Reccuring P2197 code is driving me nuts

My driver side air fuel ratio sensor was contaminated with some ATF residue from a tranny flush I did recently. The hose slipped off and went puking out ATF, the skid retained some of it... anyways, moving on..

Long story short I ended up replacing the sensor. It was a pain in the ass to remove alone and I had to pull on the harness a little to get the sensor plug to come off it. Now the code has been happening sporadically. It went away for what seems like a month, then suddenly it came back hard and keeps returning. P2197 Bank 2 Sensor 1 stuck lean. I go and check readings on the sensor. It is fine and it reads back within normal ranges similar to Bank 1 Sensor 1. Just for kicks I smoke tested the engine, fine. Then I checked and cleaned the MAF. It was a little dirty, but nothing major.

I have no idea what the hell is going on. Did I possibly damage the harness? It was so hard to get to it, so I really dont know how I am going to go about fixing this if it is damaged.

Some suggestions would be more than welcome.

 

Hey @BamaToy1997, got any input?

 

Hey @Torspd. I have a URD intake. I read that their MAF extension harnesses have been known to have problems. Could this be causing my random and sporadic lean outs?

 

Do you have the shield over the intake?

 

Yes I do. Is that anything of relevancy? Interference?

 

That bank is lean as you know, Have you sprayed some brake clean or similar at intake gaskets while ideling on that side to see if rpm changes?

 

I did a smoke test on it and the system is sealed. Good to go. I'm actually leaning more towards the MAF. I get the feeling something there maybe at the connections is wonky. Because the truck runs fine and feels fjne, then suddenly it freaks out out of nowhere and starts running a little rougher then the CEL sets on and I get open loop conditions on both banks.

The plug and harness to the af sensor is fine, as it is always working and I do not see a voltage dropout at any time during monitoring of it.

 

No other replies? @Torspd you will probably be my biggest aid here. Where you at bud?

 

Shhh.....I'm spleeping.....shhhh

 

Being as that is where the problem started, then I'd stick with testing of that sensor first.

Try swapping the Driver side WRAF sensor with the passenger WRAF sensor. See if the code moves or stays on the same bank.

If it stays, then it is possibly the harness on that side.

Make sure to only use copper based antiseize on the threads of those sensors. Silicone based will damage the sensor.

If the code is still on the driver side and harness is good, then look at your vacuum hoses. Make sure you don't have a broken or cracked vacuum hose somewhere.

 

WRAF? What's that? All the wiring for the oxygen sensor and vaccuum hoses are in good condition. Smoke test and examination of the wiring confirms that.

 

Wideband Ratio Air Fuel. Toyota's Acronym.

 

Haha I started thinking about it and figured it out afterwards, way afterwards but I digress...

What's the deal with URD's MAF extension plugs and the intake shield?

 

maybe you pulled a wire from it's seat in the plug. You'll need to pull the plug and do a thorough inspection to see if a terminal is backed out. If a terminal backs out of a plug it can make an intermittent connection and cause intermittent codes like you are having. If you didn't have the issue prior to messing with the harness I would highly suspect it being the issue. Most of the odd electrical problems and intermittent engine lights problems I see stem from someone causing the problem. Most times an incompetent tech other times a driver that thinks he can repair a vehicle. Good luck man . Next time a little trans fluid gets on the outside of a sensor it is no big deal. Hit it with some brake clean or starting fluid and leave it alone. If it ain't broke don't try and fix it. Oil actually protects, cleans and lubricates and normally causes no harm the external parts of a sensor.

 

Agreed do this... Swap sides for the oxygen sensors and see if the lean code follows the problematic sensor.

The issue i remember with the URD air intake was the MAF not sealing well on the tube. a lil extra o ring will solve that.

 

As I previously stated. There is no voltage dropout at any point from the sensor. I could just see where it raises up to 3.9V when at idle or low speeds when it should be at about 3.3-3.4V. I am now sure that the harness to the AFR sensor is in good shape and operating correctly.

The oil slowly made it's way up to the sensor over time. I had no way of knowing until later on by the time the sensor was damaged, as I had no idea there was that much residual ATF hidden inside the skid plate. I could physically see a difference between the contaminated sensor and the other ones. ATF got into the air sampling portion of the sensor body and got past the cotton filter element that is inside of it. It was and I know that, as I could see skewed readings from it.

The issue was present prior to the replacement of the sensor but the sensor itself was in poor condition and electrically it was shot. Also, oil is a poor conductor and will not allow electricity to flow correctly if there is enough on the plugs or the pins. So I would say no, oil on the sensor is not good news all around.

Why would a brand new sensor (replaced twice actually for the same issue just to make sure it was not defective) be failing? The sensor itself could not be problematic at this point, as it is in known new condition.

I would condemn the ring for the MAF but the smoke test shows that portion is actually sealed well.

 

Check if the terminals are female that one is not egged out and making poor contact. Also check that none of the male contacts are bent over from forcing the connection. May need an inspection mirror to check it.

 

That's not a bad idea. I can always tweak the pins a little bit from looking like this -- to this / (not as extreme but you get the idea) just to make sure there is a solid connection.

 

Fixed it! The MAF itself was messed up. Yes I tried cleaning the old one. Swapped it out and it actually cleared the check engine code itself after two running cycles and smoothed the idle out immediately after the swap out.

 

Blasted MAF's