I bought my 2011 LS 460 new, been the only owner and driver (with rare exception to my wife for groceries, etc.). It has 120,000 miles. Never had a/c issues before this.

I've been battling my a/c for a few weeks now trying to fix the common problem many of you have had where it stays off for 30 sec to 1 min, then resets to 75°F after starting the car. This started just after I replaced the battery. I'm assuming that this experience is only due to trouble codes and changing the battery was coincidental.

** Not sure if it's relevant, but the old (dead) battery was a Lexus battery still under warranty that was changed a few years ago when another Lexus battery failed (also died under warranty). Instead of paying the dealer the same amount for a new battery at AutoZone (and risking the same 2-3 yr failure again), I just bought the AutoZone battery hoping it will last longer like all my other cars.

After this a/c issue popped up, I got TechStream with cable and checked codes. Initially, the code was B1441. I used the servo initialization function to no avail. Then bought an a/c amp from eBay based on other similar posts/suggestions. That didn't work either. Then finally found a video of someone running the initialization and showing the servos, particularly the Air Mix Passenger Side (B1441).


I was able to locate my servo and watch it during initialization. Seemed to work fine, but still a code. So I removed the servo, took it apart (careful to mark index on gear), did a little cleaning, re-installed and now strange things happening.

Initially, I got the same code. Then another code popped up, B1458 Air Outlet Passenger Front A/C Rear Air Flow. Then after another start, the B1441 code went away completely, but still the new B1458 code. So now I'm searching for this air outlet servo and can't locate it (see pics).

I found another post on a 2008 with heater problems with a great pic of the servos. The weird thing is I don't seem to have an air outlet passenger front a/c rear air flow servo (that I can tell anyway). At least the servo shown in the second pic is not on my car. I realize that these may be different models, but something still seems missing.

Any suggestions on how to clear the code? If I don't have the B1458 code servo, any ideas on how to fix this?



After disassembling/reassembling the air mix servo. The B1441 code disappeared after this pic.



This pic is from the other post about the 2008 heater problem, but illustrates the a/c well.



This is my car. Should I have a servo here?

 

The witch hunt for the naughty servo motor. Subbed for future knowledge and curiosity.
​​​​

 

Could you possibly have installed an ac amp that was for a car with the rear ac option? Maybe it is looking for hardware that is not installed.

 

The amp made no difference, so I returned it and reinstalled the original that came in the car. Current codes are with the original amp.

 

Could it be that the missing servo is for models with rear a/c control? Mine has no rear a/c control, only vents with manual open/close. Perhaps the "Air Outlet Passenger Front A/C Rear Air Flow" servo requires a controller that my vehicle doesn't have, so the servo is not needed. This still doesn't explain the code B1458.

Also, yesterday I drove it on the highway with a/c blowing, but noticed that the rear vents were blowing hot air (front maintaining 72°F in cabin). This would point to the "Air Mix Damper Servo Motor Circuit (Passenger side)" code B1441.

 

The thread pictures you referenced appear to be a LS600h. I think all of them have the rear ac option. Also it appears his LS600h is right hand drive. I have no idea if that makes a difference with the part pictured, just pointing it out.

I would surf the pictures on ebay from a Left hand drive, no rear ac option 460. Compare them to yours. Did the ac amp you removed have the exact same part number?

 

 

@miket000 , the new (actually used) amp model number is 88650-50B70 and mine is 88650-50B51. It was the closest I could find to mine and was hoping it would work. Anyway, the results were the same (i.e. still same B1441 code), so it made no difference. You're right, the pic is for 600h. The pic does appear to be the same orientation (i.e. heater core piped from passenger side, etc.) so seems to be oriented as is mine (even if it is RHD).

I investigated more and found that there is a servo on the driver side that is actuating the mystery lever arm in my last pic. Apparently there is a rod the reaches across the unit to the passenger side levers. I'm guessing that the housing is a common design for different models, perhaps explaining why mine doesn't have a servo on the right side (i.e. doesn't have independent control for rear mix).




Also, by removing the "Air Mix" servo indicated in the video and manually actuating the lever with my hand, it confirms that this control must be the Air Outlet for rear (open/close). Confirmation was made by feeling air flow from the rear registers when moving the lever with my hand. This means that TechStream must be opposite (i.e. Air Mix is really Air Outlet and vice versa) and the above pic is really the air mix. But I'm able to control it with TechStream, so not sure why there is still a code.

The other servo (air outlet), however doesn't respond to TechStream tests but does respond to TechStream servo initialization. Anyway, I bought another replacement servo. Will see if that works in about a week.

 

I kept tinkering with it. Guess persistence pays off. Now codes are clear and all working normal .

Here's a summary: all parts are originals, attempts to change amp made no difference so changed back to original, disassembled air mix servo and cleaned internals but no immediate success, disconnected and reconnected a few servos a few times, conducted tests on individual servos with TechStream to check response, ran servo initialization several times, ran a/c diagnostic (start holding auto/recirc, etc.) several times.

Today, all I did was disconnect the air mix servo, run the diagnostic a few times manually moving the mix lever to feel air from the rear registers (couldn't clearly determine how any of it was working/controlling by this, btw), reconnected the servo, ran the initialization and whammy! The code appeared as history only, not current. Cleared the code and now no codes and working on engine start as normal. Maybe there was just some debris in the ductwork/dampers that cleared .

Also btw, my comment about TechStream being opposite for air outlet / air mix surely a wrong conclusion. I tested it by manually adjusting the air mix lever several times and it seemed like it was adjusting hot/cold air and not open/close air flow, but still very difficult to tell since air flow to the back from the blower in the front through all the housing/ducting results in relatively low flow. So my test was not very accurate and certainly not conclusive.

 

Great stuff, persistence pays off.

 

Mjpsr11 nice job! If it starts acting up again you might look into the connector and wiring harness where the ac amp plugs in. Another member Unabee? Had some pins pull out of his ac amp connector which caused intermittent problems. He was able to fix / reseat the pins to resolve his issues.

 

@miket000 , great suggestion! I will definitely check that first thing if it happens again. For now, I'm leaving well-enough alone and happy its working again. I'll also have the spare servo I just ordered. At least I know how to tear this thing down quickly now!

Thanks!