen sensors in the exhaust manifold and one heated oxygen sensor( A/F) near the CC
Was this
Friday, January 12th, 2007 AT 11:35 PM

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