Please help! - Lean code P2098

Originally Posted by SonicVQ

Here is what I see:

• The fuel trims are within the normal range - good!

• O2B2S2(V) / O2B2S2(V) -> this is the rear o2 sensor voltage. A single "snap shot" of this data doesn't tell us anything. A datalog of about 1-2 minutes does tell us a lot, but I suspect your OBD tool doesn't have that function.

• Cat temps: This is a calculated value based on engine demand. It doesn't really tell us anything for this issue.

• EQ_RATB1S1 = 0.996 / EQ_RATB2S1 = 0.975: This is the equivalence ratio (aka lambda). Multiply it by 14.7 to get the air/fuel ratio. (bank 1 is ok, bank 2 is a little rich)


• O2[b]B1[\b]S1(V) = 2.29 / O2[b]B2[\b]S1(V) = 1.905 / This is the output voltage from the air fuel sensors. At idle / low engine load (air/fuel ratio of 14.7) they should be 2.2 volts. Bank 1 is a little lean bank 2 is a little rich.

As you can see, the data contradicts the trouble code.

Keep in mind the data above is a "snap shot" in time. Often the engine computer will adjust up and down and then perform an analysis to determine a average. If the average is out of a predefined range, a trouble code will be set.

A common cause for one bank to be rich and one bank to be lean incorrect crankshaft/camshaft timing. Luckily, this doesn't normally apply to out engines.

I think it is best to take it to a shop. To continue to trouble shoot requires special tools and knowledge, as I see it.

Maybe someone else will see something I missed. - Good luck!

Originally Posted by INFmstrTech

I would watch b2s2 and bank1s2 on your scantool (that’s the actual o2 sensor) from your post it looks like you’ve replaced the a/f sensor (b2s1). If you can graph both rear sensors and hold rpm steady at 2500, or have someone drive with you watching the line graph there should be even waveforms at steady rpm. If bank 2 o2 is switching to fast or slow compared to bank 1 I would suspect a bad o2 sensor causing the P2098 code. Very common for that to happen.

Originally Posted by chalmene

Ok, I will work on that and reply back. Which o2 sensor is that? Downstream or maf sensor? Bank 2?