Multiple Fault Codes...Thoughts?

[2to4wheels]

So, some of you remember that I had some drama weeks back with a no start condition (thread link below). My '06 has been running fine since but did get a a CEL the other day. Finally scanned it today via Torgue and these are the codes it's reading. I haven't reset them and ran it to see if they come back but what do you make of this combination? Feels like it could have been related to the no-start.

P0131: O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1)
P0134: O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)
P0171: System too Lean (Bank 1)
P2195: O2 Sensor Signal Stuck Lean bank1 Sensor1

http://www.expeditionportal.com/for...-To-Me-Gen-3-Won-t-Start?highlight=2to4wheels

 

[Salonika]

I'd say not related......o2 sensors don't play a role in the start logic.

 

[2to4wheels]

I'd say not related......o2 sensors don't play a role in the start logic.

So you would assume the P0171 would be O2 Sensor related as well?

https://www.yourmechanic.com/articl...e-code-system-too-lean-bank-1-by-andrew-quinn

 

[Salonika]

Yes. What service history do you have on your o2 sensors? All of your codes indicate Bank-1 which implicates one side of your engine vs the other (I forget which is which). You could genuinely have a lean condition on Bank-1, or an out of spec sensor misreading the condition. Lean means too much oxygen in the mixture, but since it's only one bank it could be an exhaust leak on that side or a manifold gasket sucking air on just one side......hard to know for sure. With a service history though on the o2 sensors you could rule out mis-readings

 

[Salonika]

Reading the beginning of your previous thread......you said you smelled fuel during cranking when you had no-start......the only place you possibly should have smelled fuel would have been out the exhaust. Were you getting fuel smell under the hood? Lean condition on bank-1 might point to a bad injector seal.......a little fuel leaking out and a little extra air leaking in = lean sensor reading.

 

[nckwltn]

Check out this post and link to what might be your p0171 issue. Pretty easy to determine by shooting some carb cleaner into the area and listen for change in idle.


http://www.expeditionportal.com/for...71-and-sometimes-p0174-possible-fix?p=2210864

 

[2to4wheels]

Correct me if I'm wrong. Bank 1 Sensor 1 would be passenger side pre-cat?

 

[normal_dave]

Just thinking out loud...
http://www.expeditionportal.com/forum/threads/112384-2003-Montero-Limited-3-8L-fuel-filter-and-fuel-pressure-regulator

On my 3.5L. I replaced a perfectly good 02 sensor before discovering a bad EGR solenoid (not valve) upstream. Many similar codes will show up with a detached or damaged vacuum line, maybe a mis-aligned intake gasket etc.

How far in did you go on the no-start issue? Maybe a re-assembly hiccup? My advice, check upstream for issues first, then 02 sensors, as well as research the above mentioned TSB (technical service bulletin) on the fuel filter/regulator issues.

Edit, Bank 1 always matches the odd numbered cylinders, (in our case the passenger side), bank 2 even numbered cylinders. sensor 1=upstream before first converter, sensor 2=downstream before rear cata-(clys-mic) converter.