miket000

My 07 460 base had a similar issue. Only cold air out the passenger side. Drivers side had no air flow. It also reset to 75 degrees on engine start up after about 1 minute. I replaced my ac amplifier with a used one for $40, problem fixed. I'm guessing it was a pin issue after reading a few of these posts, interesting.

unabee

@miket000 it could very well have been your amplifier. Maybe my situation was unusual?

​​​​​​Do you recall your AC Amp wiring harness being very tightly pulled?

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miket000

Unabee I tried to take as little apart as possible to reach it. I only remember it being a tight fit to swap it out. You must have taken more apart than I did to check pins. If I had to guess I would say my harness had some slack, maybe an inch or so.

If my car's ac system was working correctly when the car started it continued to function correctly until I shut the car off. The ac system started acting up 1 month before I decided to replace the amplifier. My temporary fix during that month was to restart the car if the ac failed to operate correctly. It progressively got worse, almost every start or restart resulted in the ac temp resetting to 75 followed by random ac faults. Sometimes it would only blow cold out the lower vents. Sometimes only the passenger side. It was 115f during the summer here when it started acting up. How did you know which pins to check? I'm fighting a random power steering voltage fault on my car too. I ordered an oscilloscope to help narrow that fault down. Having a wire schematic for the steering ecu module would be helpful. I suspect the second power steering ecu I replaced is faulty too. Seems unlikely though.

b9boy

OK, so I've found the AC amplifier underneath the glovebox and undid the 3 connectors. All seemed fine in there (no loose pins or anything), but fairly sure you cant tell a knackered one from just looking at it of course ha ha.

There was no slack in my harness at all. I tried to pull gently but it wasnt for moving so i blew a few leaves out that were down there, blew on the pins and connected everything up. It still blows cold.

To answer an earlier question my A/C light comes on when its asked to and stays on. the car starts on whatever temperature I last left it at i.e it doesnt default to 75 degrees (or the Celcius equivalent I use instead).

I dont have techstream currently but I do have a Foxwell NT510 bought for my BMW's so I'll have a look today at how to get the Lexus software on it and see if it tells me anything.

p.s I did go into the hidden menus kindly posted up earlier via You Tube video and tried to clear whatever codes were in there but they only seemed to relate to the sound system (which works fine as far as I can tell), and couldnt see anything relating to the air con system...?

Perhaps its worth my buying a new amplifier although surely that would show up as a faulty part on Techstream/Fowell diagnostics wouldnt it??

jdanielca

yes you can get various codes readers a ELM327 wifi device plus carista app will read codes... blue driver or whatever that is will also read codes. and you dont have to get a new one, just a used one with some sort of warranty.

b9boy

Thanks for digging for that. As I read that document it leaves us non the wiser - or am I missing something?

I know the refrigerant level is fine, and I know half of the car does exactly what it's told. I know my cabin filter door/lid flaps around and that using the recirculation function doesnt make any difference. I also know that unpplugging the AC amplifier and putting the connectors back hasnt fixed it.

unabee

@b9boy Actually, that Prius document tells us a lot. It mainly tells us that your system is very different than the LS460 that we are used to. I don't mean to be condescending or rude, but helpful- If that document doesn't point you in the some direction, you should probably be seeking professional help with this repair. You need these kinds of documents to start drilling down the small systems and then actually locating the fault. This is the top of the mountain and you have to climb down by using that as a map. Although a 600hL specific map may be a little more helpful if you or someone can get TIS access to the 600hL AC system docs. This Prius doc might not list all the spots to check in the 600hL system.

BUT!! Even if you do decide to proceed, You might have to seek a hybrid tech anyway. You have some potentially expensive repairs, and there are a few of those parts that run on a very dangerous high voltage drive battery. You can kill yourself with one of those batteries if you touch the two poles of the battery (~400V DC if I'm not mistaken)

But lets rule out some simple things first-

• Refrigerant volume- your shop checked it? How? Double check it in the sight glass (I don't know where that is on a 600hl). If they did a manifold pressure test, then that should be ok if they gave you the numbers. Fingers crossed they didn't do it right (they're human) as refilling your system would be the cheapest way out at this point.
• Compressor/inverter/cooling fan - Does the "cold" air you feel seem to be affected by the AC system, or is it just cold outside air you feel? Does it blow at speed or just kinda drift in? If it blows actually AC chilled air, you can 90% rule out these 3 parts. Generally if the AC inverter goes it takes out fuses with it. they're big sand-filled fuses though, and they're on the HV system. You probably don't want to be poking about at them unless you're familiar with how to be safe around high voltage DC. I say 90% because it still could be a communication error caused by a fault in one of these components.
• To test the CAN communication, you can make sure all the connectors are secured., but don't touch the big gauge cable connections with the orange wires, those are HV. If you really want to watch the CAN communication, you will need techstream or a wiring diagram and an oscilloscope or datalogger (you'd already own and know to use them if you were going to go this route). it could still theoretically be the AC amplifier, but I think you'd be getting different codes and the AC off behavior. Your system is different than ours in many ways, so you need to get more info on this system before we can dig in more deeply into the issues. I'm going to be honest,This would probably also be best left in an experienced electronics techs hands. Not a one-off shop, maybe someone that specializes in electronics or hybrids. Your average shop mechanic is going to just start replacing stuff and sending you the bill, an electronics tech will be able to drill-down a little before forcing you to pay a bill full of guesswork.

Let us know what you find with the sight glass and AC blower/temperature change. If that doesn't work, I'm out of Ideas until we can see techstream data or the 600hL system diagrams.

sha4000

iTrader: (1)

This is a problem in itself but I don't know that it would temps. I've read around the forums where low refrigerant as well as low coolant caused temp issues in cars. Also this sounds like an issue that I just resolved. Take the temperature of the heater core hoses to see if the inlet and out hoses are around the same temperarure.

b9boy

Thanks - I'll try that. I assume they are under the bonnet yeah? I'll get digging.

In the meanwhile to answer the other questions:
- the garage told me they recovered a full 850grams of refrigerant, the system held pressure (no leaks) and it took 850 back again. Is that the correct level?
- whilst the air on the passenger side is cold, it is even colder with the A/C on and set low.
- the air coming in on the passenger side is affected by the fan, so it comes in at whatever fan setting you ask it to...it's just constantly cold

Can I ask (without sounding at all challenging) why we dont think it's the A/C amplifier, or a blend door issue? Ive done lots of previous reading up and nearly all cases of 'cold on one side' tend to be low refrigerant, blend door, servo motor or A/C amplifier. I accept my 600 might be slgithly different to a 460 but you'd expect similar issues? I'm not getting lots of codes from the simple diagnopstic test that others havent seen?

miket000

Since you know something is wrong with the air filter door I would try to fix that first. Assuming it is the same as an ls460 you should be able to hook the linkage back up. There are a few tutorials on here. The position of the door itself shouldn't affect the cold vs hot. However the motor that drives it open or closed can get jammed by the linkage. The motor getting jammed between open and closed could cause some confusion in the system. I think I read on another thread there is some sort of rotary encoder in the motor mechanism that relays the position of the air filter door to the ac amplifier. The system is more complicated than the motor just driving the door for a few seconds open or closed.

I doubt it is an issue with the ac amplifier simply because in most cases I've read the ac temp resets to 75 on startup. On engine start the ac also has a delay of about 1 minute before anything happens.

sha4000

iTrader: (1)

It could be the AC amplifier or one of the servos that control the blend doors but until we know for sure what codes 75/76 mean we can't be sure.

unabee

850 is probably right, a base LS460 is 600+50, so that's within reason having an L.

So you've determined the AC is working (and therefore the inverter is working), the blower works and the refrigerant level is good according to the report. All that's left is CAN bus. Except, the LS runs the AC on a LIN bus, which is like a proprietary sub-system on the CAN bus. I doubt it would throw a CAN failure with one system on a LIN bus misbehaving. We really need the manual here to verify these codes/failures.

Assuming they mean the LIN, That could be anything. a loose wire, the front control panel, a servo is messing up a sensor, a sensor is messing up a servo, AC amplifier in a different failure mode than we're familiar with... has anyone been working on this car? Have you looked at the records? Does Lexus in your country record service info (in the US you can look this up at https://drivers.lexus.com/lexusdrivers/history ). Just to see if someone has been poking around previously. its always good to check where the last guy worked on the car .

My plan of attack would be to get a Techstream cable, do a DTC reset and then a servo recalibration. Once you've run it, see if it gives you a communication failure still or it wakes up (temporarily or permanently) .
Then sign up for TIS and get the manual for this thing and run techstream in realtime and see what is what.
We need a deeper view at this point.

b9boy

Thank- I'll have a look at the tutorials because at this stage I havent got the glovebox stripped down beyond removing the small hatch that covers the filter area.



I'll do some more digging on the codes then...


I'll pick up a Techstream cable because Im having problems with Foxwell on downloading Lexus software t my handheld unit. Their website is totally sh17e !!

p.s what is "TIS" Toyota something Support?

b9boy

OK - found out what TIS is.

I've been on the website and it wants $20 for 2 day access to the site. I presume this site will allow me to download a manual or something for my car will it?

There is a big warning flashing up saying the site is only for cars sold in Northern America - was the LS600hl sold over the pond guys? I assume it was but just checking before I try and buy something I cant use...

I've also done the '11 actuator diagnostic check' where the air con system one by one activates each servo. It appears to be activating them correctly and there are no audible warning buzzers as it goes through each step...?

edit: Wiki says the 600 was sold in the US too so I'll go and order access to the TIS website. Given I will only have it for 2 days can someone tell me exactly what resources I should be dpwnloading from there to get maximum benefit both now, and likely things for the future?

Also if anyone else wants anything downloading just let me know and ill add it to the list!!

Thanks

miket000

If you google techstream on ebay for about $20 you get the software and cable. At least that's how I installed mine. There are no recurrent payments to make. Once installed it works whenever you need it.