W124 '95 E280 4 Speed Auto Estate, Diavia A/c Issues

JensH

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I posted a short novella on the after-factory Diavia ECU-MAN System a few months ago, having got mine working well.
I have two queries:

Symptoms:
1 My recirculation button flashes permanently (apart from when recirculation is engaged when it is constant as normal) - has been doing this for about 3 weeks. I have web-searched and found Diavia Technical Information Bulletin 26, which has a troubleshooting chart. This says the flashing LED means "Malfunction of the External temperature or Evaporator temperature sensors (disconnected or in short circuit)." I cannot find an obvious connection to an Evaporator sensor on the Diavia set-up and no sensor is listed in the original specification, although it does list an External temperature sensor, which is also available as a part - and I know exactly where this probe is on my car;

2 My gas volume is Kg. 0.350. I have the original Diavia system specification (parts list and notes) which states "The quantity of gas R134a necessary for charging the system is Kg. 0.350 (±0.020)"; Diavia Technical Information Bulletin 5, however, stated the old-refrigerant R12 volume as "Kg. 1.150 (±0.050)". An all-dealer USA MB bulletin, October 1996, recommended the following after R12 to R134a conversion 900g (0.9 Kg), but, of course, that is for factory specification A/C or Climate Control.

3 My compressor appears to have stopped switching on.

So, my questions are:
(1) Does the Diavia ECU-MAN system fitted after-factory, actually have an evaporator temperature sensor and, if so, is it located in roughly the same place as the MB one - on the side of the heater box?

(2) I am using 0.350 Kg as per the specific Diavia instructions, although several people have commented that this is a very low volume. Does anyone with a working Diavia system recommend anything else? Btw, as a late model, my car has only ever been R134a - is is basically the same Diavia system as the W210.

Cheers,


Jens
 
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JensH

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Sorted! W124 '95 E280 4 Speed Auto Estate, Diavia A/c Issues

Hi all,

No replies, but now sorted, so I thought I'd update in case it helps anyone else with a Diavia A/C system.

1. The Diavia system does, indeed, have an evaporator temperature sensor, in roughly the same place as you will find an MB-installed on; in RHD cars it is under the O/S dash just inside the parking-brake assembly. It is not listed as a separate item on the Diavia components contents list, because it is part of the "electrics" package (looms etc), which is not itemised. I've attached pix of the location (involving an installer-drilled silicon sealed hole in the heater casing) and the probe itself. The two wires are routed to the multi-connector in the Diavia ECU usually, as with mine, bracketed under the dash;

2. I removed and checked the probe, giving it a clean. It was a little pitted. I also cleaned both the ribbon and 16-way connectors on the ECU and re-connected them. I am not sure whether there was a short or not, but I also taped off all unused wiring (basically the RPM wiring and plug). Anyway the flashing LED has stopped and all seems fine;

3. Compressor is working normally.

If anyone needs information on a Diavia system, please send me a PM and I can let you have what I have, which is:

i) Original Diavia component list and (brief) installation notes;

ii) Technical Information Bulletins 12, 14, 26 & 31, with various bits of technical help including on wiring and error codes.

Cheers,


Jens
 

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smithy22

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nice one ,the ac compressor on my 300td w124 has been disconnected one of my t do jobs is to reconnect and get it going .
 
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JensH

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W124 Diavia A/c System

nice one ,the ac compressor on my 300td w124 has been disconnected one of my t do jobs is to reconnect and get it going .

Cheers,

if you have a Diavia system, let me know if you'd like me to send through the documents I have. Just PM me your e-mail...

If your 300TD is pre-facelift, then there are a some issues that you might want to bear in mind - you may need to convert from R12 to R134a gas, although an R12 substitute like RS24 may be ok.

You may also need to check whether your compressor has an RPM sensor. The earlier Diavia systems did have one. Later models did not or, if, like me, the compressor was replaced then it may have been with one without an RPM sensor. In this case, it is VITAL that the wiring for this sensor is disconnected from the Diavia CPU. That is the 8-pin connector in the middle of the back of the CPU. If you do not disconnect it the CPU it will cause the compressor not to switch and it will default to off.

This may explain why you think your compressor is disconnected. If there is still a single green wire running down to the compressor that may be all the connection you need. My RPM wiring (engine-side) is tethered off just behind the ABS system components, front N/S engine bay. That is where the single green wire splits out from the Diavia loom.

Jens :)
 

Andy A

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1976 W115 230.4, 1996 C124 E220, 1996 W210 E230, 2004 C215 CL500
Hi JensH, hope you are still on here, I appreciate this is quite an old thread but without all the brilliant information about these systems you've posted I'd never have got mine working. I did the last bits today and now I've got ice cold A/C. Thanks :)
 
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JensH

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Hi JensH, hope you are still on here, I appreciate this is quite an old thread but without all the brilliant information about these systems you've posted I'd never have got mine working. I did the last bits today and now I've got ice cold A/C. Thanks :)
Hi Andy,
I am really delighted to hear this and it makes membership and the occasional posting very rewarding. I still have my flashing recirculation button, which I reckon is down to an over-zealous car-audio technician having snipped a wire behind the dash somewhere - several hours to sort that one. As long as your ECU keeps working, though, the DIAVIA system should do a job...
I haven't posted for a while, but will need to do so soon - My sunroof has packed up (opens, but won't close, so switch, I expect), and I have a rather worrying "stall on hard steering lock" issue, which needs resolving!
Having said that I've done nearly 60k miles in my E280 since 2013, with really very little trouble, including 5 trips to the South of France.
Cheers,
Jens
 

Silberpfeil91

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W124 230E 1991 Automatic and Cat
Sorted! W124 '95 E280 4 Speed Auto Estate, Diavia A/c Issues

Hi all,

No replies, but now sorted, so I thought I'd update in case it helps anyone else with a Diavia A/C system.

1. The Diavia system does, indeed, have an evaporator temperature sensor, in roughly the same place as you will find an MB-installed on; in RHD cars it is under the O/S dash just inside the parking-brake assembly. It is not listed as a separate item on the Diavia components contents list, because it is part of the "electrics" package (looms etc), which is not itemised. I've attached pix of the location (involving an installer-drilled silicon sealed hole in the heater casing) and the probe itself. The two wires are routed to the multi-connector in the Diavia ECU usually, as with mine, bracketed under the dash;

2. I removed and checked the probe, giving it a clean. It was a little pitted. I also cleaned both the ribbon and 16-way connectors on the ECU and re-connected them. I am not sure whether there was a short or not, but I also taped off all unused wiring (basically the RPM wiring and plug). Anyway the flashing LED has stopped and all seems fine;

3. Compressor is working normally.

If anyone needs information on a Diavia system, please send me a PM and I can let you have what I have, which is:

i) Original Diavia component list and (brief) installation notes;

ii) Technical Information Bulletins 12, 14, 26 & 31, with various bits of technical help including on wiring and error codes.

Cheers,


Jens
Hi Jens, really like your thread about the Diavia A/C issues on an W124. I just took over my father`s E230 W124 from 1991. Your thread is very helpful in restoring it`s Diavia system. While having been able to sort out some electric issues already, like finding and replacing defect external temperature sensor, I still have some way to go and would ask for your help. May I ask you to please send me the technical documentation and especially the bulletins you have mentioned? The compressor does not start and I would want to find some information about this. You mentioned some RPM cabling issues potentially? Your help would be very much appreciated! Best regards, Jürgen
 


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