L S 430 A/c Fault Codes

Loathecliff · May 13, 2015

Before rushing to ATS with my Groupon voucher, I thought I'd try the 'hold recirc & auto buttons, turn on ign & let it beep' on-board fault code method, (plaudits to him responsible for posting that one :0 ). I know that's for the 400 but I thought it was worth a try, & it produced lucky nos 23 & 28, (& I felt quite pleased with myself for a techno-resisting old-skool diesel man).

I'm guessing one is the solar sensor complaining about UK weather, & t'other most likely is pressure? But who knows for sure? These aren't obd kind of nos, & thus techno-resistance mode engages again - HELP, please!!! :0)

Beejay55 · May 15, 2015

I did the same test and got the same codes. Can anyone advise what they mean, please?

ambermarine · May 16, 2015

Hi

On the LS400 the 23 code means pressure sensor circuit which usually means there is not enough gas in the system, as far as I can tell there is no code 28 but that number could have replaced the solar switch circuit which is 21 on the LS400 .Run the diagnostic test again and check if it shows a 21 code on its analysis list.

Suprazed · May 16, 2015

Hello, just joined after scouring the net for exactly the same problem.

I've bought a 2001 LS430 a couple of weeks ago for a stag trip down to Monaco.

Car drives beautifully and will be very comfortable for the 2000+ miles thatnits about to cover next week, all electrics function except for air con.

When i switch on the ac and set to cold it doesn't seem to engage/click, the compressor can easily be turned by hand in either direction and I just had it regarded last week which showed that it was holding pressure.

I ran the diagnostic procedure and got the error codes 23 and 28.

23 relates to the pressure switch which is just at the front next to the filling point and easily accessible, I'm just not sure what 2 connection need to be bridged of the 3 that are available as this seems to be common culprit.

Any further advice would be very welcome.

Thanks in advance

Loathecliff · May 16, 2015

Can confirm 28 is the solar sensor as the code didn't appear in bright light.

The very obliging guys at ATS Liskeard did the decent thing & insisted on a long pressure test for free, which the car unsurprisingly failed.

(The hardest part was getting the Groupon refund via their suddenly awkward software).

Mildly off-topic: As the vent output was a tad feeble I took out the pollen filter & tried the fan without it. I could comb my hair with the blast.

The filter was black so I decided to wash it expecting a soggy mess. It survived.

Reinstalled after drying & the hair drying gale was still there! :)

Zia, is it possible if showing a code 23 that the software will prevent the compressor from engaging?

Suprazed · May 19, 2015

Loathecliff, regarding your last point, yes it's quite possible. Since posting I have acquired the ac fault finding procedures. The pressure switch seems to be registering a healthy voltage which suggests the pressure in the syst is perfectly fine and I've tested the ac relay which is also fine.

What I'd like to do next is supply 12v directly to the compressor to see if it runs. There's 2 connector plugs on top of the compressor, can anyone advise which pin under which connector I should supply 12v to so that I can eliminate the compressor (or not as the case at be)?

TIA