b9boy

I'm starting to come around to your view sha4000.

Ive finally managed to find a version of Techstream that talks to my car successfully and it's saying there are no fault codes (or none that relate to the air con anyway). Surely if the servio's or AC amplifier were knackered Techstream would have found it?

I've also tried running extra tests on specific elements but there are so many options that after an hour I stopped trying.

If there is a specific one for the servos or amplifier and someone knows what they are called I will happily try again.

I presume this tells us nothing?

https://imgur.com/a/iVpDJqp


























I'm going to have the car booked in at the garage and ask them to flush the core.

One strange thing though is that every now and again the passenger side (the cold side) suddenly lets out a burst of cold air even though I've 1) got the fan speed on low, 2) directed the airflow towards the windscreen and 3) stuffed some socks in the vents under the glovebox. Does this again indicate a heater core thing perhaps??

sha4000

iTrader: (1)

Have you checked the temp of the inlet and outlet heater core hoses next to the battery? In the second to last pic I see the passenger side all the way to max hot but the passenger side duct temp is only 67 degrees. If you flush the heater core make sure he back flushes it also. If the heat comes back then you have found your problem. If so hopefully the heater core is salvageable. Mine was not I flushed it with CLR numerous times for 4-5 hours each time and I would always lose the heat on my drivers side/ your passenger side each time.

unabee

Ok, Now do the servo initialization-

Body Electrical / Air Conditioner / Utility / AC Servomotor Initialization

If that doesnt fix it, id say start digging in.

b9boy

Unabee - thanks very much for the heads up - i didnt know the Utility function was something to go into!

I've done what you said and I heard various movements behind the dash.

I then asked for Trouble Codes and got this:










Does this suggest a broken servo motor?

Incidentally I tried to check the heater pipes. I think they must be in a different place perhaps on a 600 to a 460 because I think this is them?









If so both left and right pipes were hot. If anything the passenger side was ever so slightly warmer but it was small degrees - plenty of heat in both!!

This morning I booked the car in (for next week) for the heater core to be flushed but wondering now whether that's worth doing?

p.s i really appreciate both of your help on this matter - top work !!!

unabee

Im glad it seems to be getting somewhere!
This is where a subscription to TIS tells you the next steps:

So running the calibration says complete or fails? You said it makes noises, but Techstream should tell you some info.

We also need to get eyes on the servo. The actuator linkage for the servo could be broken off or locked up. But you can run this test-

In the live data :HOT A/M Servo Targ PLS(P) Passenger side front A/C rear air flow air mix servo motor target pulse should be Min.: 0, Max.: 255 What is yours reading? Does it change at all with AC blend changes?

Im not sure if you can get under and see that linkage in the LS600. You might need to take the glovebox off. I dont have a photo of the dash internal layout for the 600.

Next step in the TIS for the LS460 is Wiring harness check which you state you have done somehow? Remember, I fixed my weird AC issue by simply taking it out f the AC ECU/ AC Amplifier gently pulling a little more wire from the harness and making sure there were no hard bends . Then cleaned (toothbrush and electrical contact cleaner) and reinstalled.)
if that doesnt fix it, REPLACE AC AMPLIFIER
if that doesnt fix it REPLACE AIR MIX SERVO MOTOR (for Passenger Side Front A/C Rear Air Flow)
If the Servo doesnt fix it, REPLACE AIR CONDITIONING HARNESS better pray that's not it, that would suck

sha4000

iTrader: (1)

Your heater core hoses are on the same side as mine it's just that your 12v battery seems to be on the left hand side where mine is on the right hand side. I get that same code now because I removed all the servos and did not put them back in the same position but it does not affect the heater in the front of the car. What it does affect is the AC coming out of the vents in back of the center console. I get warm air out of those vents instead of cold air but it does not bother me for now since everything in front is working properly. I've done the servo initialization plenty of times as well as run ALL the active tests to make sure each servo is working properly. I knew the heater core was plugged from day one but did not know how badly so I kept flushing it and was always getting lots of junk out of it because the previous owner put some kind of stop leak in there before he went to the dealer to get the radiator changed but the damage was already done. I got tired of the flushing and decided I would just change the heater core out in October before it got cold again. It was a safety issue since my drivers side/ your passenger side window would not defrost since there was no heat. This was not a Lexus issue it was a bad decision on the PO part for placing stop leak in the cooling system. I'm not saying this is your issue but it sounds exactly like what I went through.

I'm adding pics so you can get an ideal of where that servo is at behind the cover on the side of the center console. Top right in the first 2 pics and bottom left in the 3rd pic.

b9boy

Thanks unabee. I;ll check those items as soon as I'm back with the car. Out with my Land Rover Defender until later on Friday.

That last item sounds grim....

b9boy

Thanks for that info sha - I'll see if I can spot those servo's without removing much of the car.

That last pic though is probably the single scariest thing I've ever seen!!!!!!!! Under no circumstances am I doing that?! It'll get sold on at a loss before I entertain that mess!

sha4000

iTrader: (1)

If I were you I would still flush the heater core to eliminate it before running down a servo or AC amplifier issue. I could of fixed my issue from day 1. The tech at the dealership who I eventually developed a good repertoire did the flush flush on the selling dealers dime and showed me all the gunk. When I lost the heat again he checked out all the servos and told me they were all working fine. He also changed the water pump and flushed the whole system and told me it was definitely the heater core when that did not work. I could have just had them change the hater on the selling dealers dime but by that point I had already released them from liabilty since I believed that the issue had been resolved with after changing the water pump, thermostat and flushing the system. Even though the tech turned out to be pretty competent and I could tell that he felt bad when we first met he did most techs do. Change the easiest parts with the least amount of work and since they were in contact with the other Lexus dealer who basically said fix the problem and just bill us. So instead of doing the heater core which they quoted $1700 to do but would have been a much more difficult job he chose to change the water pump, thermostat and do multiple flushes which was a much easier job but paid the same amount of money.

I could of complained to the dealership but I chose to take the lose while learning a valuable lesson. I changed the core myself 2 years later and became a semi expert in the 460 HVAC system which is the biggest job I've ever done on any of my LS vehicles. Changing the cam seals on my 400 was more nerve wrecking but not as many things to pull off.

sha4000

iTrader: (1)

It does not work like that, you move the arrows up or down between 0-255 and watch to make sure the temperature changes with it. Sometimes the baseline is 90 so nothing happens until you get above that number. It also does not go to 255. It may max out at 186.

b9boy

HI - sorry for the delay but quick sit rep.
The garage flushed the heater core but said that "it was mint inside, like brand new". Nevertheless I now have heat on both sides of the car!!!!!...and all for the princely sum of £20.

Thank you very much for that advice. I'm not fully counting my chickens yet because Im aware that you had something similar sha4000, but lets see what happens - for now my Mrs will now passenger in the car so it;s a good result so far.

On a related note I had a mobile mechanic come out to look at one of my classics the other day and asked him to plug the car into his computer and it still showed a servo fault. It stated "B1458 Air Outlet Damper Control Servo Motor Circuit/Passenger Side Front A/C Rear Air Flow". Seems something is still not perfect but as I say at the basic level I have heat.

Thanks again for all the help.

sha4000

iTrader: (1)

I'm glad that you made some progress. If your passenger side gets cold again then IMO the core is definitely plugged. Did your guy backflush the core? Backflushing just means he would push the fluid out from the outlet pipe through the inlet pipe. He would have to repeat this procedure for several hours on really plugged core. I pushed ALL the coolant out of the core and poured straight CLR in and let it sit in there for 30-40 minutes. You have to be careful on how long you leave it in there because CLR WILL eat through aluminum. I tested by putting a piece of aluminum in a metal bowl and submerging it in CLR to see how long it took to start breaking down the aluminum.
I presently have codes 1457/1458 which are for both driver/passenger side servos but they don't affect the heat to the front. They just mess up the air mixture to the vents on the rear of the center console. You can change that servo if you want since it's easy to get to buy removing the glovebox and knee airbag on that side.

crazyb02

[QUOTE=sha4000;10719680]I hear you I felt the same way and I investigated this issue extensively for 2 years before I pulled my dash apart and changed the heater core which fixed the problem. I would flush the core and get some heat and then I would lose the heat again eventually. With Techstream you can test all the servos to see if they are operating. If you pull the glovebox on the passenger side a and the trim beneath the steering wheel you can see most of the servos in action. I even purchased a used AC amplifier off ebay to rule out mine and the problem still persisted
[/QUOTE

Is the AC amplifier pictured here? If so, where is it? I've been having the same 75 degree reset issue. Recirc door operates with no problem and when I removed the glove box, the servos I could see moved on command. I did get the 97 code when I ran the AC actuator check, but didn't see a clear reason for the code when looking through this thread. I also noticed my coolant was low when I checked. Thanks.

sha4000

iTrader: (1)

[QUOTE=crazyb02;10775597]The AC amplifier is on the side of the blower motor. You have to remove the glove box to see it. In the picture it has the number 32 on it. Code 1497/97 is a BUS IC communication problem and it says to check the wire harness or amplifier.

crazyb02

[QUOTE=sha4000;10776634]I take it, if it's the harness then that would be a P I A? The dash would need to be pulled?