I went to start the car yesterday morning and it died almost immediately after starting up. I tried a couple more times with the same result - runs for a second and then dies. I know this to be a symptom of the immobilizer not recognizing the key, as one of my valet keys is mismatched and behaves in this same way. So I then tried my second key and also the "good" valet key but these too wouldn't allow the car to run for more than a second or two.

I was just about to go into full fault diagnosis mode, breaking out the VAGCOM, disconnecting the battery, when I read something about possible pickup connection/wiring issues. So I gave the ignition barrel a little "percussion adjustment" and moved the steering wheel adjustment up and down a couple of times. And what do you know, it fired up and stayed up...!!!

She still runs a little rough for a while after starting.

I ran a quick VCDS and turned up this...

001299 - Incorrect Immobilizer Key
P0513 - 008 - Implausible Signal - Intermittent


THE NEXT DAY...

...the car wouldn't stay running again when I tried it this morning. Even after a few thumps and wiggles around the ignition barrel it didn't fire up. I also noticed that the Trip meter was displaying the word "SAFE".

Next, I tried something I read here...

Immobilizer FAQ and troubleshooting for VW and Audi, with key replacement tips | VW TDI forum, Audi, Porsche, and Chevy Cruze diesel forum

...regarding leaving the ignition on for 10 minutes and trying again. This seemed to do the trick and the car started and ran for a few minutes before I shut it off and took my van to work instead.

When I arrived home tonight, it wouldn't start (stay running) again so I tried the 10 minute trick and it worked. Feeling confident I went for a drive around the neighborhood. Unfortunately, about a mile from home the engine started to misfire and I barely made it back. I re-ran VCDS but the immobilzer code wasn't there, just a bunch of misfire codes. However, I then ran a full scan of all modules and turned up some interesting codes from the HVAC system and steering wheel that mentioned the immobilizer...!!!


Address 08: Auto HVAC Labels: 8E0-820-043.lbl
Part No: 8E0 820 043 BM
Component: A4 Klimaautomat 2832
Coding: 00000
Shop #: WSC 00000
VCID: 6DDACBEA4BCBE874

1 Fault Found
00474 - Control Module for Immobilizer
49-10 - No Communications - Intermittent

-------------------------------------------------------------------------------
Address 16: Steering wheel Labels: 8E0-953-549.lbl
Part No: 8E0 953 549 Q
Component: Lenksáulenmodul 0601
Coding: 02021
Shop #: WSC 06335
VCID: 4182475A27D3DC14

1 Fault Found
00474 - Control Module for Immobilizer
49-10 - No Communications - Intermittent

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

The full scan is given below:


Monday,21,March,2016,18:01:13:46862

Chassis Type: 8E - Audi A4 B6/B7
Scan: 01 02 03 08 09 0F 11 15 16 17 18 36 37 45 46 55 56 57 65 67
69 75 76 77

VIN: WAUDF78E......... Mileage: 238130km/147967miles
-------------------------------------------------------------------------------
Address 01: Engine Labels: 06F-907-115-AXX.lbl
Part No SW: 8E0 910 115 M HW: 8E0 907 115 D
Component: 2.0l R4/4V TFSI 0070
Revision: --H13--- Serial number:
Coding: 0104010A190F0120
Shop #: WSC 08144 444 84095
VCID: 2B5E05F2B55F2644

6 Faults Found
004243 - Bank 1; Fuel Measuring System 2: Malfunction
P1093 - 008 - Implausible Signal - Intermittent
Freeze Frame:
Fault Status: 00101000
Fault Priority: 0
Fault Frequency: 1
Mileage: 238131 km
Time Indication: 0

Freeze Frame:
RPM: 1909 /min
Load: 37.2 %
Speed: 64.0 km/h
Temperature: 72.0°C
Temperature: 6.0°C
Absolute Pres.: 980.0 mbar
Voltage: 14.224 V

000768 - Random/Multiple Cylinder Misfire Detected
P0300 - 001 - Upper Limit Exceeded
Freeze Frame:
Fault Status: 01100001
Fault Priority: 0
Fault Frequency: 1
Mileage: 238132 km
Time Indication: 0

Freeze Frame:
RPM: 2405 /min
Load: 36.8 %
Speed: 32.0 km/h
Temperature: 75.0°C
Temperature: 6.0°C
Absolute Pres.: 980.0 mbar
Voltage: 14.097 V

000769 - Cylinder 1: Misfire Detected
P0301 - 001 - Upper Limit Exceeded
Freeze Frame:
Fault Status: 01100001
Fault Priority: 0
Fault Frequency: 1
Mileage: 238132 km
Time Indication: 0

Freeze Frame:
RPM: 2405 /min
Load: 36.8 %
Speed: 32.0 km/h
Temperature: 75.0°C
Temperature: 6.0°C
Absolute Pres.: 980.0 mbar
Voltage: 14.097 V

000771 - Cylinder 3: Misfire Detected
P0303 - 001 - Upper Limit Exceeded
Freeze Frame:
Fault Status: 01100001
Fault Priority: 0
Fault Frequency: 1
Mileage: 238132 km
Time Indication: 0

Freeze Frame:
RPM: 2731 /min
Load: 32.1 %
Speed: 20.0 km/h
Temperature: 78.0°C
Temperature: 8.0°C
Absolute Pres.: 980.0 mbar
Voltage: 14.097 V

000770 - Cylinder 2: Misfire Detected
P0302 - 001 - Upper Limit Exceeded
Freeze Frame:
Fault Status: 01100001
Fault Priority: 0
Fault Frequency: 1
Mileage: 238132 km
Time Indication: 0

Freeze Frame:
RPM: 2731 /min
Load: 32.1 %
Speed: 20.0 km/h
Temperature: 78.0°C
Temperature: 8.0°C
Absolute Pres.: 980.0 mbar
Voltage: 14.097 V

000772 - Cylinder 4: Misfire Detected
P0304 - 002 - Lower Limit Exceeded
Freeze Frame:
Fault Status: 01100010
Fault Priority: 0
Fault Frequency: 1
Mileage: 238132 km
Time Indication: 0

Freeze Frame:
RPM: 1945 /min
Load: 33.3 %
Speed: 48.0 km/h
Temperature: 80.0°C
Temperature: 10.0°C
Absolute Pres.: 980.0 mbar
Voltage: 14.097 V

Readiness: 0010 0101

-------------------------------------------------------------------------------
Address 02: Auto Trans Labels: 09L-927-760.lbl
Part No SW: 8E1 910 156 C HW: 09L 927 156 B
Component: AG6 09L 2.0TFSI USA 0040
Revision: --H01--- Serial number: 4152649
Coding: 0000002
Shop #: WSC 06335 000 00000
VCID: 2756F9C2A9B70224

No fault code found.

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 8E0-910-517.lbl
Part No SW: 8E0 910 517 E HW: 8E0 614 517 AL
Component: ESP8 quattro H06 0120
Revision: 00000000 Serial number: 00000000000000
Coding: 0004528
Shop #: WSC 06335 000 00000
VCID: 2952FFFABFA33454

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: 8E0-820-043.lbl
Part No: 8E0 820 043 BM
Component: A4 Klimaautomat 2832
Coding: 00000
Shop #: WSC 00000
VCID: 6DDACBEA4BCBE874

1 Fault Found
00474 - Control Module for Immobilizer
49-10 - No Communications - Intermittent

-------------------------------------------------------------------------------
Address 09: Cent. Elect. Labels: 8E0-907-279-8EC.lbl
Part No: 8E0 907 279 L
Component: int. Lastmodul ECE 0704
Coding: 01001
Shop #: WSC 65536
VCID: 3B7E35B2453FB6C4

No fault code found.

-------------------------------------------------------------------------------
Address 15: Airbags Labels: 8E0-959-655-94.lbl
Part No SW: 8E0 959 655 H HW: 8E0 959 655 H
Component: Airbag 9.41 H12 3840
Revision: 91H12384 Serial number: 0036N001NFUF
Coding: 0032607
Shop #: WSC 06335 000 00000
VCID: 3C7C36AE4031B1FC

Part No: 8E0 910 339 B
Component: BF-Gewichtsens. 002 0070

No fault code found.

-------------------------------------------------------------------------------
Address 16: Steering wheel Labels: 8E0-953-549.lbl
Part No: 8E0 953 549 Q
Component: Lenksáulenmodul 0601
Coding: 02021
Shop #: WSC 06335
VCID: 4182475A27D3DC14

1 Fault Found
00474 - Control Module for Immobilizer
49-10 - No Communications - Intermittent

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 8E0-920-9xx-8EC.lbl
Part No SW: 8E0 920 951 G HW: 8E0 920 951 G
Component: KOMBI+WFS 4 H14 0110
Revision: 0110 Serial number: 00000000000000
Coding: 0023259
Shop #: WSC 01308 444 70096
VCID: 2E580CE6864D536C

No fault code found.

-------------------------------------------------------------------------------
Address 46: Central Conv. Labels: 8E0-959-433-MAX.lbl
Part No: 8E0 959 433 CG
Component: Komfortgerát T7B 4035
Coding: 11896
Shop #: WSC 06335
VCID: 78F4EABE34895DDC

Part No: 8E1959801G
Component: Tõrsteuer.FS BRM 0706

Part No: 8E1959802G
Component: Tõrsteuer.BF BRM 0706

Part No: 8E0959801E
Component: Tõrsteuer.HL BRM 0606

Part No: 8E0959802E
Component: Tõrsteuer.HR BRM 0606

4 Faults Found
01371 - Alarm triggered by Door Contact Switch; Driver's Side
35-00 - -
00957 - Key 3
35-10 - - - Intermittent
01559 - Drivers Door
57-10 - Electric Circuit Failure - Intermittent
01340 - Mirror Adjustment Switch
27-10 - Implausible Signal - Intermittent

-------------------------------------------------------------------------------
Address 56: Radio Labels: 8J0-035-1xx-56.clb
Part No SW: 8E0 035 195 AC HW: 8E0 035 195 AC
Component: R Symphony2+ H02 0070
Revision: 00H02000 Serial number: AUZ1Z4F1831804
Coding: 0310112
Shop #: WSC 01126 444 66585
VCID: 68D4BAFE6429CD5C

1 Fault Found
00821 - Antenna 2 for Radio (R93)
011 - Open Circuit - Intermittent
Freeze Frame:
Fault Status: 00101011
Fault Priority: 5
Fault Frequency: 2
Reset counter: 113


End ---------------------------------------------------------------------

 

So, by way of an update...

I pulled the steering wheel and cowling and I can't see any wiring issues. It's hard to do a continuity check when you don't know where the other end of the wires go. I left the lower cowling off and put the steering wheel and airbag back on so that I could manipulate the wiring with everything powered up. Again, the car wouldn't run for more than a few seconds before conking out. Oddly, no immobilizer codes anymore though, nor any SAFE message in the ODO

I've found that if I leave the ignition on for just a couple of minutes, the car will fire up and stay up and even drive quite well for about 5 minutes before it starts to lose power and stutter. I took it for another risky drive round the neighborhood tonight and even under reasonable acceleration things seem normal for the first few minutes. When I got back, I ran the diagnostic (no check engine light) and pulled the fuel measurement code again...

004243 - Bank 1; Fuel Measuring System 2: Malfunction
P1093 - 008 - Implausible Signal - Intermittent

Does the immobilizer cut the fuel...? Is that why I'm seeing this code for what seems like an immobilizer problem?

No misfires this time but I did check the HVAC and Steering Wheel modules and they both had this code again...

00474 - Control Module for Immobilizer
49-10 - No Communications - Intermittent

I'm assuming they must be new as I left the battery off overnight and discharged the leads by shorting. I'm not deliberately resetting codes right now in case I have to go to the dealership. They're pretty clueless even with the codes. Without them (even if I give them a VCDS printout of the codes I pull) they just stand around scratching their *****.

Below are some photos of my ignition barrel for anyone who's interested...

 

I checked the codes again tonight after another short static run last night - No fuel codes but the misfire codes were back.

Tonight, I cleared everything including the 2 immobilizer codes on the HVAC and steering wheel and went out for another run. As the ignition had been on for a while to run VCDS, the car fired right up and stayed up. Again, the first few minutes were fine and I was watching the temp gauge to note when things started to deteriorate. Literally, as the needle hit its "normal" mid point on the gauge, the car started to lose power.

I limped home and ran the codes with the car still running. Same fuel measurement code was there but no misfires. I left the car running and tried to clear the code but it would immediately pop up again, over and over. Eventually I shut the engine down and cleared it. I started her up again and it did not return.

As everything was warmed up, I decided to run "Readiness". I ran it 3 times and everything passed except the oxygen sensor. I'm now wondering if this could be part of the issue, especially given that some of the major symptoms occur literally as the car reaches temperature.

Is this when the O2 control loop goes fully closed loop?

Maybe things are fine while the O2 monitoring is open loop using defaults?

Could the fueling/misfire symptoms be caused by a failing O2 sensor?

Is it possible that the failing immobilizer symptoms (stalling out within 1-2 seconds) may be caused by a failing O2 sensor?

Odd that there are no O2 codes given that readiness fails on the sensor. What other diagnosis can I do to narrow down to or eliminate the sensor and which of the 2 O2 sensors may be at fault?

 

I'd concentrate first on why the immobilizer went up. Your scan clearly states that there's no communication and intermittently losing it as well.

 

This turned out to be a MAF issue. MAF replaced and all seems good.

The immobilizer thing was a complete red herring and I made it worse during early diagnosis by using a known bad key, which then threw immobilizer codes.