Please help! - Lean code P2098

SonicVQ · 05-01-2020, 10:19 AM

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!

chalmene · 05-01-2020, 10:47 AM

Quote:

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!

I have replaced the clutch and flywheel, is there something I could have done wrong that threw off the timing?

INFmstrTech · 05-01-2020, 10:54 AM

Quote:

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!

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.

chalmene · 05-01-2020, 11:09 AM

Quote:

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.

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

INFmstrTech · 05-01-2020, 11:24 AM

Quote:

Originally Posted by chalmene

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

It would be downstream. Instead of watching bank1/2 sensor 1 watch bank1/2 sensor 2. Sensor 1 is upstream, sensor 2 is downstream

05-01-2020, 10:19 AM	#1 (permalink)
SonicVQ Base Member Join Date: Jan 2016 Location: Ontario Posts: 232 Drives: G37 Sport Rep Power: 6721	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! JARblue and Ghostvette like this.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Got P2098 Bank 2 Lean	370zBoyz	Engine & Drivetrain	7	12-07-2019 07:09 PM
CEL Code - P2098	drentooth	Nissan 370Z General Discussions	2	04-24-2019 01:56 PM
Codes p2096 and p2098	F3rron55	370Ztune	3	02-25-2018 06:03 PM
Engine Code P2098	littlejuanito	Tuning	7	10-09-2017 07:41 PM
P2096 and p2098 codes	Zero dark	Tuning	1	08-19-2015 01:33 PM