Heat issue - no codes

redbat · Jan 27, 2019

Hey, so I'm kinda at my wits end with the heat problem I'm having with my '08 Avant. The issue is that there is no heat coming from the vents even at max heat and fans on full. No vents, either side, top or bottom. I CAN get SOME heat from the defrost but only when "Econ" is on. I believe the problem is with some temperature sensors, but I can't quite figure out how - hopefully I'm just being stupid.

Here's my JPPSG Info:

2008 Audi A4 B7 Avant. Don't have a photo of the build tag, but it's got the BWT engine and the transmission is a 09L. Car is stock except for an ECS catch can. I've also disabled the TPMS. Scan at the bottom of this message.

Recently (within 6 months) replaced the oil filter housing, fuel injectors, vacuum pump, coolant flange and coolant temperature sensor.

Here's what I've done so far with the current issue:

I have no codes in VCDS. I have replaced the heater core. I have ensured that there is no air in the system by using this tool to refill the system after I hooked everything back up again.

I think the thermostat is fine, as the temperature gauge is always rock-steady in the middle of the range when the car gets up to temp.

I ran through the adaptations in VCDS for the comfort system, and there were no issues.

Here's where it gets weird. When it was going through the tests, I DID get hot air out of all of the vents, which means the servos are all fine, and the flaps are all fine. I pulled measuring values on the temperature sensors, and it's very weird (to me, anyway):

Code:

                Address 08: Auto HVAC  (8E0 820 043 BM)

15:53:46
  33.0°C   Left Footwell Vent Temp. (G261)
  31.2°C   Right Footwell Vent Temp. (G262)
  33.6°C   Left Vent Temp. (G150)
  30.6°C   Right Vent Temp. (G151)
  19.5°C   Measured Ambient Temp. (G17)
  22.4°C   Temperature Actual (G59)
  15.2°C   Temperature Actual (G60)

Those values were pulled after the car got up to temp. I had the temp up to 91 F, fans at max. It seems logical to me that I'm not getting hot air because it thinks it's already in the 90's, but I don't think ALL 4 temp sensors could have gone bad at the same time...could they?

Also, the one code that is showing in the logs is probably because I stopped the adaptation sequence during the crash test sensor test.

Here's the log - any help or ideas would be appreciated!

Code:

Saturday,26,January,2019,16:10:10:30993
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 7 x64
VCDS Version: 18.9.1.0 (x64)  HEX-V2 CB: 0.4436.4
Data version: 20190114 DS296.0
www.Ross-Tech.com


VIN: WAUKF78E18AXXXXXX   License Plate: JENNA01262018
Mileage: 216130km-134296mi   Repair Order: 



--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


Chassis Type: 8E (8E - Audi A4/S4/RS4 B6/B7 (2001 > 2008))
Scan: 01 02 03 08 09 0F 11 15 16 17 18 25 36 37 45 46 55 56 57 65
          67 69 75 76 77
 
VIN: WAUKF78E18AXXXXXX   Mileage: 216130km-134296miles
-------------------------------------------------------------------------------
Address 01: Engine        Labels:. 06F-907-115-AXX.clb
   Part No SW: 8E1 910 115 G    HW: 8E0 907 115 D
   Component: 2.0l R4/4V TFSI     0010  
   Revision: 5EH15---    Serial number: XXXXXXXXXXXXXX
   Coding: 010C010A190F0120
   Shop #: WSC 06335 000 00000
   VCID: 2615F57014E09C27C41-8072

1 Fault Found:
005634 - Power Supply Terminal 30 
               P1602 - 002 - Voltage too Low - Intermittent
             Freeze Frame:
                    Fault Status: 00100010
                    Fault Priority: 2
                    Fault Frequency: 1
                    Reset counter: 255
                    Mileage: 0 km
                    Time Indication: 0

             Freeze Frame:
                    RPM: 0 /min
                    Load: 0.0 %
                    Speed: 0.0 km/h
                    Temperature: -40.0°C
                    Temperature: -40.0°C
                    Absolute Pres.: 0.0 mbar
                    Voltage: 0.000 V

Readiness: 0000 0000

-------------------------------------------------------------------------------
Address 02: Auto Trans        Labels: 09L-927-760.lbl
   Part No SW: 8E1 910 156 K    HW: 09L 927 156 B
   Component: AG6 09L 2,0TFSI USA 0080  
   Revision: --H01---    Serial number:        4408371
   Coding: 0000002
   Shop #: WSC 12345 123 12345
   VCID: 2F3B10543B1ADD6F377-807A

No fault code found.

-------------------------------------------------------------------------------
Address 03: ABS Brakes        Labels: 8E0-910-517.clb
   Part No SW: 8E0 910 517 J    HW: 8E0 614 517 BH
   Component: ESP8 quattro    H06 0140  
   Revision: 00000000    Serial number: 00000000000000
   Coding: 0004528
   Shop #: WSC 06335 000 00000
   VCID: 2E050D503C10D4673C1-807A

1 Fault Found:
01826 - Sensor for Steering Angle (G85); Supply Voltage Terminal 30 
            000 -  - 
             Freeze Frame:
                    Fault Status: 01100000
                    Fault Priority: 3
                    Fault Frequency: 6
                    Reset counter: 40
                    Time Indication: 0

             Freeze Frame:
                    Hex Value: 0x0000
                    Hex Value: 0x4222
                    Hex Value: 0x0024
                    Hex Value: 0x0190
                    Hex Value: 0x0001


-------------------------------------------------------------------------------
Address 08: Auto HVAC        Labels: 8E0-820-043.lbl
   Part No: 8E0 820 043 BM
   Component:   A4 Klimaautomat   3233  
   Coding: 00000
   Shop #: WSC 00000  
   VCID: 6D87CA5CF4866F7F45B-5160

No fault code found.

-------------------------------------------------------------------------------
Address 09: Cent. Elect.        Labels: 8E0-907-279-8EC.lbl
   Part No: 8E0 907 279 N
   Component: int. Lastmodul  USA 0907  
   Coding: 11023
   Shop #: WSC 65536  
   VCID: 3D273A1CE4663FFFB5B-4B00

No fault code found.

-------------------------------------------------------------------------------
Address 0F: Digital Radio        Labels: 8E0-035-593-SIR.lbl
   Part No SW: 8E0 035 593 N    HW:             
   Component: SDAR SIRIUS          
   Revision:             Serial number: AUZ4Z7G0209252
   Shop #: WSC 00000 000 00000
   VCID: 34311F38D21CFEB74A5-5160

1 Fault Found:
02635 - Tuner Not Enabled/Activated 
            000 -  - 

-------------------------------------------------------------------------------
Address 15: Airbags        Labels: 8E0-959-655-94.lbl
   Part No SW: 8E0 959 655 M    HW: 8E0 959 655 M
   Component:    Airbag 9.41  H01 4240  
   Revision: 91H01424    Serial number: 003CS00053BJ  
   Coding: 0032607
   Shop #: WSC 06335 000 00000
   VCID: 41DF46EC9D8E5B1FD13-8014

   Subsystem 1 - Part No: 8E0 910 339 D
   Component: BF-Gewichtsens. H03 0080

   Subsystem 2 - Serial number: 01NJD         

   Subsystem 3 - Serial number: 0001.01.0000H0300000000000ÿ†63

   Subsystem 4 - Serial number: 000000ÿ†6332DRB4069AC91D0ÿ†63

   Subsystem 5 - Serial number: AC91D0ÿ†6342DRB4067C8A29 ÿ†63

   Subsystem 6 - Serial number: C8A29 ÿ†6352ARB40338314AEÿ†63

   Subsystem 7 - Serial number: 8314AEÿ†6362ARB403383B45Kÿ†63

   Subsystem 8 - Serial number: 83B45Kÿ†63729RB40309F6AF+ÿ†63

   Subsystem 9 - Serial number: 9F6AF+ÿ†63829RB40309F6D1Vÿ

   Subsystem 10 - Serial number: 9F6D1Vÿ

No fault code found.

-------------------------------------------------------------------------------
Address 16: Steering wheel        Labels: 8E0-953-549.lbl
   Part No: 8E0 953 549 Q
   Component: Lenksáulenmodul     0801  
   Coding: 02142
   Shop #: WSC 06335  
   VCID: 41DF46EC989E5B1FD13-4B00

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments        Labels: 8E0-920-9xx-8EC.lbl
   Part No SW: 8E0 920 983 E    HW: 8E0 920 983 E
   Component: KOMBI+WFS 4     H10 0200  
   Revision: 0200        Serial number: 00000000000000
   Coding: 0023008
   Shop #: WSC 54321 444 13970
   VCID: 313F162C2D3ECB9F213-5184

No fault code found.

-------------------------------------------------------------------------------
Address 25: Immobilizer        Labels: 8E0-920-9xx-8EC.lbl
   Part No SW: 8E0 920 983 E    HW: 8E0 920 983 E
   Component: KOMBI+WFS 4     H10 0200  
   Revision: 0200        Serial number: 00000000000000
   Coding: 0023008
   Shop #: WSC 54321 444 13970
   VCID: 313F162C2D3ECB9F213-5184

No fault code found.

-------------------------------------------------------------------------------
Address 37: Navigation        Labels: 8E0-035-192-RNSE.clb
   Part No SW: 8E0 035 192 P    HW: 8E0 035 192 P
   Component: RNS-E US        H74 0250  
   Revision:      04S    Serial number: AUZBZ7G2407186
   Coding: 0301137
   Shop #: WSC 06335 000 00000
   VCID: 313F162C2D0ECB9F213-5160

No fault code found.

-------------------------------------------------------------------------------
Address 46: Central Conv.        Labels:. 8E0-959-433-MAX.clb
   Part No: 8E0 959 433 CP
   Component: Komfortgerát T7B    4336  
   Coding: 11896
   Shop #: WSC 06335  
   VCID: 015F86ECD81E9B1F913-4B00

   Subsystem 1 - Part No: 8E1959801G
   Component: Tõrsteuer.FS BRM 0706  

   Subsystem 2 - Part No: 8E1959802G
   Component: Tõrsteuer.BF BRM 0706  

   Subsystem 3 - Part No: 8E0959801E
   Component: Tõrsteuer.HL BRM 0606  

   Subsystem 4 - Part No: 8E0959802E
   Component: Tõrsteuer.HR BRM 0606  

1 Fault Found:
01366 - Opened Due to Crash Signal 
            35-00 -  - 

-------------------------------------------------------------------------------
Address 55: Headlight Range        Labels: 4F0-910-357.lbl
   Part No SW: 4F0 910 357 F    HW: 4F0 907 357 F
   Component: AFS 1           H01 0020  
   Revision: 00000001    Serial number:               
   Coding: 0000019
   Shop #: WSC 06335 000 00000
   VCID: 290FFE4C05FEB35FE93-807C

   Subsystem 1 - Part No: 8E0 941 329 A
   Component: AFS-Modul links H05 0030

   Subsystem 2 - Part No: 8E0 941 329 A
   Component: AFS-Modul rechtsH05 0030

No fault code found.

-------------------------------------------------------------------------------
Address 56: Radio        Labels: 8E0-035-192-RNSE.clb
   Part No SW: 8E0 035 192 P    HW: 8E0 035 192 P
   Component: RNS-E US        H74 0250  
   Revision:      04S    Serial number: AUZBZ7G2407186
   Coding: 0301137
   Shop #: WSC 06335 000 00000
   VCID: 313F162C2D0ECB9F213-5160

No fault code found.

-------------------------------------------------------------------------------
Address 65: Tire Pressure        Labels: 8E0-907-273.lbl
   Part No SW: 8E0 907 273 A    HW: 8E0 907 273 A
   Component: Reifendruck 3   H04 0130  
   Coding: 0062121
   Shop #: WSC 06435 000 00000
   VCID: 2A0D014000D8B847E09-5160

1 Fault Found:
01521 - Sensor for Tire Pressure 
            004 - No Signal/Communication - Intermittent - MIL ON
             Freeze Frame:
                    Fault Status: 10100100
                    Fault Priority: 3
                    Fault Frequency: 62
                    Reset counter: 33
                    Time Indication: 0

             Freeze Frame:
                    (no units): 91.0
                    Voltage: 13.90 V
                    (no units): 61.0
                        Not Recogn.
                        Not Recogn.
                        Not Recogn.
                        Not Recogn.
                    Fuel Consump.: 0.0 l/100km


End----------(Elapsed Time: 04:46, VBatt start/end: 12.3V/12.3V)-----------

Jack@European_Parts · Jan 27, 2019

Verify outside ambient temp reports proper not running interference, but since you did a core, double check this going forward.

Servo for temp heater core blend door possibly faulty, plugged in wrong sensor or out of basic setting mechanical calibration. Remove servo manually move blend door and verify heat.
Replace and calibrate as required or sort climate control issue running interference.

At least manually move it to get heat regardless because it is supposed to be cold this week.

redbat · Jan 27, 2019

Hey Jack, thanks for the quick response!

Ambient temp is about right. The servo did move the arm during the test, and I DID get hot air - the issue is that the arm does not move on its own during normal operation.

Good to know that I can manually move the arm - I'll do that, but would still like to resolve the main issue. Since all 4 temperature sensors are definitely reporting incorrect temps, are we maybe looking at a bad fuse or relay or something? I do have another B7 A4 that's working correctly that I can swap things from, but I need help with knowing WHAT to swap...

Thanks again for your assistance, really appreciated!

Uwe · Jan 27, 2019

redbat said:
Those values were pulled after the car got up to temp. I had the temp up to 91 F, fans at max. It seems logical to me that I'm not getting hot air because it thinks it's already in the 90's, but I don't think ALL 4 temp sensors could have gone bad at the same time...could they?

I think you're misinterpreting those readings. They're not what the module thinks your interior temperature is. They're the temperature of the air coming out of the vent, and 30-ish degrees C is pretty tepid when you've got the heat set to full blast.

Show us what you have in MVB 011 (all four fields).

You can also do a reality check on the hot/cold blend doors. What do you have in MVB 003 and 004 when it should be producing heat? And what happens when you crank the dials the other way to max cold?

ETA: There

-Uwe-

redbat · Jan 27, 2019

Uwe said:
I think you're misinterpreting those readings. They're not what the module thinks your interior temperature us. They're the temperature of the air coming out of the vent, and 30-ish degrees C is pretty tepid when you've got the heat set to full blast.

I'm with Jack. I suspect there's something awry with with the hot/cold blend flap.

-Uwe-

Thank you so much for the response, especially on a Sunday night! I really appreciate the assist from both of you.

Ok, understood on the temp sensors - if my math is right, 30C is about 90F, which is what I had the heater set to. It's been about 65 here in Santa Cruz today, and that reading of 30C felt like there was no heat at all, so that's why I was going down that road.

Re: the hot/cold blend flap, am I correct in assuming that's the one in the driver footwell above and to the left of the heater core? That arm DID move and I DID get heat out of all vents while VCDS was running through the output tests.

Am I looking at swapping the module, or is there something else that could be causing the flap to work in testing but not in reality?

Again, thanks so much, and apologies if any of these questions are dumb - it's been a long day.

EDIT: I also ran Basic Settings and logged the results in a CSV. They don't mean anything to me, but I did notice that the value in the "7" box never changed from "000", if that means anything. Here's a link to the CSV in Google Sheets if that's helpful.

Uwe · Jan 27, 2019

(30°C × 9/5) + 32 = 86°F

I'm not sure where the blend doors are in that car. I suspect there are two of them. You can set different temps for the driver and passenger, right?

If there's a sensor that's causing the car to think it's warmer inside than it really is, it will be the one in MVB 011.1

Get more data and play with this thing some before you even consider swapping parts out. If you're in Santa Cruz, I suspect your risk of frostbite is fairly minimal.

-Uwe-

redbat · Jan 27, 2019

Ok, at the car now with some data.

With the heater off, car idling, MVB 011 is: [15.0 C] [3180 /min] [61.0 C] [OFF]

With the heater on MAX, car idling, MVB 003 is: [233.0] [235.0] [28.0] [232.0]
With the heater on MAX, car idling, MVB 004 is: [233.0] [235.0] [27.0] [232.0]

When I switch from max hot to max cold, the A/C does kick on, and the values in 003.1 and 003.2 are [28.0] and [25.0] and 004.1 and 004.2 are [27.0] and [24.0]

I totally hear you on the frostbite risk, but unfortunately, this car belongs to my better half and she's been cold in the mornings, so I gotta fix it...

Jack@European_Parts · Jan 27, 2019

A quick test by unplugging the ambient temp sensor should make the climate control believe it needs to go balls out hot, since it thinks it's an ice box. The inverse happens when the AC won't work when it thinks it's already too cold.....

redbat · Jan 27, 2019

The one behind the bumper, or the one in the cabin?

Jack@European_Parts · Jan 27, 2019

Both..............

redbat · Jan 28, 2019

Never mind, I'm an idiot. I forgot that I forgot to take the car for a test drive, so the engine wasn't fully up to temp (I figured 25% on the temp gauge was good enough). When I looked at the coolant temperature, I realized that it wasn't hot enough to get the heater going. Took it for a drive, worked beautifully, problem solved, now I know to think things through more carefully before I freak out. :facepalm:

I also know a lot more about how the HVAC system in this car works.

Heat issue - no codes

redbat

Verified VCDS User

Jack@European_Parts

Gone But Not Forgotten

redbat

Verified VCDS User

Uwe

Benevolent Dictator

redbat

Verified VCDS User

Uwe

Benevolent Dictator

redbat

Verified VCDS User

Jack@European_Parts

Gone But Not Forgotten

redbat

Verified VCDS User

Jack@European_Parts

Gone But Not Forgotten

redbat

Verified VCDS User