Code P0154 Persistent '96 Rodeo

[chaswe75]

I saw some other posts that were similar, but didn't cover this problem.
96' Rodeo 3.2 4WD 159,000 miles
I had an emissions test done and the results were:
P0157- O2 signal low B2 S2
P0420 - Cat Conv efficiency low bank 1
P0430 - Cat Conv efficiency low bank 2
P0401 - Insuff EGR flow
P1406 - EGR position chk problem
Both downstrem O2 sensors def. on scope, EGR full of carbon, not working

- replaced the bank 2 sensor 1
-replaced EGR

Reset the ECM, and now I am getting a P0154 from a new aftermarket 02.
Just to see if it was defective(I had bought 2), I put the other new one in, reset the ECM, and am still getting the code after many cycles. I checked all the wiring, cleaned and checked the terminals. Is there particular 02 sensor that this truck will only accept? I am pretty sure the cats are on their last leg. On a down slope, if you let off the gas, it seems like an exaust brake, and the codes for the cats are also good sign. My next thing is to at least replace the driver's cat. Any ideas would be appreciated, it needs an emissions pass.

[Cat Fuzz]

Swap the before-cat O2 sensors and see if the code changes. If so, one of the new O2 sensors is defective.

[chaswe75]

That was the last thing I attempted to do. Swap the passenger pre-cat 02. I didn't have the wrench to take down the front drive shaft or the patience hehe. I'll try that again. Thanks for the reply.

[chaswe75]

Alright, got the front drive shaft down and swapped the passenger pre-cat 02 with the driver one and am getting a P0134 code (bank 1 sensor 1 passenger pre-cat 02 no activity). I am assuming a brand new spliced universal 02 won't cut it for these Rodeos? Maybe a voltage drop or resistance from splicing. I keep hearing how this truck is an OEM snob. I'll try a name brand 02 with a wire plug and see what happens. Other than this, I can't complain about this truck. 159,000 miles, $500, she runs like a scalded dog.

[chaswe75]

OEM style sensor solved the problem. Good to know I have to replace the driver's cat now. Thanks a lot post-cat o2 sensors.