Oil wicking into ECM - random A/F sensor codes P0171/P0174/P2195/P2197 (1 Viewer)

[white_lx]

Quick update. First test drive results look promising. Here is a part of a data log of the total fuel trims (STFT+LTFT) for both banks (logging with Tactrix Openport). No longer any strange excursions from the 'normal' values.

 

[masturv8]

Just read this thread, wild. I had no idea this was possible.

 

[BoostinZX]

I still haven't started replacing mine, but thank you for being so thorough on your posts! Any update? fuel trims still looking good? And care to share the 3d print for the A/F connectors?

 

[white_lx]

I still haven't started replacing mine, but thank you for being so thorough on your posts! Any update? fuel trims still looking good? And care to share the 3d print for the A/F connectors?

Everything looking fine so far. I have not yet connected a scan tool to see if there is any fuel trim creep, but I don't smell the rich exhaust anymore. It has been running great. Probably put around 1000 miles on the vehicle since (don't drive it a lot).

Once diagnosed, it was actually a pretty easy fix. By replacing the internal transmission harness the wicking should have stopped. Without the pumping action, the ATF might just remain in between the wire strands. I did leave the A/F sensors unplugged for a few days during the repair and the connectors stayed dry after cleaning them out.

Sure I can share the 3D print. Not sure how to. Email? I'll pm you my email address.

 

[Anomic]

A big thanks to everyone here. I have had a saga of similar issues, I fired the parts cannon based on different codes and engine behavior before finding this thread. What a relief to pull the locking handle on the transmission wire harness and pull it out to see transmission fluid literally drain out of the wire harness. It was like popping a blister after a 1/2 marathon in the same sense that the healing can start. Parts arrived this week and I started working today. Got the wire in and put a new filter and gasket while I was there. 2 of 20 transmission pan bolts were broken when I bought my 2005 GX470 (215K miles, nav, air shocks deleted, fairly stock no big mods) and I managed to break a few more despite a long soak and hand removing bolts so I just ordered 20 new ones. Maybe the last guy to drop it didn't use a torque wrench or I just bad luck but the broken ones will be easy to remove.

One tip I want to share is: I stacked 3 pool socks in the nozzle of my shop vac and taped them down. I then pulled wire harnesses at the ECU and vacuumed a surprising amount of transmission fluid out, the pool socks were used to catch the fluid without restricting the air flow and they did a great job. I'm repeating this vacuuming at different sensor wire connections in the next few days in the hopes of 'drying up' the wiring enough so there are not more issues in the future.

If I have to do this job again I'm definitely removing the shaft in the way of the connector bolt, I wear a XL glove size and barely reached up in there to get the job done. I took photos of the wire routing per suggestion here and it saved me from doing it wrong, so I second that suggestion. The rest of the job went fairly easy.

I can't wait to get back behind the wheel, hopefully my bolts from Lexus Parts Now get here in a reasonable time.