air conditioning Lexus IS 300h Phase 3 Air Con (A/C) Pressure Sensor

[Zeb]

I've had my 2014 Lexus IS300h F Sport for around 3 Years. Never changed the Air Con gas. 

I switched the air con on just to see if it works as the days were getting warmer. It wasn't working and blowing warm air. As I have never re gassed the AC, i took it for a re charge and it failed. The charging machine came up with an error code B1423, which is generally associated with the AC pressure switch (located at the front of the car near the grill). 

I looked online for the genuine part (https://lexuspartsdirect.co.uk/product/lexus-is-phase-3-a-c-pressure-sensor/) and it was £300!! I went to a mechanic friend and he advised me that most Lexus/Toyota pressure sensors are the same and the error code could also be that the pressure isn't getting to the sensor in the first place, so it could well be the compressor. He advised to buy the same part on eBay for a tenth of the price:

 

 https://www.ebay.co.uk/itm/324187998809?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=4R6HUeZQQjG&sssrc=2349624&ssuid=rm8E24gDQZK&var=&widget_ver=artemis&media=MORE,

Same brand, same manufacturer of the "official" sensor. 

I replaced the pressure sensor, relatively easy to do but have to be careful when taking old one off as it could snap the base it screws on to. 

Re-gassed the air con and thankfully the car AC was working again. 

 

 

[royoftherovers]

5 minutes ago, Zeb said:

I've had my 2014 Lexus IS300h F Sport for around 3 Years. Never changed the Air Con gas. 

I switched the air con on just to see if it works as the days were getting warmer. It wasn't working and blowing warm air. As I have never re gassed the AC, i took it for a re charge and it failed. The charging machine came up with an error code B1423, which is generally associated with the AC pressure switch (located at the front of the car near the grill). 

I looked online for the genuine part (https://lexuspartsdirect.co.uk/product/lexus-is-phase-3-a-c-pressure-sensor/) and it was £300!! I went to a mechanic friend and he advised me that most Lexus/Toyota pressure sensors are the same and the error code could also be that the pressure isn't getting to the sensor in the first place, so it could well be the compressor. He advised to buy the same part on ebay for a tenth of the price:

 

 https://www.ebay.co.uk/itm/324187998809?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=4R6HUeZQQjG&sssrc=2349624&ssuid=rm8E24gDQZK&var=&widget_ver=artemis&media=MORE,

Same brand, same manufacturer of the "official" sensor. 

I replaced the pressure sensor, relatively easy to do but have to be careful when taking old one off as it could snap the base it screws on to. 

Re-gassed the air con and thankfully the car AC was working again. 

 

 

leave it on all of the time.

[Zeb]

12 minutes ago, royoftherovers said:

leave it on all of the time.

Hi John. I don't leave it on all the time as it consumes more fuel. Should I be leaving it on all the time? 

[royoftherovers]

Just now, Zeb said:

Hi John. I don't leave it on all the time as it consumes more fuel. Should I be leaving it on all the time? 

Certainly, both in my view and that of the original Honest John.

It has been on in my Merc for the past 19 years and the past 11 in my Lexus.Any increased fuel consumption consumed is negligble.

[Rabbers]

35 minutes ago, royoftherovers said:

leave it on all of the time.

I do that and, as far as I can tell, never had a problem because of it.  I used to wonder if I’m not using too much fuel but, according to the mechanic who handles air-con matters at my dealership, the increase is no more than 2%, probably less.  Of course, if fuel prices don’t go down any time soon, the difference will start adding up.

 

[Zeb]

20 minutes ago, royoftherovers said:

Certainly, both in my view and that of the original Honest John.

It has been on in my Merc for the past 19 years and the past 11 in my Lexus.Any increased fuel consumption consumed is negligble.

Thank for the advice guys. I have always been taught by elders is switch off the AC before you turn off the car as when you start it again, the load on the engine wouldn't be heavy with having to start the AC. I guess that was in earlier times and certainly my Lexus AC compressor isn't clutch driven so maybe i should leave it on all the time. 

[Herbie]

24 minutes ago, Zeb said:

Hi John. I don't leave it on all the time as it consumes more fuel. Should I be leaving it on all the time? 

The extra amount of money spent in fuel is minimal to say the least - hardly any difference at all.

However, the cost of not using the AC all the time, as you're beginning to see, can be high, if not very high.

Mixed in with the refrigerant gas is also a lubricating oil. This circulates around the system and keeps all the rubber seals moist and supple. Without that constant lubrication the seals can dry out and become brittle, which leads to leaks and faults. Aircon cools the car in summer; in winter it demists the screen in seconds; all year round it delivers clean, conditioned air that is better than 'standard' air for allergies or someone who suffers from asthma.

Your car probably also has Climate Control which is far superior to just aircon. All you do is to set the cabin temperature that you want, push the 'Auto' button and the CC will automatically do whatever it has to do in order to maintain that temperature for you.

When you regassed the system, are you sure that they used ND11 lubricating oil and not the PAG oil found in conventinal cars? The compressor is driven by a 500V 3-phase AC variable frequency motor and the windings of the motor are immersed in the oil for cooling purposes. ND11 does not conduct electricity but PAG oil does, and as little as 1% contamination by PAG will damage the motor windings.

[Herbie]

9 minutes ago, Zeb said:

Thank for the advice guys. I have always been taught by elders is switch off the AC before you turn off the car as when you start it again, the load on the engine wouldn't be heavy with having to start the AC. I guess that was in earlier times and certainly my Lexus AC compressor isn't clutch driven so maybe i should leave it on all the time. 

Hybrids don't have starter motors (or alternators) so even if that theory was true, it wouldn't apply here.

The 12V Battery boots the computers, charges the brakes and brings the hybrid system online, as evidenced by the READY light, at which point you can drive the car on Battery power. However, you'd only get a mile or so before the hybrid system needs the petrol engine to run and it does that by energising MG1 which spins the engine up to 1,000rpm before applying fuel and a spark to fire it.

This is one of the reasons why the 12V Battery in a hybrid is small. A conventional car with a starter motor will draw at east 300A to crank the engine, whereas a hybrid needs less than 20A to get the car into READY mode.

[royoftherovers]

7 minutes ago, Herbie said:

Hybrids don't have starter motors (or alternators) so even if that theory was true, it wouldn't apply here.

The 12V battery boots the computers, charges the brakes and brings the hybrid system online, as evidenced by the READY light, at which point you can drive the car on battery power. However, you'd only get a mile or so before the hybrid system needs the petrol engine to run and it does that by energising MG1 which spins the engine up to 1,000rpm before applying fuel and a spark to fire it.

This is one of the reasons why the 12V battery in a hybrid is small. A conventional car with a starter motor will draw at east 300A to crank the engine, whereas a hybrid needs less than 20A to get the car into READY mode.

2 more outstanding contributions Herbie, thank you very much.

[Zeb]

10 minutes ago, Herbie said:

The extra amount of money spent in fuel is minimal to say the least - hardly any difference at all.

However, the cost of not using the AC all the time, as you're beginning to see, can be high, if not very high.

Mixed in with the refrigerant gas is also a lubricating oil. This circulates around the system and keeps all the rubber seals moist and supple. Without that constant lubrication the seals can dry out and become brittle, which leads to leaks and faults. Aircon cools the car in summer; in winter it demists the screen in seconds; all year round it delivers clean, conditioned air that is better than 'standard' air for allergies or someone who suffers from asthma.

Your car probably also has Climate Control which is far superior to just aircon. All you do is to set the cabin temperature that you want, push the 'Auto' button and the CC will automatically do whatever it has to do in order to maintain that temperature for you.

When you regassed the system, are you sure that they used ND11 lubricating oil and not the PAG oil found in conventinal cars? The compressor is driven by a 500V 3-phase AC variable frequency motor and the windings of the motor are immersed in the oil for cooling purposes. ND11 does not conduct electricity but PAG oil does, and as little as 1% contamination by PAG will damage the motor windings.

Thanks for this, really appreciated. Just had a chat with the guys who regassed and they said it doesn't specifically state whether it's PAG or ND11, but it does say the oil is suiable for Hybrid & Electric vehicles. 

A bit concerned now about the potential damage to motor windings 😔

[Herbie]

21 minutes ago, Zeb said:

Thanks for this, really appreciated. Just had a chat with the guys who regassed and they said it doesn't specifically state whether it's PAG or ND11, but it does say the oil is suiable for Hybrid & Electric vehicles. 

A bit concerned now about the potential damage to motor windings 😔

As long as it specifies that it's suitable for hybrid and EV then you should be alright. The label in my engine bay says ND11 or equivalent so as long as it is equivalent you should be fine.

And I don't mean to frighten you but, if the wrong stuff ever was used, the entire AC system will need a thorough flushing out and the dryer may need to be replaced too because, as I mentioned above, even just one percent contamination of the oil by PAG has been shown to damage the motor windings.

The thing is, it may not happen immediately - it may take months to show up.

If you think of normal car wiring or even household wiring, the copper conductors are insulated with (most commonly) PVC, but in motor windings the insulation is an enamel coating and something in PAG oil attacks this coating, which in turn causes short circuits or shorted windings. Failure mode is usually that the damaged enamel coating allows 500V to track through the oil and to earth - in this case the car body - so the hybrid system shuts down to avoid electrocution.

Sorry Zeb, I really didn't mean to scare you but you may as well know. Of course, this is a 'worst-case' scenario and given that they reckon their oil says it's suitable for hybrids and EVs it should all be fine. Do they have a dedicated machine for hybrid/EV and one for conventional? If not, let's hope they thoroughly clean the one they have, to avoid cross-contamination.

[Zeb]

13 minutes ago, Herbie said:

As long as it specifies that it's suitable for hybrid and EV then you should be alright. The label in my engine bay says ND11 or equivalent so as long as it is equivalent you should be fine.

And I don't mean to frighten you but, if the wrong stuff ever was used, the entire AC system will need a thorough flushing out and the dryer may need to be replaced too because, as I mentioned above, even just one percent contamination of the oil by PAG has been shown to damage the motor windings.

The thing is, it may not happen immediately - it may take months to show up.

If you think of normal car wiring or even household wiring, the copper conductors are insulated with (most commonly) PVC, but in motor windings the insulation is an enamel coating and something in PAG oil attacks this coating, which in turn causes short circuits or shorted windings. Failure mode is usually that the damaged enamel coating allows 500V to track through the oil and to earth - in this case the car body - so the hybrid system shuts down to avoid electrocution.

Sorry Zeb, I really didn't mean to scare you but you may as well know. Of course, this is a 'worst-case' scenario and given that they reckon their oil says it's suitable for hybrids and EVs it should all be fine. Do they have a dedicated machine for hybrid/EV and one for conventional? If not, let's hope they thoroughly clean the one they have, to avoid cross-contamination.

Thanks for the information. It will be useful in the future and for anyone else whom refers to this thread. 

No, they don't have a dedicated machine for Hybrids & Electric vehicles so hope they thoroughly clean!! 

[Herbie]

7 minutes ago, Zeb said:

Thanks for the information. It will be useful in the future and for anyone else whom refers to this thread. 

No, they don't have a dedicated machine for Hybrids & Electric vehicles so hope they thoroughly clean!! 

Just one last thing - if the worst happens, I think the OBD fault code is P0AA6 if I remember correctly.

[Zeb]

17 minutes ago, Herbie said:

Just one last thing - if the worst happens, I think the OBD fault code is P0AA6 if I remember correctly.

Cheers, herbs. Much appreciated.