Problem with AC, only code is 00898

[Foxgoku]

Hi All,

I'm trying to troubleshoot the AC not working on a 4-zone '07 Touareg. I've managed to experience A/C in the back zones, intermittently. However, I have not been able to find where the issue was. Below is the screenshot of the only code currently on the HVAC system. When I first got the car and ran a scan I had some additional errors, that seemed to have been caused by a low battery voltage. There was also a low refrigerant code, but after clearing that has not returned. I have checked the fuse 5A and it is not blown, I am not sure where to go next. ANY help at all is greatly appreciated.

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Address 08: Auto HVAC Labels: 7L6-907-044.clb
Part No: 7L6 907 044 T
Component: CLIMAtronic 2+2 4222
Coding: 0020030
Shop #: WSC 31414 000 00000
VCID: 45D45BD0D9B463BF5EF-5161

Subsystem 1 - Part No: 7L6 907 049 E
Component: CLIMAtronic FOND 0400

1 Fault Found:
00898 - Control Circuit A/C compressor
009 - Open or Short to Ground

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[iichel]

http://wiki.ross-tech.com/wiki/index.php/00898

 

[TFSI]

Looks like the pressure regulating valve on compressor issue. Check voltage supply to the N280 valve. But take readings MVBs on G65 pressure sensor too and post here.

 

[Foxgoku]

Thanks TFSI. I'm trying to find a place to measure the voltage for the N280 switch. If I can't find something, I'll need to pull the air intake and turbo piping. I'll post once I find a way to get the reading. I was also not able to find an MVB for the G65 pressure sender, however, I've included the G454 sensor reading, and some other snapshots that may be useful. If you know what mvb value contains the G65 information please let me know and I'll grab that as well.
G454 info

Various additional information

 

[Lgibson]

Compressor code 6 is "Econ mode activated." More than one Touareg owner has inadvertently hit the Econ button.

 

[Foxgoku]

I was cycling the econ mode off and on to trigger the compressor to be activated or deactivated. I was trying to see if I could notice a change in the load of amperage on the compressor. Also, I noticed a couple times it kicked to a 12 shutoff code after about three econ, mode 6 shutdowns. Any idea where the other end of the cable connection is for the compressor?

 

[Jack@European_Parts]

Any idea where the other end of the cable connection is for the compressor?

It is time you read the WD and observed the component locator in repair manual, in addition to SSP for design and function of the system.

https://www.google.com/#q=touareg+AC+SSP&*&spf=1

 

[Foxgoku]

Thanks for that Jack. I had went through the SSP 301 regarding the HVAC, but I don't see where it mentions the cable connections. Removing the 5A fuse for the AC unit produces additional errors when reset, which clear after the devices power on. Which leads me to believe that power is going through that fuse. Not sure what I could test to verify that terminal 15a has power. Also, upon looking at my fuses more in depth I see that SP56- located int he driver's side panel fuse box, is missing. The fuse is mentioned as "Air conditioning system relay, fresh air blower relay, 2nd speed" in a document I have found online. It should be a 15A fuse, and on my fuse card there is a fan drawn for that location. However, the slot labelled as SP56 does not have any fuse terminals connected to it. Regardless, I tried to place a fuse there, and as expected, nothing happened as there is no connection. Could it possibly be that the fuse connections were not placed correctly? Or is this maybe just a typo from the manufacturer?

 

[Jack@European_Parts]

Thanks for that Jack. I had went through the SSP 301 regarding the HVAC, but I don't see where it mentions the cable connections. Removing the 5A fuse for the AC unit produces additional errors when reset, which clear after the devices power on. Which leads me to believe that power is going through that fuse. Not sure what I could test to verify that terminal 15a has power. Also, upon looking at my fuses more in depth I see that SP56- located int he driver's side panel fuse box, is missing. The fuse is mentioned as "Air conditioning system relay, fresh air blower relay, 2nd speed" in a document I have found online. It should be a 15A fuse, and on my fuse card there is a fan drawn for that location. However, the slot labelled as SP56 does not have any fuse terminals connected to it. Regardless, I tried to place a fuse there, and as expected, nothing happened as there is no connection. Could it possibly be that the fuse connections were not placed correctly? Or is this maybe just a typo from the manufacturer?

Cut this guessing behavior out and read the WD and RTFB!
That is why we have VIN breaks and production PR-codes and they are ref in the WD typically.

 

[Foxgoku]

I apologize Jack but I don't know where the WD are available to read, buy, work from etc. I recently got this vehicle and am working on the issues. Since I haven't been able to find a reliable sight for work shop manuals, etc., I came to this sight as it was mentioned elsewhere that the group here provides helpful information. Heck, I'm even trying to decipher Russian documents as at least it is something with valid VW information that I have been able to see. Apologies, maybe I just am not privy to the correct website.

 

[TFSI]

Obviously no pressure output from AC compressor based on the readings I see now. Lets go this way:

1. Make sure you have enough freon in the AC system. You can use the AC service machine or suitable equipment to recover the current freon in car AC system to check how much is in there.If not ok recharge to the recommended level freon and recheck.
2. If above is ok, take MVb of ambient temp sender and Evaporator temp sender and post them here. Whats the reading on dash board about ambient temp? Supply to N280 will be cut off if ambient temperature is below 5 degrees C (If I remember correctly).
Sorry but I do not remember the MVB channel numbers off the top of my head, nor do I own Touareg I would have given you that info.

 

[Uwe]

I don't know where the WD are available to read, buy, work from etc.

Please see: Where do I get a Wiring Diagram?

-Uwe-

 

[Lgibson]

This vintage Touareg is covered by Bentley's DVD-ROM. Not sure if it still requires Windows XP.

 

[Jack@European_Parts]

For wookies in rare cases the N280 can be extracted and cleaned or triggered with a powerful high tension relay and resistor to save 7K at your dealer.

If you are successful you are on your way to being a Jedi.

You'd be really surprised how a ground strap to the actual compressor might help!

Now RTFB your lunch..........Erwin!

 

[Uwe]

This vintage Touareg is covered by Bentley's DVD-ROM. Not sure if it still requires Windows XP.

Yep, a Bentley CD for the T'reg would have it, but we no longer recommend those because it's a PITA to get them running on any modern Windows. So if you have one and can get it running, sure. But a one-day erWin subscription is $35 or so, and that's way less than what the CD sold for.

-Uwe-

 

[Foxgoku]

Obviously no pressure output from AC compressor based on the readings I see now. Lets go this way:

1. Make sure you have enough freon in the AC system. You can use the AC service machine or suitable equipment to recover the current freon in car AC system to check how much is in there.If not ok recharge to the recommended level freon and recheck.
2. If above is ok, take MVb of ambient temp sender and Evaporator temp sender and post them here. Whats the reading on dash board about ambient temp? Supply to N280 will be cut off if ambient temperature is below 5 degrees C (If I remember correctly).
Sorry but I do not remember the MVB channel numbers off the top of my head, nor do I own Touareg I would have given you that info.

So...I found the issue with the 00898 error. It was a faulty cable. Got the cable replaced and the error has went away, however, still no A/C. Drained the lines, which didn't have much. Verified no leaks by holding a vacuum. Recharged the system to half spec, which should be enough for the compressor to start blowing cold air. However, same condition as before. No cool air, and possibly hot. My thoughts now, are that maybe the coupling belt is stripped/removed? I'll be replacing this anyway as, I'm sure it's due, however, would there be any other issues this could be? Could it still be the N280 valve being stuck? I would think if the valve had an issue there would be a code thrown. All the temperatures seem to be correct. Here is the ambient temp and evap temp as requested. All the sensors seem to be giving Seems like there is still no motion on the freon? I'll be replacing the coupling belt and the n280 valve tomorrow, unless there is no need for the valve.

 

[Lgibson]

One other idea: Put an old school AC service manifold of gauges on it. There is an issue with the Touareg refrigerant pressure sensor lying and shutting down the system. I'm sure you know the the "Intervention Load Management" fault in 09 Central Electrics will also shut it down.

 

[Foxgoku]

Gauges read like compressor not running. Both low and high side are at around 100psi, give or take 5. No load management error or other errors on vcds. Still no a/c.

 

[Jack@European_Parts]

The N280 likes to freeze up and act funny if the ground is insufficient to the unit itself.
It can be triggered manually by enhancing a load reduction circuit.

 

[TFSI]

Have you checked if J255 is recieving wrong signal that evaporator is icing up? This will shut down or limit the AC compressor output and AC wont cool. I have had 2 experiences like this and it was the evap temp sensor. If you are sure the compressor pulley drive is good, enough freon to capacity filled in AC system (and please capacity means max freon level according to repair manual, not half filled. Always the basics must be done right!), then I would say try replacing the evap temp sensor or take MVB reading while AC is turned on on that and post it here.