99 SOHC-check engine/right bank rich

[Van]

My check engine light came on today.
A stop at Auto Zone and the guy said "rich right bank".
He says driver's side. O2 sensor.
Opened the hood but didn't see an O2 sensor on the driver's side.
I'm just out of surgery on Monday and on meds, so excuse me if this isn't clear.
Any idea what this fault could be would be appreciated.
Thank you.

 

[PopRichie77]

There are 2-- O2 sensors mounted in the pipe, they are under the truck.
Passenger side is the right side.
Driver side is the left.

 

[Van]

So, the right bank would be the passenger side?
I suppose with 93k and being 12 years old, it's not hard to imagine an o2 sensor being kaput.
Thanks for the response!

 

[RomeovilleIL]

If your chech engine is still on, you should ask them to print out the error code and post it here. Rich error might be a bad O2, but just as often its something else being read by the sensor. How is the engine running?

As mentioned above, right bank is passenger side of truck. There are in fact 4 O2 sensors on the truck. Two upstream (left and right sides) before the cats and 2 downstream (left and right sides) after the cats. A bad O2 sensor is usually identified by bank number and position - such as bank 1 sensor 1 is left upstream. The sensors are about $50 and you want to be sure you buy the correct one. Recommend you pick up an offset O2 socket for $12 in the helper tools. It looks like a black figure 8 with gaps for the wiring - makes changing out very easy.

 

[2000StreetRod]

bank 1 same side as cylinder 1

The numbering convention for bank 1 is the same side as cylinder 1 so bank 1 is on the right (passenger) side.

 

[Scaboza]

Did they say what the code number was? Mine said the same thing but the code number was 412 (I think that was the number) which is the catalytic converter. Of course part of the troubleshooting includes checking the o2 sensors I'm told.

 

[Van]

Thanks for the tips.
I removed the battery cable and left it off while I cleaned the MAP and air filter.
Drove it twice today, and the light stayed off.
I'll wait until it comes on again and have them give me the code(s).
It runs just fine. No hesitation or roughness.
Starts right up.