Codes 17755 and 17748 after timing belt change, plus 18258, 18265, 01314
 

Before the timing belt change, I installed a stage 1 tune on the ECU, car drove fine.

After the time belt change, I am getting the above 2 codes,
plus
Auto Trans and ABS: 18258 - Powertrain Data Bus, 18265 - Load Signal; plus
HVAC and Instruments: 01314 - Engine Control Module

With those multiple codes, I suspect an interlinked common problem (missing ground?)

VCDS Wiki says regarding the 2 cam codes:

Possible Causes
Timing Belt/Chain incorrectly installed
Timing Chain probably lengthened
Camshaft Position Sensor (G40) faulty
Engine Speed Sensor (G28) faulty

Possible Solutions
Check Timing Belt/Chain installation
Use Measuring Value Blocks (MVB) to Check Timing Chain
Check/Replace Camshaft Position Sensor (G40)
Check/Replace Engine Speed Sensor (G28)

Special Notes
When found in a 30-valve V6 (yes; 2.7T) gasoline Audi engine (such as EPB or BEL), DTC 17755 may be stored as well (yes).

If both of these codes are displayed simultaneously, and the codes only appear after the motor is revved above 1800RPM (need to check), then the issue is likely that the cam chain tensioners were installed on the incorrect heads (drivers' tensioner on passenger head, etc).

Note: cam chain tensioner NOT touched. Engine seems to be running fine.




Here is the VAGcom scan:

VCDS Version: Release 11.11.5 (x64)
Data version: 20121222

Saturday,26,January,2013,16:41:16:36008

Chassis Type: 4B - Audi A6 C5
Scan: 01 02 03 06 08 15 16 17 18 22 34 35 36 37 45 55 56 57 65 67
75 76 77

VIN: WA1YD64B92N145852
-------------------------------------------------------------------------------
Address 01: Engine Labels: 078-907-551-AZA.lbl
Part No: 8D0 907 551 L
Component: 2.7l V6/5VT G 0001
Coding: 06752
Shop #: WSC 02325
VCID: 3365A75D01B9C080ECE

2 Faults Found:
17755 - Camshaft Position Sensor 2 (G163) / Engine Speed Sensor (G28)
P1347 - 35-00 - Incor. Correl.
17748 - Camshaft Position Sensor (G40) / Engine Speed Sensor (G28)
P1340 - 35-00 - Incor. Correlation
Readiness: 0010 0100

-------------------------------------------------------------------------------
Address 02: Auto Trans Labels: 01V-927-156.lbl
Part No: 4Z7 927 156 F
Component: AG5 01V 2.7l5VT USA 1818
Coding: 01002
Shop #: WSC 02325
VCID: 4999E5B57335AA50B62

2 Faults Found:
18258 - Powertrain Data Bus
P1850 - 35-10 - Missing Message from ECU - Intermittent
18265 - Load Signal
P1857 - 35-10 - Error Message from ECU - Intermittent

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 8D0-907-389.lbl
Part No: 4Z7 907 389 A
Component: ABS/ESP allrad D55
Coding: 06497
Shop #: WSC 00000
VCID: 4A9BDAB97633A148BF8

2 Faults Found:
18258 - Powertrain Data Bus
P1850 - 35-10 - Missing Message from ECU - Intermittent
18265 - Load Signal
P1857 - 35-00 - Error Message from ECU

-------------------------------------------------------------------------------
Address 06: Seat Mem. Pass Labels: None
Part No: 4B0 959 760 C
Component: Sitzmemory R1 BF 0103
Coding: 00003
Shop #: WSC 00000
VCID: 2D51B125E79D9670BAA

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: 4B0-820-043-MY2.lbl
Part No: 4B0 820 043 AD
Component: A6-Klimavollautomat 0105
Coding: 00010
Shop #: WSC 02325
VCID: 5CB72CE1CCA72FF81D4

1 Fault Found:
01314 - Engine Control Module
49-10 - No Communications - Intermittent

-------------------------------------------------------------------------------
Address 15: Airbags Labels: 4B0-959-655-AI84.lbl
Part No: 4Z7 959 655 E
Component: Airbag 8.4E 5000
Coding: 0000307
Shop #: WSC 02325 785 00200
VCID: 51A9CDD5CB659290FE2

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 4B0-920-xxx-17.lbl
Part No: 4B0 920 981 P
Component: KOMBI+WEGFAHRS. VDO D11
Coding: 06264
Shop #: WSC 08701
VCID: 3365A75D01B9C080ECE
WA1YD64B92N145852 AUZ7Z0B2126521

1 Fault Found:
01314 - Engine Control Module
49-10 - No Communications - Intermittent

-------------------------------------------------------------------------------
Address 34: Level Control Labels: 4Z7-907-553.lbl
Part No: 4Z7 907 553 E
Component: - 2C1A1 D040
Coding: 25500
Shop #: WSC 09999
VCID: 479DE38D65215C20A06

No fault code found.

-------------------------------------------------------------------------------
Address 35: Centr. Locks Labels: 4B0-962-258.lbl
Part No: 4B0 962 258 J
Component: Central Lock/Alarm D35
Coding: 15981
Shop #: WSC 02325
VCID: 306FA851F0AFFB9891C

No fault code found.

-------------------------------------------------------------------------------
Address 36: Seat Mem. Drvr Labels: None
Part No: 4B0 959 760 B
Component: Sitzmemory R1 F 0102
Coding: 00001
Shop #: WSC 00000
VCID: 2C57BC21DC879F78AD4

No fault code found.

-------------------------------------------------------------------------------
Address 45: Inter. Monitor Labels: 4B0-951-178.lbl
Part No: 4B0 951 178 A
Component: Innenraumueberw. D04
Coding: 00102
Shop #: WSC 02325
VCID: 26434E09C26BA5287B0

No fault code found.

-------------------------------------------------------------------------------
Address 55: Xenon Range Labels: 4Z7-907-357.lbl
Part No: 4Z7 907 357
Component: dynamische LWR D09
Coding: 00001
Shop #: WSC 03089
VCID: 040734811497B738054

No fault code found.

-------------------------------------------------------------------------------
Address 56: Radio Labels: 8E0-035-1xx-56.lbl
Part No: 4B0 035 195 J
Component: symphony II NP2 0050
Coding: 00201
Shop #: WSC 00000
VCID: 275D430DC561BC20406

No fault code found.

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

I checked block 93 in VAGcom and it showed 23/21 degree Phase for bank 1/2. yikes.

Redid the timing.

Now it is at a sane 6/5 degree phase.

Strange. As always, I handcrank the engine 2x. Put the cam lock bar on and check TDC. All that was dandy the first time around.

Only way phase can change (on the crank pulley, 20 degree is about an inch off the mark) is:
- belt jumped
- cam pulleys slipped on their shaft

Both are scary thought. I suspect the cams slipping. For the first time, I used a torque wrench on the cam pulley bolts (rather than the build-into-my-arm wrenchometer).

I also found after getting down there again that the timing belt tension was quite low for my taste (easily twist 90 degree).

I will do the shake down very gradually with a constant eye on channel 93.

This thread may help: https://www.audiworld.com/forums/sho....php?t=2833885