P219A & P219B

Hey there, I got a 2015 4.0 with about 205,000km on the clock, vehicle has been nothing but good to me since ownership at 35,000km. I have a full afe exhaust system from the headers back and afe Intake system as well on the vehicle since roughly 50,000km. I just got a CEL for 219A and 219B, air to fuel ratio imbalance between bank 1 and 2.

So far I've cleaned my MAF sensor, checked for vacuum leak, checked spark plugs ( which have less than 30,000km, iridium) changed air filter, checked purge valve, still getting the code. The vehicle runs completely fine, no misfires, no power loss. Yes I've cleared the code multiple times and they both come back. Both my 02 sensors and AF sensors upstream are original, but i find it hard to believe bank 1 and 2 failed at the same time.

I've attached some freeze frame data if that helps, hope someone can point me in the right direction

 

Those codes can be difficult to track down as there are alot of variables involved and service info isn't really clear on what exactly it's looking for to set those codes.

Have you verified you have no exhaust leaks?

Does the freeze frame show the RPM and Vehicle Speed when the codes set?

Can you look at live data and see what the AFR, O2, Long Term, and Short Term fuel trims are reading? It's possible you have a biased AFR sensor.

 

I got tons of live data, my AFR sensors both showing 2.9 on idle, the vehicle was driving highway speeds around 65mph

 

Something is off there, they should be right around 3.3v

 

That's what i read. But when I do the injector test and prompt it to run either lean or Rich, the AFR sensors go down and up accordingly, but on idle their at 2.9. My issue is did both AFR sensors really fail simultaneously? And not to mention, to the exact same threshold?

 

I guess it's possible, AFR sensors are kinda difficult to check for being biased.
Sometimes you can use the downstream sensors but it's not a very accurate way.

I've seen this before on Fords but haven't seen it on a Toyota yet.

Often when Toyota sensors get biased they bias lean and cause the downstream sensors to read high and they set a code for the downstream sensor.

Yours appear to be biased rich but it's hard to say for sure.

 

Been fighting this for about 3 weeks now. The afr sensor are 2.9 on idle but 3.3 on ignition on. I just did a full compression test as well 193-195 across all cylinders. I'm honestly stuck

 

I'm not usually one that fires parts but if everything else checks out and they are original I think I'd put a set of Denso AFR sensors on it and see what happens.

Have you checked that you don't have any oil leaks leaking onto the sensors? I have seen that cause them to drift or stop working.

 

I pulled bank 2 sensor, and while it was just your standard amount of dirty for a 200k vehicle it wasn't oily. It's worth mentioning my mpg is also pretty bad now so certainly running rich

 

Unfortunately this is typically valves, or cylinder carbon.

A borescope with side camera would be my first step honestly.

The last imbalance I did was heavy carbon caused by EGR (which 1GR doesnt have) but it was straight forward once I was able to see inside the cylinder.

The exhaust leaks typically cause AF slow response or P0420 we've found, but the aftermarket exhaust could have impact on the combustion.

Lets say you confirm carbon, you could go hard and do a hot seafoam flush through intake.

 

Wouldn't think carbon would be much an issue on a 4.0 being it's port injected and doesn't have EGR but yea wouldn't hurt to take a peek with a borescope and/or do a leakdown test.

DI engines yea carbon buildup is a huge issue.

 

Just for reference here's a known good capture from my truck, cold start and driving.

 

We had a 4.0 Propane that ate a valve last month, I did the head gasket on it 2 years prior and it was the cleanest engine I've ever seen, but famously propane destroys valves over time.

Like I said I'd want to look first, its a bastard code.

 

I've never seen a propane conversion on anything, a couple fleet companies i know used to run propane around here but it costs more than gasoline now so no one uses it for anything other than heating and standby generators.

 

Wouldn't I see a valve issue on the compression test I did? The only thing that was a fail was my af sensor determination bank 1 and bank 2, as per the monitor, and the threshold it went over was a 0.06 and 0.03 as far as the allowable tolerance. I don't know how to interpret anything else on the freeze data

 

Guys,

I have a P219B Code - Bank 2 Air-Fuel Ratio Imbalance. I'd like to replace the AFR sensor on Bank 2 but I do not know what side is Bank 1 or Bank 2.

P219B Code - Bank 2 Air-Fuel Ratio Imbalance

 

Bank 2 is driver's side.

 

Heres some foresight, your code is unlikely your actual Air fuel sensors, after many diagnostics, I found my issue was actually a pin hole leak on the Air fuel sensor bung where it goes into the exhaust.. Aftermarket AFE headers caused all my grief