riceman4k

Edit: I drive a 2022 NX350h

It's been a hot stretch recently and I noticed that my AC stops working when I'm driving in extremely low speeds/bumper to bumper traffic.
The car would mostly be running on battery and the AC stops blowing cold air. It doesn't matter what mode it's in, or how low I switch the temp to. I can manually switch the AC button on and it still doesn't blow cold air.
It also doesn't start blowing cold air once I start moving faster with the engine turned on.

I initially thought at first it was because the car is running on battery at low speeds, so it won't run the compressor. However the AC starts working just fine once I turn off the car and restart it, while also running on battery only.

Anyone else experience this? I'm taking my car in next week to get it checked out.

rogerh00

I experienced the same thing last week when I was caught in a bumper to bumper slow down on I75 in my NX350h. I was only able to go maybe 20 feet at a time at 5 mph for about 45 minutes. It was a 95*, sunny and no wind day. As soon as I slowed down I could feel the A/C start blowing warm air. No settings I tried helped. I can only guess when running on battery it can't keep up with the heat. There must be a solution to this. Is there a setting to run on gas engine only?

riceman4k

I initially thought too it was the battery not being able to keep up with the demands of the AC, but it was debunked by 2 things:
- The AC doesn't start to blow cold air again when I started to drive faster with the engine running
- The AC works perfectly fine after I pulled over and restarted the car. When it restarted, it was running on battery and the AC was very cold.

I'm beginning to suspect it's a programming/software issue. Probably worse than being a hardware issue as Lexus isn't really known for updating their software....

rogerh00

I saw just the opposite, when the traffic jam opened up and I was able to resume normal speed my A/C began to cool again. So who knows what the problem is. Maybe software as you say which could take forever, probably a new safety system 4.0. whenever.

I'm bummed out living here in Florida. I guess the word for now is not to buy a Lexus Hybrid in the South.

Droid13

Might be worth checking to verify that Eco A/C is not turned on (and the car is not in Eco drive mode either, which normally turns on the Eco A/C mode). I think this feature would reduce AC usage especially in situations where the battery is being heavily used like while stopped or creeping along. My two previous hybrids (while obviously being earlier gen with the NiMH batteries) they didn't have an A/C specific eco mode and when stopped or creeping along the AC would completely empty the traction battery in about 2 to 3 minutes (and that's here in Canada where when the temp reaches 85F - an early spring morning in Florida - the air raid sirens go off, everyone's phone is flashing "heat alerts", and we all have to hide in underground shelters to keep from melting, lol).

TheCDN

Looked through the manual, pg 35 notes:
Hybrid electric vehicle driving tips For economical and ecological driving, pay attention to the following points: ■ Using Eco mode When using Eco mode, the torque corresponding to the accelerator pedal depression amount can be generated more smoothly than it is in normal conditions. In addition, the operation of the air conditioning system (heating/cooling) will be minimized, improving the fuel economy. ■ Use of Hybrid System Indicator The Eco-friendly driving is possible by keeping the indicate of Hybrid System Indicator within Eco area. ■ Changing the shift position Shift the shift position to D when stopped at a traffic light, or driving in heavy traffic etc. Shift the shift position to P when parking. When using the N position, there is no positive effect on fuel consumption. In the N position, the gasoline engine operates but electricity cannot be generated. Also, when using the air conditioning system, etc., the hybrid battery (traction battery) power is consumed.

rogerh00

Thanks for the tip, I'll try it out. I think I was in eco mode. I drive almost all the time in that mode. It's 90* here as I type this at 11:30am

riceman4k

Some good tips there.
However I was driving in Normal mode and "eco AC/heat" was off.

Looking more and more like a software/programming issue now since the manual specifically says the traction battery will be consumed when the AC is used.
​

midcow3

@Droid13 I agree with you. Having had many Toyota/Lexus hybrids using the ECO mode seems to somewhat minimize AC, In really hot weather "Normal" mode is probably better for AC cooling.

YMMV,
MidCow3

NX450Guy

Did you have circulating air mode on, or were you drawing outside air into the cabin? Circulating air mode on might help.

Nevada

Check the wiring connector to the radiator fan motor, make sure it is properly connected.

Some of the service campaign software updates instruct the technician to disconnect the radiator fan before starting the software update, techs have been known to forget to reconnect the radiator fan motor after the update.