ex00

2018 IS300

Hey everyone, I guess I'm having that HVAC issue that these cars are plagued with. Before I take it to the dealership and get charged a diagnostics fee, trying to utilize everything before going that route and getting robbed. Wanted to try see what other methods I can try for now.

What I have tried so far:

• Unplug the fan relay fuse for a few minutes before plugging it back in
• Disconnected the negative battery terminal for 10 minutes to try get it to initialize (didn't seem to do anything, assuming I was suppose to see something on the screen showing the initialization).
  • This helped a little bit on the side that was blowing warm, but still noticeably warm if you put your hands by the vent
• Checked for any leaks
• Checked the cabin filter to see if it needed to be changed
• Tried to mess around with recirculating, dual zone, auto temperature mode and etc...

Update:

• Was able to initialize the servos using a scan tool without success but the warm sides are blowing somewhat cold air but not at optimal output
• Multiple DTCs but waiting for a weeks worth of starting the car to see if any will show up to narrow down on the DTC for the specific servo. It seems like it's a blend motor.

martelito0

Been having the same issue for little over a year I talked to my local Lexus dealer he’s got multiple cars lined up waiting for ac servo replacement there’s a recall on the 2016 model but they told me to call corporate to file a case and they acknowledged the problem but they don’t want to release a recall for it such bs no way bro but to pay outta pocket for the reprogram and greasing or full replacement

ex00

Is there a number or email I can contact about this? Pretty much out of the standard warranty period and I don't think anyone should be paying any cost of fixing HVAC issues on a car like this. Especially when those parts are prone to failure at anytime.

martelito0

+1 (800) 255-3987 I called they didn’t want to help me since I was out of warranty too but they know it’s a issue on these cars but won’t file a recall was really upset ig they need more people to complain

ex00

I realized that reroutes to your local corporate Lexus which in this case the dealership I do not trust after politely asking them about the TSB and brushing it off as another way to make money off people. Going to be waiting a bit to see if I can get the HVAC to generate actual DTCs that I need since I had a bunch and I have a feeling that some might be from a previous instance that I was acting up a few months before. Just bought a Techstream cable and have everything else lined up so I can keep initializing the HVAC and see if it goes since some people have mentioned it took several tries. I just can't see myself replacing all the servos and amplifier and trying to get the flash file for the amplifier.

ex00

Does anyone happen to have the the calibration files available? Looking to taking a shot at flashing the amplifier module.
Looking for Calibration ID file: 886505387001

Since the passenger side the the area of the issues, took out the glove compartment and looked at what I could given the tight clearance of everything. I know the servo for recirc and fresh air works and also inspecting the blower motor with the cabin filter out. Checked all the harnesses around the area and everything seems to be in place, I was able to get air out of the passenger vent until assembling the glove box back it was back to square one. Any idea how to remove all 3 servos without an entire dash removal? Thinking of just replacing the servos once I can pull DTCs again to see which ones are the actual cause. My hard guess would be the blender motor being the root cause.

Additional troubleshooting I've done after reading a bit more about things to check for:

• Tested battery which came out to a bit above 12V
• Tested alternator via battery after starting the car and received a bit above 13.5V. From what I understand and have read that the alternators on the 3IS isn't a high output so it will only charge up to ~13.5V and never over 14V as some other cars do.
• "Reset" infotainment which didn't do anything but restarted the infotainment system
• Tried to get the passenger side servos back in sync. Activated dual mode and cranked up the temperature to max heat on the passenger side. I was able to hear the servos move which is a good thing. Kept playing around with the temperature thinking I can get the servos back into place.
• Tried to get the servos into sync without dual mode. Strange thing is that going from LOW to ~63F the passenger side starts blowing hot air.

zhifan1

Video below seems to show the tech replacing the servo motor without removing the entire dash. Also, AFAIK, the blender motor that causes this uneven air temperature is 87106-30500, if change the mode to heat and then change it back to cold air, this blender motor refuses to budge, causing the uneven temperature. I'm having the exact same issue, but re-initializing the servo motor using Techstream seemed to work for me, so now i'm cautious to use the heat and normally I do not need it, but had when changing coolant.

ex00

So it looks like just removing the bottom covers under the steering wheel and you have somewhat access to all servos on the drivers side? Assuming the top servo is also accessible that route as well.

My question would be what other servos I'll need to replace for vent control for the right vents. The far right vent isn't outputting any air at all no matter how high the fans blow. If I switch to just cooling at the feet it's working fine with air flow. When I switch to windshield, drivers side is cold but the passenger side is blowing hot.

Even then I still don't have a solution for the passenger side replacement, I was thinking of removing the blower fan assembly to make the clearance needed.

ex00

Just an update. After searching for information on how to remove the blower assembly I was able to find the repair manual for the 3IS models and after going through several short documents. The cars comes onboard with a diagnostics function without having to have a scan tool or Techstream for that nature to pull DTCs.
To perform this:

1. Press the start button without your foot on the brake to put the car into IGNITION mode
2. Quickly hold down simultaneously hold AUTO and RECIRC buttons within 5 seconds of putting the car into IGNITION mode
3. All the AC control lights will flash and when the diagnostics is complete, it will display a 2 digit number on the display panel which will say DIAGNOSTICS XX or the AC panel which will have a 2 digit number only. Press the TEMP UP button for the drivers side to scroll through additional DTCs if there are any present
4. Once you have noted down the DTCs you may exit by pressing the OFF button on the AC controls

Basically the 2 digit DTC number(s) you pull corresponds to a B14XX number which will help you determine the servo(s) you will need to troubleshoot or replace.
Luckily for me it was DIAGNOSTICS 54 meaning B1454, Passenger Lower Servo. This will be part number 87106-30550 for Damper No.4. Hopefully this helps someone who wants to go about replacing them on their own and doesn't want to buy Techstream or a $100+ scanner tool. You still need to be able to reinitialize the system going this route and there isn't a way to do that without either.

ex00

Just a final update. Part arrived but realized Lexus went a little stupid in designing the AC system. The AC piping coming from the engine bay are in the way so there is no way to access the lower passenger blend servo unless you have a phillips rachet that is small and thin enough to fit in about a 1-2cm clearance.

I was able to reinitialize the system using techstream after several tries I have full AC again. Will post up a notion guide on Techstream for everyone.

zhifan1

Hi mate... guide for resetting on TS? Thanks much..

ex00

You can find the guide here