[Lewis T.]

I need help! My sienna 2000 was leaking oil through the head gasket. After replacing the head gasket and driving about 5 miles, the engine light came on. Mechanic checked and said A/F sensors failed (P1130, P1135). Removed and reinstalled the fuse, the engine light went away but came back on after driving a few miles. Could both sensors failed or something else?

 

[TrailDust]

Those codes indicate a malfunction with the AF/R sensor Bank 1/Sensor 1 that's located near the firewall in the exhaust manifold. You mentioned "removed and reinstalled the fuse," but did you replace the actual B1/S1 sensor?

 

[Lewis T.]

No, I did not replace B1/S1 sensor yet. I saw the Denso A/F sensors 234-9007 and 234-9009 on Amazon but was not sure it they are the correct A/F sensors to buy. I am confused. Where is the firewall? I see one sensor in the front, right side of the engine. Is it one of them? Thanks.

 

[TrailDust]

Sorry for the late reply. Try this diagram:

 

[Lewis T.]

Great help with the diagram. I ordered the parts. Hope it will fix the problem.

 

[Lewis T.]

Replaced front air fuel sensor with Denso 234-9009 and rear air fuel sensor (near firewall) with Denso 234-9007. Engine light went away. Guess it fixed the problem.