I have a 2002 Explorer 4.0L V6. Recently it was having trouble shifting 1 to 2 and gave me the dreaded flashing O/D light, and a P0775 DTC. After some research I was able to determine the OD servo was the issue, I have fixed it and now she shifts well. However, I seem to have created a new problem...

I am getting the P1131 and P1151 codes which are telling me the HO2 sensors are not switching and she is running lean. This makes her tend to lope at idle.

Now before I fixed the OD servo, this was not an issue, and after the repair it was, and as part of the repair process I had to disconnect the exhaust system at the manifolds and muffler so I could have enough room to get to the servos, and I had to disconnect the O2 sensors. Because I am seeing codes for both banks it seems less likely that its a HO2 sensor failure and more likely that there is another issue here. I have not crawled back under the truck yet, but I will take a look at the sensors to make sure the have good connections, I was thinking that maybe in my haste to finish the OD servo repair perhaps I did not get the exhaust properly seated on the manifolds so perhaps this is allowing air in to the stream and giving the sensors a bad read.

I'm just thinking out load here and welcome any thoughts or insight, I am convinced I created this issue during the servo repair, but I'm not sure exactly what I did/didn't do to create it.

Thanks

 

If there is any leakage (illegal air) upstream of the B1S1 or B2S1, what you describe will be the result.

 

exhaust leaks. both sides. probably didnt button everything up or maybe if it was the first time being disconnected the seals aren't what they used to be.