W140 air con

[grober]

maybe this might help? its for the later unit?

A/C Air Conditioner Diagnostics with trouble codes list, Reset, Sensor Data – MB Medic

www.mercedesmedic.com

 

[BlackC55]

Replacing seals is easy enough. Undoing the pipes can be the tricky bit. They do tend to seize up on older cars and often the pipes are NLA.

 

[alabbasi]

Here you go: Automatic Climate Control Diagnostic Trouble Code (DTC) Memory

 

[alabbasi]

??

K6JRF Auto Page

FYI, I remember thing guy from the Mercedesshop forums back in the early 2000's. He was super knowledgeable and helped a lot of people. It was a huge loss to the community when he passed..

 

[219]

Thanks all - I'll try these things and report back

 

[219]

Here you go: Automatic Climate Control Diagnostic Trouble Code (DTC) Memory

Brilliant - sorted now .

I followed the instructions on the Benzworld page - got in to read the codes - only two were stored : Eb1 234 - sun sensor , and Eb1 241 - refrigerant fill ; I then cleared these codes , checked again that none were showing .

When I restarted the car , AC working correctly , no need to hold the button down ( not that it was a great hardship ) .

One query : the 'sun sensor' Is that the sensor behind the interior mirror which also controls the auto wipers ? Or is it the sensor on top of the dash ( which I'd previously thought was an IR pickup for the remote key fob ; am I right in understanding the remote fob is both IR and RF for different aspects ? ) .

When I first got the car the wipers would only run on the two constant speeds , and after reading up I disconnected the sensor behind the mirror , which then gave me manually activated intermittent wipe as well as the two constant speeds ( all I'd ever had on my previous cars ) I know the windscreen has been replaced at some point since , despite being Sigla branded like all the other glass it does not have the MB logo ; so I guess an OEM , but non Mercedes replacement .

All the double glazed side windows have this etching , Siglaplus , with the MB logo



The rear window has slightly different etching , but still with MB logo so either original or a genuine replacement .



But the front windscreen , whilst still being Sigla , does not have the MB logo - so I presume an aftermarket replacement ) it does have a small circular aperture in the blacked out area which aligns with what I take to be the rain sensor - again , perhaps the car just needs a code cleared ( and obviously the sensor reconnected ) to get auto wipers working again ? I had that area stripped out when I fitted the auto dimming rear view mirror ( which is a great thing ) .

 

[Gbrowncls55]

I had exactly the same with my cls . Had it charged at Kwikfit but light remained on and no aircon. 20 mins of fidling to no avail so went home. Did a bit of research and found that when the system turns itself off due to low refigerant levels it stores it in the fault memory but with no code showing up. Dont ask me why or even if its true. However on that basis I plugged in the icarsoft mb2. Sure enough no aircon fault codes at all so just did a clear all fault codes anyway and up pops the aircon ,no red light and has worked perfectly since.....worth a try. Dont quite know why it works if you start it with the button pressed but on regular start up in sounds like the faultcode (non code) is still in there preventing it from operating

 

[Gbrowncls55]

Sorry didnt read it all .glad you fixed it in much the same way.