2020 Supra 3.0 - AA Catted Downpipe + BM3 Stage 2 OTS (Rear O2 Sensor CEL: 12AB04 / 12B701)

[pdxnkh]

Looking for some input from others who may have seen this.

Installed an Active Autowerke catted DP recently and flashed BM3 Stage 2 OTS (91). Followed the included catalytic break-in procedure to the letter. Car drives completely normal - smooth idle, full power, no limp mode, misfires, etc.

However, after about ~150 miles of sustained driving, I got a CEL with these codes:

• 12AB04 - Lambdasonde2 Bank1 electrical: line break
• 12B701 - Heating Lambdasonde2 Bank1: internal resistance too high
• 21B055 / 21B056 - AKKS internal communication errors (probably tune related and can be ignored)

Interesting parts:

• Cleared the codes and drove another 2-3 hours (broken up into shorter 30-45 minute trips each w/ full cooldowns in between) with no CEL return
• CEL came back again only after another ~3-4 hours of sustained highway driving (i.e. returns at the 3-4 hour mark)
• Seems very heat-soak/time related

One thing worth mentioning:
Initially after install I forgot to fully route the O2 wiring back through all the factory metal retaining clips near the heat shielding. I corrected that the next morning after the first CEL trip, but the code returned on my return ~3-4 hour drive. I inspected the wires, no thermal damage that I can tell.



When reading various forum posts on these codes/downpipe, it seems like this error can pop up if you gun it before letting everything get to temp...mine seems to be the opposite, only appearing at 3-4 hours of sustained driving in hot weather/heat soak territory. I've read thru the forums and see things ranging from "related to DP, the location of the bung was too close, they've redesigned it" to "install a new DP" to "try a new sensor", to "contact AA". I get a slight exhaust/gas smell at startup, but I think this is normal for the AA downpipe from what I've been reading.

Any ideas before I just throw a new sensor at it or file a claim with AA? I'm going to go on a few more drive cycle test runs to see if it self-clears. Again, car runs fine otherwise.

If you made it this far, thank you!!

Sponsored

 

[jmikes]

With my catless, 12B701 is the one I get from time to time and just clear with JB4. JB4 calls it "Lambda probe heating after catalytic converter". Usually comes on if I give the car too much throttle before it's fully warmed up (4 bars on engine water temp) but never comes on in any other circumstance.

Not sure about the other error, sounds like maybe the wiring for the O2 sensor got damaged or something during the install, but can't confirm.

The fact that yours is a catted DP makes me want to say go ahead and contact support through the vendor you bought it from and try to get a refund/replacement due to the 2nd error.

 

[pdxnkh]

With my catless, 12B701 is the one I get from time to time and just clear with JB4. JB4 calls it "Lambda probe heating after catalytic converter". Usually comes on if I give the car too much throttle before it's fully warmed up (4 bars on engine water temp) but never comes on in any other circumstance.

Not sure about the other error, sounds like maybe the wiring for the O2 sensor got damaged or something during the install, but can't confirm.

The fact that yours is a catted DP makes me want to say go ahead and contact support through the vendor you bought it from and try to get a refund/replacement due to the 2nd error.

Yeah - 12B701 is the one where I'd think it would come from what you described...but instead it's happening for me 4 hours into a drive and not under any other condition (even if I get on throttle early on a cold start for a 30 minute drive or something). So odd.

Ya, will probably end up filing something with AA..ugh!

 

[pdxnkh]

Update:

the CEL went away on its own after 2 more 30 minute drive cycles. On the 3rd start it was gone.

I think the only way I can replicate is a 3+ hour drive.

Sponsored