i'm hoping you guys can impart your 4runner knowledge on me.

I'm a honda/subaru guy and married into the toyota world. I've been chasing an CEL / VSC light for a while now.

I'll save the back story and just get to the point of this post:

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I finally broke down and took my wife's 4runner to the dealership after the CEL came back on after they replaced an 02 sensor to clear the CEL. - it worked for about 9 miles and came back on.

next code was for another 02 sensor, along with a lean code. They did a fuel injector service and said its running better. But they noticed "fluid" in the plug/wire harness of the 02 sensor.

differential fluid.

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SO i did a quick search when I got home and found these post:

http://www.justanswer.com/toyota/6xj...r-chronic.html

2003 Toyota 4Runner Transmission Leak into Electrical Harness (ECU) - Car Talk

http://www.justanswer.com/toyota/806...nner-took.html

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These post all reference transmission fluid wicking up the o2 sensor wires via the transmission wiring harness (toyota part number 82125-60310) all the way to the ECM.

This seems like a hoax…*has anyone heard of this or dealt with it first hand? If so did they replace the 82125-60310 harness and clean the oil out of the ECM?


Any insight or direction would be great. I don't plan on having the dealer do the harness…(I'll do it) unless you guys have a better idea…

help.

Eh, its not something I have seen on Toyota. BMWs and VW/Audi are a bit notorious for having coolant sensors become porous and wick coolant all the way through the harness and fill up the PCM. Honda also seemed to have a similar issue with their Radiator Temperature Sensors, but not exactly a common thing.

This would be the first time I have heard of a Toyota doing it though. Its a weird issue, but not entirely out of the realm of possibility as the way capillary action works it can put fluid in weird places.

All that being said, I don't see how differential fluid is getting in the O2 Harness, or how Transmission fluid is for that matter. I am assuming if they are finding fluid in the harness they are finding a sensor/switch/something that is leaking transmission fluid?

BlackWorksInc thanks for the response.

I plan on seeing the car tomorrow, to actually assess for myself where fluid may be coming form. My contact at the dealership said there was a service bulletin for this issue…*but i couldn't find one online.

Hopefully when I talk to the service manager tomorrow, I can get some real answers.

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IF fluid is wicking out as they suggest, wouldn't a simple splice in the wire stop this fluid from moving up the wire - essentially breaking the path its flowing?

Obviously it sounds like to me. Let's throw parts at the truck and guess what is going on. It's not my money. Lol. I would scan the truck get the codes and fix it myself. The price you paid for the services that were just performed at the dealership, you could have bought all 4 new sensors and fixed your truck. Unless there is more to the story that we don't know about

I agree Gshadow, having the dealer change an 02 sensor isn't the most cost effective. I was hoping they would know something I didn't, as I've been chasing this issue for a while.

The "fluid" is a new variable I hadn't seen yet. but here's a basic run down of the car history concerning this issue.

brief history

• 115,xxx CEL comes on
• ◦ *Adv. Auto reads code for driver side lower bank o2 sensor. I changed both lower 02 sensors (passenger side should still be good)
• • CEL goes away
  
  116,xxx prepping for long road trip I change*
• ◦ front rotors
• ◦ front pads
• ◦ spark plugs
• ◦ air filter
• ◦ new brake fluid
  
  117,xxx VSC/ABS/brake lights come on along with VSC alarm
• ◦ no power assist
• ◦ no rear brakes
• • Took to shop A; said wheel sensor and ABS pump motor were bad
• ◦ I replaced wheel sensor (ABS - passenger front)
• ◦ changed 40amp and 50amp fuse for ABS
• ◦ replace gas cap
• ◦ checked what I could
• ◦ tried to reset VCS
• ◦ no stored codes in ECU
• ◦ they ordered an ABS pump motor, but it didn't help? returned part ($1,400)
• • Took to shop B;
• ◦ replaces electric ABS pump (used unit)- re-bled brakes - issue corrected.
  
  120,850 vsc light, CEL, ABS light all come on, no alarm this time.
• ⁃ 10/09/12 Took to Hendricks Toyota to read code
• ⁃ I replaced O2 sensor with factory toyota piece. (B2S2)
• ⁃ CEL cleared
  
  123,689 new Alternator, acc. belt, water pump, tensioners and pulleys for drive belt
  
  129,130 CEL, VSC trac, VSC off light all light up
• ⁃ dealer replace 02 sensor (b2s1), cleared light
• ⁃ I did power steering flush
  
  138,734 CEL, VSC lights > took back to dealership
• ⁃ dealer replaced (b2s2), CEL cleared, but came back on in 5 miles
• ⁃ dealer did fuel injector service
• ⁃ dealer pulls code for another 02 sensor, decided this is odd and looks further into the issue and finds fluid in harness…*
  
  
  7/19/14 this is where I’m at today.
• ⁃ I have parts to replace rear rotors/pads and driver side CV (just waiting to get car back)

brake booster bad could very well be a improper brake bleeding. there is a proper procedure to do this that requires use of a techstream or there is a manual way to do it properly or else you will mess up the brake booster.

FYI any cel will trigger abs and tracs lights you get one light you get all 3 every time.

once one o2 ges bad, you can expect the others to follow soon after. my school of thought is, bite the bullet and change them all at the same time. this way its less headache chasing something.

i would goto rock auto.com and buy denso oem sensors for the other side. change out what was never swapped out. call it a day. this bullshit about it being lean and stuff like that. i belive the sensors are failing.

as for the fluid, i would use some brake cleaner and spray the crap out of the area and clean it off and put in a new sensor.

your t4r is a baby, mine has 184k and runs like a champ so dont give up on it jsut yet.

good luck

I have been down the O2 sensor replacement road before. Before doing anyone of this check over the vacuum system for leaks and more importantly in a lean condition give the mass airflow sensor a good clean with MAF cleaning solution. I changed out 1 sensor only to have different codes appear. Swapped the B1 and B2 S2 and the alarms didn't change sides. Proving sensors were fine. Funny thing was it was only showing lean on the first bank using a live data scanner. Two Philips screws, and a 15 second shot of MAF cleaning solution and my truck runs like new 7800 km later no more lights and better fuel mileage.

You cannot rely soley on CEL codes to trouble shoot these problems. The factory service manual will tell you all the items to check if you have a specific CEL code and often times it is not as simple as the part that is throwing the code.

This statement is very true. You want to remember that the DTC (Diagnostic Trouble Code) is what the vehicle THINKS is wrong, that doesn't always mean that's what is wrong with the vehicle.

You should always approach a vehicle assuming "the little dude in the dash" is lying to you, until you've proven that he's not.

had a short call today with the dealer.

Im slated to have another call with tomorrow with:
the service manager
the tech who's been working on the car
my service contact

This was at their request.

At this point I just want the car back, as I feel I can do a better job of working through the issues. (i have a feeling Toyota just changes what the computer says to change.)

The MAF cleaner is a great idea, I haven't done that since I've been involved with the car (since 75,000)

between that and changing any 02 sensors that are still original should get me in a better place.

the whole fluid in the harness will require a bit more investigative work.

I'll keep you guys updated, but thanks for the help. It give me hope that I can run the 4runner for another 5 years. (hopefully more!)

For what it's worth, after I bought our 2004 my Toyota tech told me about this. He was stating how these cars are very reliable outside of the few instances of head gaskets leaking and this transmission fluid wicking instances. I had never heard of it before and never after, until now.

You can definitely drive it for more than 20 years. I had my car new, V6, 2005 SR5 model and now, I have around 100000 miles. I'm looking forward to drive it as long as possible. it's good not to have a car payment and enjoy my spending with other toys.

A couple of things I do since I'm in the rust belt area, when maintaining my car and I see rust, I paint it rightaway with any rust converter like this. Krud Kutter 32-oz. Rustex-Rust Converter-RX32/6 at The Home Depot. A small thing you can do can go a long way.

By the way, I do all the maintenance myself like oil change, transmission oil change, power steering oil, radiator change due to leaking (done just this spring), differential oil, PCV valve (done this summer), rotor and brake pads, brake fluid flush, tire rotation, rear shocks, drive belt(still good but i have to since I will be going for a long drive), alternator(failed around 85000 miles), new tire last year (first time).

On highway driving, i get around 19-20 mpg. i'm still wondering on how to replace the Oxygen sensors since it's too tight in there to use a wrench.

In comparison with my wife's car, i spent so much less with the maintenance of this car.

Well i had a short call today with just my service contact.

Basically they refunded the money for the first 02 sensor, and I took the car home. (I didn't want to pay $2,500 for a new wire harness/ECM)

This is what my report said:

Engine light cam back on P0136 and P0171. B1S2 malfunction and B1 lean condition. 02 and A/F sensors are reactionary and can be active test driven up and down. but not evenly. B1 is slightly skewed lean. Found fuel pressure reg hose off of intake manifold. Reattached and test drove again. B1 still lean, but LT fuel trim came down slightly. Unable to identify any false air entry (unmetered). Ran injector cleaner through hoping to clear restricted injector(s). Fuel trim improved slightly but B1 still lean. Eventually found that ATF has wicked through the engine/trans harness from the trans solenoid harness. ATF has made it through the harness all the way to the ECM. Gave estimate for ATM solenoid harness, Egine/ECM harness and ECM.

I performed a MAF cleaning tonight. (car idles good - no CEL)
I looked at the ECM plug for "fluid" content

Is the trans solenoid harness the part number listed above? 82125-60310

Here are some pics. Would you guys recommend that I pull the trans pan off and replace the harness?

ABS module:


ABS plug


ABS module wiring


fluid on paper towel, after I wiped it all down.


second plug form the top on the main ECM


third plug from the top on main ECM

wait what?

where are these pictures coming from?

inside the car?

is this the passenger side under the glovebox?

is it oil? or soda coffee drinks or whatever...???

i would open that box these connectors were connected to and look inside and clean everything out! there is some sort of electrical spray that dries fast and non conductive.

this is a awesome find! i thinking something spilled or something leaking in somewhere

these pictures are from inside the cabin. under the glove box. both the ABS module (smaller looking ECM) and the main ECM.

I appears to be an oil/ATF type of liquid as mentioned by the dealership

is removing the ECM simple? it looks tucked up there pretty tight.

look like you found what is causing all those. clean all those electrical connector with a electrical contact cleaner and see what happens.