Audi Allroad BHW TDI conversion.

Wing_man

Active member
Joined
May 17, 2011
Location
Trenton on
TDI
Allroad BHW
So I tried pulling some DTC's yesterday... I'm rather new to VCDS (picked up my first cable and software a few months ago) and I'm not 100% sure which block to check out. I've tried all the ones that sound like it could be linked to the a/c, and so far most of them have said '' cannot communicate with controller '' or something like that. I will be fiddling around with some of the wiring. I know that I have spliced the wires that are color matched:
Black and Yellow and Black and Grey are spliced from BHW harness ---> Audi harness.

4. gn/bl (green/blue) going from A2 to the ecu. This appears to be the engine speed signal.
Perhaps if I spliced this one into the passat's rpm signal??? Which pin could that be on the T90 connector?
 

Ifixit

Veteran Member
Joined
Feb 13, 2011
Location
Waitsfield, VT
TDI
97 B4 Passat GLX TDI Wagon & 99 Golf & 05 Passat 4motion Manual & 04 Audi A4 Avant
Any fault codes?
use VCDS button: 08-auto HVAC then fault codes

Maby someone else can chime in but I think some inst cluster also has rpm sq wave signal out..
EDC16 only has rpm out via can I believe
 

jonlowe

Veteran Member
Joined
Aug 19, 2012
Location
Northern AL
TDI
2005 Passat GLS Wagon, 5 speed conversion, GBSM
So I tried pulling some DTC's yesterday... I'm rather new to VCDS (picked up my first cable and software a few months ago) and I'm not 100% sure which block to check out. I've tried all the ones that sound like it could be linked to the a/c, and so far most of them have said '' cannot communicate with controller '' or something like that. I will be fiddling around with some of the wiring. I know that I have spliced the wires that are color matched:
Black and Yellow and Black and Grey are spliced from BHW harness ---> Audi harness.

4. gn/bl (green/blue) going from A2 to the ecu. This appears to be the engine speed signal.
Perhaps if I spliced this one into the passat's rpm signal??? Which pin could that be on the T90 connector?
I couldn't find that function on the BHW ecu. It may be there, but no clue what pin. My WAG is that the Passat gets rpm thru the CAN bus.

Are you using a genuine VCDS cable, or a generic cable and VCDS lite? If genuine, go to autoscan, and select your vehicle type, Audi A6, and do an autoscan. It will take maybe 10 minutes, and will give you all fault codes on each module in the car.

Sent from my Nexus 5 using Tapatalk
 

jonlowe

Veteran Member
Joined
Aug 19, 2012
Location
Northern AL
TDI
2005 Passat GLS Wagon, 5 speed conversion, GBSM
BTW, what clutch, pressure plate, flywheel did you use? Any spacers required or other mods?

Jon
 

Wing_man

Active member
Joined
May 17, 2011
Location
Trenton on
TDI
Allroad BHW
BTW, what clutch, pressure plate, flywheel did you use? Any spacers required or other mods?

Jon
MK4 1.8t clutch/flywheel/pressure plate. Remember to insert a pilot bearing into the BHW's crank shaft, the auto torque converter set-up dosen't require it...!

I'll re-scan the car tonight... I don't have a genuine cable so I have limited functionality... I'll keep you posted though!
 

Wing_man

Active member
Joined
May 17, 2011
Location
Trenton on
TDI
Allroad BHW
Any fault codes?
use VCDS button: 08-auto HVAC then fault codes

Maby someone else can chime in but I think some inst cluster also has rpm sq wave signal out..
EDC16 only has rpm out via can I believe
I'll could try plugging the rpm signal from the instrument cluster to the a/c control head...! If that was the missing link to the a/c control head (E87) kicking the a/c compressor into gear that would be pretty sweet... I'll have a look and see what wire that could be aswell.
 

Wing_man

Active member
Joined
May 17, 2011
Location
Trenton on
TDI
Allroad BHW
I'll could try plugging the rpm signal from the instrument cluster to the a/c control head...! If that was the missing link to the a/c control head (E87) kicking the a/c compressor into gear that would be pretty sweet... I'll have a look and see what wire that could be aswell.
So having trouble finding an rpm signal... Also, where are all the T10 connectors (audi A6 electronic box plenum chamber)?
 

jonlowe

Veteran Member
Joined
Aug 19, 2012
Location
Northern AL
TDI
2005 Passat GLS Wagon, 5 speed conversion, GBSM
If I understand what you are asking, the T10 connectors shown on the climate control wiring diagram are located behind the kick panel (called the lower A-pillar trim) on the drivers side. I'd attach a PDF of how to remove it if the forum would let me, but it is pretty straight forward.
 

nate0031

Veteran Member - TDIClub Contributor
Joined
May 14, 2012
Location
SE Ohio
TDI
96 B4 Passat
So you're using the single mass 1.8t setup? The Valeo kit? Does it seem to hold the stage 2 tune well?
 

Wing_man

Active member
Joined
May 17, 2011
Location
Trenton on
TDI
Allroad BHW
So you're using the single mass 1.8t setup? The Valeo kit? Does it seem to hold the stage 2 tune well?
Yes Valeo kit, no issues, works as advertised.

So in other news, yesterday I played around again (after a 12 hr shift)... I attempted to make the ''sensor'' dash light on the information panel disappear by tricking the wiring with a resistor. No dice. I will have to buy the sensor from the 2.7 and find a way to install it into the tdi oil pan.

But wait! There's more!

Here are all the 08 air EVAP codes... I feel like I have a lot of work to do, but I have a lot more sense of direction... Good call on the VCDS!

 

jonlowe

Veteran Member
Joined
Aug 19, 2012
Location
Northern AL
TDI
2005 Passat GLS Wagon, 5 speed conversion, GBSM
Clear the codes, drive it for awhile, try to use the climate control, rescan, and see what shows up. Those may be old codes.

Sent from my Nexus 5 using Tapatalk
 

vwztips

Veteran Member
Joined
Aug 30, 2009
Location
Greenville, SC
TDI
2005 Passat GLS Wagon TDI 5 spd manual w/BSM delete 2011 Tiguan TDI/DSG 2005 Audi A4 Avant 6MQ TDI 2011 BMW X5 35d
Wing_man you need to hurry up and figure this out. My A6 should be arriving anytime now! :D
 

Wing_man

Active member
Joined
May 17, 2011
Location
Trenton on
TDI
Allroad BHW
Wing_man you need to hurry up and figure this out. My A6 should be arriving anytime now! :D
Its coming along. I have erased my dtc's and rescan tonight... I'm getting close, I think perhaps my ac system has a leak... That wound explain the low pressure sensor acting up. As always more to follow.
 

Wing_man

Active member
Joined
May 17, 2011
Location
Trenton on
TDI
Allroad BHW
Okay, so after clearing codes, driving and re-scanning :

-00819 High Pressure sensor (G65) 07-00 - Signal too low

-01592 - Air Quality sensor (G238) 57-00 - Electric circuit Failiure

My question is, Would the G65 hi press sensor cause the A/C to go into safe mode and lock out the a/c? There is zero pressure in the system (I checked by depressing one of the fill valve stems, I must have a leak somewhere)...!

Getting the A/C to work would be amazing, I have go see THE girlfriend next week in Ottawa (3hr drive).
 

jonlowe

Veteran Member
Joined
Aug 19, 2012
Location
Northern AL
TDI
2005 Passat GLS Wagon, 5 speed conversion, GBSM
While I can't answer that question, did the air-conditioning work before you started all of this?

The pressure sensor will certainly keep the compressor clutch from engaging.

It sounds like it is at least talking to the ecu now, since you didn't get a code for that.

Sent from my Nexus 5 using Tapatalk
 

Wing_man

Active member
Joined
May 17, 2011
Location
Trenton on
TDI
Allroad BHW
While I can't answer that question, did the air-conditioning work before you started all of this?

The pressure sensor will certainly keep the compressor clutch from engaging.

It sounds like it is at least talking to the ecu now, since you didn't get a code for that.

Sent from my Nexus 5 using Tapatalk
Yes a/c worked well before all of this... If the pressure sensor will stop the clutch from engaging, well then that's my next step. Re-fill the system, find/fix the leak, then attempt to re-engage the air conditioning!
 

jonlowe

Veteran Member
Joined
Aug 19, 2012
Location
Northern AL
TDI
2005 Passat GLS Wagon, 5 speed conversion, GBSM
No clue if the air quality sensor will keep it from working.

The pressure sensor is a safety to keep from burning up the compressor without coolant in most modern a/c systems. It may have another purpose also in the climate system.

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Greg Davis

Member
Joined
Jun 29, 2011
Location
Matthews, NC
TDI
2011 Jetta
Something else to worry about. Some systems (most of the newer ones) have a low-pressure switch so that if the freon level gets too low it will prevent the compressor from pressurizing. Therefore, you have to find a way to bypass the switch so that the compressor will run to allow you to refill it(!). Facing that issue with my Land Rover project right now.

By the way - LOVE this project! You've got me trying to figure out how to convince the wife that we need to take her 4 week old (to her) '03 Allroad and convert it. I drive an '11 Jetta TDi with a Unitronics tune and it is an absolute JOY to drive.
 

nate0031

Veteran Member - TDIClub Contributor
Joined
May 14, 2012
Location
SE Ohio
TDI
96 B4 Passat
The low pressure switch will be reset when you begin to charge. The bottle pressure is ~70 PSI, which is what the system expects. The AC should be set to max with fan speed on high, then you begin to charge. Once system pressure is raised by your refrigerant bottle, the system will engage the compressor. At that point, you should see low side pressures around 30 PSI, and once you've charged the proper amount, 150-250 on the high side. The ECU should cycle the fans as high side rises to help keep pressures in check, although their operation varies by model.

You should never have to bypass the low or high pressure cutoff switches. There may an oddball car out there that might need that, but I've never seen it.

Make sure you're charging liquid into the low side.
 

Wing_man

Active member
Joined
May 17, 2011
Location
Trenton on
TDI
Allroad BHW
I will be charging the a/c on my first day off, sunday.... Got bored after work tonight, and decided to end the immobiliser's light once and for all ( flash... flash... flash... almost as annoying as driving without a/c and cruise control.)

So I took the cluster apart.



Removed the rpm dial... Even with the blurry picture you can clearly see the immobiliser's cutout on the right. Car with key symbol... I hate that symbol.



Here I am filling in the symbol with rocker guard on the backside of the rpm dial.



Result was perfect, after re-assembly, there was zero light coming through the cutout... Here I am holding the dial close to my light... No more Car with Key!

 

Losha

Veteran Member
Joined
Mar 8, 2005
Location
Sioux Falls, SD
TDI
06 Jetta TDI DSG, 2001 Golf TDI, Audi S6, A8, Toureg
Okay, so after clearing codes, driving and re-scanning :

-00819 High Pressure sensor (G65) 07-00 - Signal too low

-01592 - Air Quality sensor (G238) 57-00 - Electric circuit Failiure

My question is, Would the G65 hi press sensor cause the A/C to go into safe mode and lock out the a/c? There is zero pressure in the system (I checked by depressing one of the fill valve stems, I must have a leak somewhere)...!

Getting the A/C to work would be amazing, I have go see THE girlfriend next week in Ottawa (3hr drive).

Yes G65 sensor would cause your A/C compressor not kicking it as it sees the pressure is too low. I would suggest take car into shop and have them using A/C machine recover first then pull vacuum and leak test system, if it holds 30hg vacuum for 5-10 min without needle moving then you have no leaks, then recharge system properly using machine should take about 600g of freon. I know some of you will say that could recharge A/C with those cans from store but how would you know how much freon there is already in system and if has small slow leak or not??? yes those cans have pressure gauge, but the pressure reading could be showing high enough (with in specs) but you could have hot pressurized air in there instead of pure freon. So if it was me I would have complete system recharged properly using proper equipment and ways.

As far as for codes regarding Air quality sensor, I wouldn't be too concerned about it as it for quality for air entering cabin, lot of times i seen that code with having dirty cabin filter, and once we changed filter the code cleared itself.
 

nate0031

Veteran Member - TDIClub Contributor
Joined
May 14, 2012
Location
SE Ohio
TDI
96 B4 Passat
You can get a gauge set and vacuum pump for ~$150. That's what I did. Systems I work on have leaked down, so I'm not releasing refrigerant to atmosphere. Look at a pressure/temperature chart for r134a. If the car is cold (ambient temperature) and it's 60° out, system pressure should be 57.5 PSI. If it's 70° out, then 71.2 PSI, etc. If your pressure is anything lower than what the P/T chart gives for the temperature, you know there is no refrigerant in liquid form in the system, just a small amount of gas. Given that the low pressure cutoff is keeping the compressor off, unless the switch is faulty, you have no liquid refrigerant in the system, only a small amount of gas. That's assuming it isn't completely flat. Open the system, replace all your O-rings (~$10 from RockAuto), hook it up to the vacuum pump and let it vacuum for a half hour (I usually let it go an hour). Take note of your system vacuum, then close all valves and kill the vacuum pump. I wait a half hour then recheck. If the system maintained the vacuum, you should be good. Hook up everything to the cheap Walmart r134a can. Get the stuff that's just plain r134a, no system superchargers, gaping hole sealants, etc etc. Once all connected, weigh the can on a cheap digital gram scale (must be connected to account for any weight of the hoses etc). Charge the system to whatever weight is specified under the hood, you'll probably need multiple cans. Just keep weighing the cans till their weight decreases commensurately. I usually go an ounce over to account for whats lost to the charging hoses/manifold and disconnect. If you have a Harbor Freight near you, they have a changing manifold and vacuum pump for $150. Not the highest quality, but works for the hobbyist. I've been using it for 5 years now on various cars, always pulls a strong vacuum.
 

vwztips

Veteran Member
Joined
Aug 30, 2009
Location
Greenville, SC
TDI
2005 Passat GLS Wagon TDI 5 spd manual w/BSM delete 2011 Tiguan TDI/DSG 2005 Audi A4 Avant 6MQ TDI 2011 BMW X5 35d
You can also loan a tool for the pump from Autozone
 

Wing_man

Active member
Joined
May 17, 2011
Location
Trenton on
TDI
Allroad BHW
Fuel economy = a reliable 6.2L/100km @ 125kph or an incredible 5.8L/100Km @ 105kph give or take. As far as the A/C system, I've found a leak in the system, I need to replace a line and perhaps a few O-rings in order to charge the system properly. It's getting properly cold in eastern Ontario already, and we are expecting quite the winter. So I'm thinking about fixing the A/c next spring... Not worth it as of now.

Thanks very much for the air conditioning knowledge!

Car has been 100% reliable, over 5000km done, I've filled up 6 times, zero major issues... The only thing is the turn signals don't flash anymore, they just stay on when triggered. I've diagnosed it as a bad relay in the hazard switch.
 

Wing_man

Active member
Joined
May 17, 2011
Location
Trenton on
TDI
Allroad BHW
Another interesting thing is that when the car is @ level II ride height the fuel economy gets instantly worse by almost .2L/100K! Go figure!
 
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