Throwing multiple codes

Hi all, My check engine has been on and off for the last few weeks. So I decided to get a code reader. Looking to the community to help diagnose. From what I have read O2 sensors aren't as simple as replace and it's fixed. Tried to upload as many screenshots as I could. The third code was P0606 PCM I believe. The truck runs fine when the engine light is on or off. No issues starting, etc. Is it best to just go get the Denso O2 sensors and replace them all? I did spark plugs recently, yet I did not replace the injectors as they seemed to be in good condition. If there is any more information you all need, PLEASE let me know and I'll be happy to provide whatever I can, I'm a hair under 216,000 miles right now.

Thank you, Thank you, Thank you, for this great community!

 

Is P0606 and internal power failure of the PCM....is your Battery cables good and tight?

 

I'd guess the O2 sensor codes are real. I suspect replacing them might fix all of the non-ECM codes. Check back in if it doesn't. The ECM code is interesting. I'd start by resetting the ECM by disconnecting the battery for 15 minutes. Understand it will need to re-learn somethings after the reset so it might drive a little "off" for a day or two.

 

OK, so following up, how many O2 sensors? Denso part numbers and positions? Is there a helpful schematic from toyota to make sure they're installed in the right position?

 

Would the right parts include:

$131 Denso 234-9026 Air Fuel Sensor

Denso 234-9026 (quantity 2): Air/Fuel Ratio Sensor
Denso 234-4209 (quantity 2): O2 sensor Downstream

$47 Denso 234-4260 Oxygen Sensor

Denso 234-4260 (quantity 2): O2 sensor Downstream

 

I’m not sure why you would replace the A/F ratio sensors?
Your codes have nothing to do with those.

Your codes are for high voltage output of the O2 sensors during Active Air Control.
.059v is the threshold, anything more will throw a code.

Your scanner shows .650v for bank 1
And .955 for bank 2.

 

I wouldn't worry about the p0606 until you fix the O2 sensor codes as O2/AFR problems can cause that code to set.

In theory a skewed AFR sensor could cause the downstream sensor to read abnormally but a skewed AFR sensor can be hard to diagnose without a talipipe gas analyzer.
Fuel trims would be one thing you could look at and see if they are good as well as making sure all the sensors are capable of reading full rich/lean (which would be 100mv or less on the lean side and 900mv-1v on the rich side for the downstreams, I can't remember the actual range on the upstreams).

 

Might even start by giving the connectors a good cleaning and see if that changes your O2 sensor readings.

 

Yeah I had a P0138 if I remember correctly and I cleaned the terminals and put dielectric grease on them and it never came back. Probably been 80k miles ago at this point.

 

OK, so what is the best method to clean these before applying dielectric grease?

 

DeoxIT works well.

$18 Hosa D5S-6 CAIG DeoxIT 5% Spray Contact Cleaner, 5 oz.

https://www.amazon.com/gp/product/B00006LVEU/

 

I have the P0140 code pop up on my wife's 2017 Elantra...this after I replaced both with OEM Oxygen Sensors (Upper/Lower).

It's happened twice now where the check engine light comes on after about a week of her driving.

I figured it may be because I need to add anti-seize grease to one of the connectors going into the exhaust/catalytic converter area...one of them came pre-coated while the other didn't.

I'll have to try the DeoxIT...

 

So really the cause is an increase in resistance driving up readings in voltage. The high voltage throws the error code.

Causes: Corrosion, and DeoxIT would take care of resistance on the connectors and O2 sensors attached to them. If wiring is the issue, then new O2 sensors with clean plugs would lower resistance otherwise, correct?

Unless it's a matter of corroded wiring between the O2 sensor plug and the ECU, in which case in sure that's a bitch to trace back.

 

You got he jist of it.