Trouble codes after AC diagnostic check? Whats next??

[daugherty83]

After having nothing but extremely hot heat all winter regardless of what temperature setting I used, I recently did the on board diagnostic check that is available if you have the digital heat/ac and came up with codes 21 and 41. The 21 code If I have read correctly can usually be disregarded due to the amount of light that is available when performing the check. The 41 code came up as well though and thanks to "TheDurk" I have came up with trouble areas that cause code 41. This is what the link he posted says for code 41.

Detection - Air mix control servomotor

Trouble areas -
Air mix control servomotor
Air mix damper position sensor
Harness or connector between air mix damper servomotor
and A/C control assembly
A/C control assembly

Anyone have an idea of what I need to be looking to replace. This is all new to me. Thanks in advance./

 

[TheDurk]

FSM--Code 41 Diagnostics

It's all right there in the FSM, Grasshopper. Intelligent diagnostics before parts swapping is theDurk's mantra. Obviously, the sensor or the servo are the prime suspects. (Saw your PM--rather keep it in the forum so others may benefit.)

The blue page number links should click through to other sections as needed.

 

[daugherty83]

Thanks Durk. I'm almost certain this is what it is, as I had the clicking early on in the problem. I found this link that was of interest with the clicking and the heat problems like mine. Grinding/clicking under dash - air mix servo - Toyota Nation Forum : Toyota Car and Truck Forums

Question is, will my toyota dealer have this part and what kind of $$$ it going to run me, haha.

 

[TheDurk]

Thanks Durk. I'm almost certain this is what it is, as I had the clicking early on in the problem. I found this link that was of interest with the clicking and the heat problems like mine. Grinding/clicking under dash - air mix servo - Toyota Nation Forum : Toyota Car and Truck Forums

Question is, will my toyota dealer have this part and what kind of $$$ it going to run me, haha.

He can get it. There are three servo's in the A/C system, and no easy way to tell which is which that I can see. You can probably match up the FSM to the on-line parts diagram to do it. They list for $150-$200 dealer MSRP and $112-$150 on-line plus shipping.

 

[TheDurk]

You should read THIS YT thread. especially the post at the end by NAT2500. Apparently, what happens there is a nylon gear in the servo that strips. If you get it out, you can rotate the gear 180° and the stripped part never engages. FREE FIX!!! Good luck. He also has the part number in there.

 

[daugherty83]

Thanks man, always a big help. Love the forums for this very reason

 

[daugherty83]

After pulling the servo from under the dash and connecting it back with the power plug while it is out, the arm moves freely 90 degrees or so when I turn the heat from hot to cold. I thought there would be some binding due to a stripped gear but it moves pretty good. I guess its possible that when it is under load and moving is when I get the binding. Stil clueless as to where to go from here though. I will try and take apart the servo and have a look inside. Arghhhh

 

[daugherty83]

Update *

I opened the servo up and did indeed find what I was looking for. The 25% of the gear that is used in operation has a good portion of it that is stripped away. I either need to order a new servo or turn the gear so I can use a good portion of it as only 25% of the gear is used in moving the arm 90 degrees. My question now is, what cause the gears to strip in the first place. Old age? Or could something need to be lubed somewhere along the line to help out. I'm thinking if a cable is dry somewhere and causing more load than normal on the arm, which would then cause more load on the gears causing them to strip. The truck does have 187,000 on it though, so I suppose it could be old age.

 

[TheDurk]

Good progress. I'd just lube up whatever you can get to, turn the gear, and hope for another 187,000. If you can find the bind, even better.

 

[daugherty83]

Yeah, I'm thinking about using some sort of thicker type lube other than WD40. Want something that I can apply and know it will stick around. Maybe a white lithium grease? I'm kind of unsure how to turn the gear though. It seems like it's pressed onto the metal shaft almost like a wheel bearing I guess.

 

[TheDurk]

I always use white lithium grease on plastic gears. Fishing reel grease is another candidate.

From NAT2500's post, it sounds like the shaft is squared or something so that you can slide it off and put it back 180° off from where it started. I'm just guessing, of course.