2.0 TDI CGLC Cam Shaft pressfit gear slipped?

[BJV]

My Q5 was in for its 120,000km Cam belt change service. A few days later on the first high way trip while overtaking the car goes into limp mode.

I pulled over and turned it of and on, but would not start. Only cranks for 1 sec and then stops. Got out the laptop and VAG-COM to find this code:

P0299 00 [01100101] - Control Range Not Reached
Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 1
Mileage: 120012 km
Date: 2025.01.20
Time: 08:51:59

Engine RPM: 2296.50 /min
Normed load value: 99.6 %
Vehicle speed: 68 km/h
Coolant temperature: 91 °C
Intake air temperature: 28 °C
Ambient air pressure: 980 mbar
Voltage terminal 30: 14.340 V
Unlearning counter according OBD: 40
Charge air pressure: specified value: 2550 hPa
Charge air pressure: actual value: 1485 hPa
Air mass: actual value (mg/stroke): 394.0 mg/stroke
EGR Solen.val.: actual value: 99.67 %
Throttle valve adapter: actual value: 99.99 %
Charge air pressure actuator: acknowledgment: 84.29 %
Mean injection quantity: 47.57 mg/stroke

4096 - Bank 1: CMP Sensor (G40) / Engine Speed Sensor (G28)
P0016 00 [01101101] - Incorrect Correlation
Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 1
Mileage: 120012 km
Date: 2025.01.20
Time: 08:52:09

Engine RPM: 887.00 /min
Normed load value: 15.7 %
Vehicle speed: 50 km/h
Coolant temperature: 91 °C
Intake air temperature: 26 °C
Ambient air pressure: 980 mbar
Voltage terminal 30: 12.100 V
Unlearning counter according OBD: 40
Engine start: start synchronization: EPM_MODE_VERIFY
Engine start: start synchronization-Test_Program_Epm st Op Mode State t UBYTE: 33

Cleared code, but car still does not start. Phone the mechanic and had the car toed in.

I was soon phone by the mechanic and told the timing marks still line up.

He then inspected and opted to replaced the belt, the car ran after this, but had very little power and the ECU code as that the Air Mass Filter signal was "implacable" (I don't have the exact code).

He then decided to open the tapped cover to check for damage. The indents on the cam shaft that allow you to access the head bolt did not align with each other. (I saw it with my own eyes, was off by a small amount). There as not visual damage to the rockers (cam followers). The assumtion was that the press fit gear on the cams has rotated. (Its the gears at the back, not the one that is driven by the belt)

He then ordered new cams, confirmed that the new shafts does indeed line up better than the old ones. Replaced both cams and the car runs fine now. No errors, lots of power.

Is it common / possible for the press fit gear to slip?
Is it just a coincidence that this happened less than 50km after the cam belt service?

I want to gather information to ensure that I do not pay for something that is his fault, and if its just coincidence, then I will pay the fair fee.

[BJV]

Here is a full scan to help identify the car after all has been fixed:
Saturday,25,January,2025,09:42:15:28792
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 11 x64
VCDS Version: 24.7.1.0 (x64) HEX-V2 CB: 0.4643.4
Data version: 20240919 DS356.3
Ross-Tech: Home

VIN: WAUZZZ8R0EA048116   License Plate: Q5
Mileage: 120040km-74589mi   Repair Order: 



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


Chassis Type: 8R-AU48 (8R0)
Scan: 01 02 03 05 08 09 15 16 17 19 2E 42 44 46 52 53 56 62 69 6D
          72 77 AC

VIN: WAUZZZ8R0EA048116   Mileage: 120040km-74589miles

01-Engine -- Status: OK 0000
02-Auto Trans -- Status: OK 0000
03-ABS Brakes -- Status: OK 0000
04-Steering Angle -- Status: OK 0000
05-Acc/Start Auth. -- Status: OK 0000
08-Auto HVAC -- Status: Malfunction 0010
09-Cent. Elect. -- Status: OK 0000
15-Airbags -- Status: OK 0000
16-Steering wheel -- Status: OK 0000
17-Instruments -- Status: OK 0000
19-CAN Gateway -- Status: OK 0000
2E-Media Player 3 -- Status: OK 0000
42-Door Elect, Driver -- Status: OK 0000
44-Steering Assist -- Status: Malfunction 0010
46-Central Conv. -- Status: OK 0000
52-Door Elect, Pass. -- Status: OK 0000
53-Parking Brake -- Status: OK 0000
56-Radio -- Status: Malfunction 0010
62-Door, Rear Left -- Status: OK 0000
69-Trailer -- Status: OK 0000
6D-Trunk Elect. -- Status: OK 0000
72-Door, Rear Right -- Status: OK 0000
77-Telephone -- Status: OK 0000
AC-Reductant Control -- Status: Malfunction 0010
-------------------------------------------------------------------------------
Address 01: Engine (J623-CGLC)       Labels:. 03L-906-018-CGL.clb
   Part No SW: 03L 906 018 JN    HW: 03L 906 018 JL
   Component: R4 2,0L EDC   X25 2929  
   Revision: 45X25---    CVN: 7201776F38D3FF8200000000
   Coding: 2A254012243601080000
   Shop #: WSC 06208 000 00000
   ASAM Dataset: EV_ECM20TDI01103L906018JN 003003
   ROD: EV_ECM20TDI01103L906018JN.rod
   VCID: 7F5AF379A77A7B72261-802A
   VINID: 9D196AAAA2220154401080411877346143

No fault code found.
Readiness: 0 0 0 0 0 

-------------------------------------------------------------------------------
Address 02: Auto Trans (J217)       Labels:| 0B5-927-156.clb
   Part No SW: 8R1 927 156 J    HW: 0B5 927 156 K
   Component: 0B5 20 TDIRdW H02 0002  
   Revision: --H02---    CVN: 00007DED
   Coding: 000001
   Shop #: WSC 06335 000 00000
   ASAM Dataset: EV_TCMDL501021 001015
   ROD: EV_TCMDL501021.rod
   VCID: 43D2BF898B12DF92029-8016

No fault code found.

-------------------------------------------------------------------------------
Address 03: ABS Brakes (J104)       Labels:. 8R0-907-379-V2.clb
   Part No SW: 8R0 907 379 AF    HW: 8R0 907 379 AF
   Component: ESP8 quattro  H09 0030  
   Revision: --------    Serial number: --------------
   Coding: 219D4C01
   Shop #: WSC 06335 000 00000
   VCID: 04507C95CE1C18AA7B3-8050

No fault code found.

-------------------------------------------------------------------------------
Address 05: Acc/Start Auth. (J393)       Labels:. 8K0-907-064-05.clb
   Part No SW: 8K0 907 064 HG    HW: 8K0 907 064 GG
   Component: BCM2 2.0      H13 0641  
   Revision: 00002001    
   Coding: 01B54000000000000000
   Shop #: WSC 06335 123 12345
   VCID: 7CA00475B6EC606A033-8028

   Subsystem 1 - Part No SW: 8K0 959 754 H    HW: 8K0 959 754 H
   Component: FBSAUDIB8 IDG  H71 0083 
   Serial number: 0513000066896015    

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC (J255)       Labels: Redir Fail!
   Part No SW: 8K2 820 043 AF    HW: 8K2 820 043 AF
   Component: KLIMA 1 ZONE  H02 0123  
   Revision: B0000000    Serial number: 01011020132238
   Coding: 342502E000
   Shop #: WSC 29914 001 1048576
   VCID: 6D863931FD96F9E284D-8038

1 Fault Found:
01274 - Air Flow Flap Positioning Motor (V71) 
            001 - Upper Limit Exceeded - Intermittent
             Freeze Frame:
                    Fault Status: 00100001
                    Fault Priority: 3
                    Fault Frequency: 1
                    Reset counter: 199
                    Mileage: 119913 km
                    Time Indication: 0
                    Date: 2025.01.15
                    Time: 12:33:43

             Freeze Frame:
                    Voltage: 14.40 V
                    Temperature: 24.0°C
                    Temperature: 24.0°C
                    Count: 11993
                    Count: 12195
                    Bin. Bits: 01000000
                    Bin. Bits: 00000011
                    Time: 255.00 s


-------------------------------------------------------------------------------
Address 09: Cent. Elect. (J519)       Labels:. 8K0-907-063.clb
   Part No SW: 8K0 907 063 DG    HW: 8K0 907 063 DG
   Component: BCM1 1.0      H16 0103  
   Revision: 07016001    Serial number: 00000051608701
   Coding: 2600C0108034AFC00081400000001D0D0F1D670827090201000004004401030100000024000000
   Shop #: WSC 06335 000 00000
   VCID: 77AA1B598FCA43326E1-8022

   Subsystem 1 - Part No SW: 8R2 955 119 A    HW: 8R2 955 119   Labels: 1KX-955-119.CLB
   Component: WWS416 130910  H11 0050 
   Serial number: 90243015130829073654
   Coding: 01DD13

   Subsystem 2 - Part No SW: 8U0 955 559 B    HW: 8U0 955 559 B  Labels: 8U0-955-559.CLB
   Component: G397_RLFS  H06 0002 
   Serial number: 21799078            
   Coding: 02005C

   Subsystem 3 - Part No SW: 8K0 941 531 AS    HW: 8K0 941 531 AS
   Component: E1 - LDS  H03 0031 
   Serial number: 00000000002709130202

   Subsystem 4 - Part No SW: 4G0 907 658 A    HW: 4G0 907 658 A
   Component: Humidity_Sens  H03 0002 
   Serial number: 8D99CEC6000000000001

No fault code found.

-------------------------------------------------------------------------------
Address 15: Airbags (J234)       Labels:* 8R0-959-655.clb
   Part No SW: 8R0 959 655 G    HW: 8R0 959 655 G
   Component: AirbagVW-AU10 H47 0610  
   Serial number: 003JPDB0RU76   Dataset Number: 8R0909602E  0010
   Coding: 30473431313030303030554A305238523053
   Shop #: WSC 06335 000 00000
   ASAM Dataset: EV_AirbaAU10SMEAU416 002004
   ROD: EV_AirbaAU10SMEAU416.rod
   VCID: 48C8A8A5B234FCCAD7B-801C

   Crash sensor for side airbag: driver side: 
   Serial number: 6334MSME7F344652J

   Front Passenger's Side Airbag Crash Sensor: 
   Serial number: 6344MSME7F06352AM

   Rear Side Airbag Crash Sensor (on driver's side): 
   Serial number: 6352QSME3C372F44R

   Passenger side rear thorax airbag crash sensor: 
   Serial number: 6362QSME303504520

   Crash sensor for front airbag: driver side: 
   Serial number: 63732SME1136417CY

   Crash sensor for front airbag: front passenger side: 
   Serial number: 63832SME1136454C-

No fault code found.

-------------------------------------------------------------------------------
Address 16: Steering wheel (J527)       Labels:. 8K0-953-568.clb
   Part No SW: 8K0 953 568 Q    HW: 8K0 953 568 Q
   Component: Lenks.Modul   H03 0003  
   Revision: C0062331    Serial number: 90862MJ50001F 
   Coding: 000037
   Shop #: WSC 06335 000 00000
   VCID: 48C8A8A5B2B4FCCAD7B-801C

   Component: E221 - MFL  H03 0004 

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments (J285)       Labels:. 8R0-920-xxx-17.clb
   Part No SW: 8R0 920 901 B    HW: 8R0 920 901 B
   Component: KOMBIINSTR.   H07 0563  
   Revision: 00400000    Serial number: WX222YY9E     
   Coding: 338622000301000C010000
   Shop #: WSC 06335 123 12345
   VCID: 313EE541212E5D02E05-8064

No fault code found.

-------------------------------------------------------------------------------
Address 19: CAN Gateway (J533)       Labels:. 8T0-907-468.clb
   Part No SW: 8R0 907 468 L    HW: 8R0 907 468 A
   Component: GW-BEM 5CAN   H11 0056  
   Revision: 1V080027    Serial number: 2741V139130250
   Coding: 80CF07FF00
   Shop #: WSC 06335 000 00000
   VCID: 48C8A8A5B2B4FCCAD7B-801C

   Subsystem 1 - Part No SW: 8R0 915 181     HW: 8R0 915 181 
   Component: J367-BDM  H07 0141 
   Serial number: 40268H14421461152159

   Subsystem 2 - Part No SW: 8K0 959 663 B    HW: 8K0 959 663 B
   Component: J532_DCDCStab  H05 0006 
   Serial number: 13273000461011200410

No fault code found.

-------------------------------------------------------------------------------
Address 2E: Media Player 3 (R199)       Labels:. 8T0-035-785.clb
   Part No SW: 8T0 035 785 A    HW: 8T0 035 785 
   Component: SG ext.Player H08 0290  
   Revision: 00000000    
   Coding: 020202
   Shop #: WSC 06335 000 00000
   VCID: 392EDD61F95E9542585-806C

No fault code found.

-------------------------------------------------------------------------------
Address 42: Door Elect, Driver (J386)       Labels:. 8K0-959-793.clb
   Part No SW: 8K0 959 793 R    HW: 8K0 959 793 P
   Component: TSG FA        H02 0510  
   Revision:             Serial number: 0000077230979 
   Coding: 011D02204001440004
   Shop #: WSC 06335 000 00000
   VCID: 4FFA83B957DA2BF2961-801A

No fault code found.

-------------------------------------------------------------------------------
Address 44: Steering Assist (J500)       Labels:| 8K0-909-144.clb
   Part No SW: 8R0 909 144 F    HW: 8R0 909 144 B
   Component: RCEPS         H38 0507  
   Revision: 00001000    Serial number: 0030909860 Dataset Number: 8R0909852H  0021
   Coding: 100000000001
   Shop #: WSC 06334 000 00000
   ASAM Dataset: EV_RCEPSAU48X 008014
   ROD: EV_RCEPSAU48X_008.rod
   VCID: 3B22C769F3E2A7524A9-806E

1 Fault Found:
2306 - Function Restriction due to Start Voltage Interruption 
          U1410 00 [00001000] - -
          [Funktionseinschränkung der Lenkung durch Spannungseinbruch bei hoher Geschwindigkeit]
          Intermittent - Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Priority: 6
                    Fault Frequency: 2
                    Reset counter: 204
                    Mileage: 120012 km
                    Date: 2025.01.20
                    Time: 08:52:08

                    Write only channel


-------------------------------------------------------------------------------
Address 46: Central Conv. (J393)       Labels:. 8K0-907-064-46.clb
   Part No SW: 8K0 907 064 HG    HW: 8K0 907 064 GG
   Component: BCM2 2.0      H13 0641  
   Revision: 00002001    Serial number: 0317095108    
   Coding: 013A0622A0B930008520053680040047
   Shop #: WSC 06335 000 00000
   VCID: 7CA00475B6EC606A033-8028

   Subsystem 1 - Part No: 8K0 951 177 
   Component: DWA-Sensor  H02 0040 

   Subsystem 2 - Part No: 1K0 951 605 C
   Component: LIN BACKUP HO  H05 1501 

No fault code found.

-------------------------------------------------------------------------------
Address 52: Door Elect, Pass. (J387)       Labels:. 8K0-959-792.clb
   Part No SW: 8K0 959 792 R    HW: 8K0 959 792 P
   Component: TSG BF        H02 0510  
   Revision:             Serial number: 0000076801242 
   Coding: 011D02204001440004
   Shop #: WSC 06335 000 00000
   VCID: 4EC49EBD50D022FA9D7-801A

No fault code found.

-------------------------------------------------------------------------------
Address 53: Parking Brake (----)       Labels: 8K0-907-801-V2.clb
   Part No SW: 8K0 907 801 M    HW: 8K0 907 801 J
   Component: EPB-4         H01 0004  
   Revision: --------    Serial number: 30000000109274 Dataset Number: 8R0909522A  0002
   ASAM Dataset: EV_ParkiBrake 001028
   ROD: EV_ParkiBrake_AU48.rod
   VCID: 392EDD61F9DE9542585-806C

No fault code found.

-------------------------------------------------------------------------------
Address 56: Radio (J503)       Labels:. 8Tx-035-1xx-56.clb
   Part No SW: 8R2 035 186 N    HW: 8R2 035 186 N
   Component: Concert3      H05 0470  
   Revision: 00000002    Serial number: AUZ5Z6M1950486
   Coding: 0400048204058D00415B071800
   Shop #: WSC 06335 000 00000
   VCID: 41DEB581918ECD82105-8014

   Subsystem 1 - Part No SW: 8T0 919 603 G    HW: 8T0 919 603 G
   Component: Display  

1 Fault Found:
03157 - Functionality limited due to Communications Disruption 
            000 - - - Intermittent
             Freeze Frame:
                    Fault Status: 00100000
                    Fault Priority: 6
                    Fault Frequency: 3
                    Reset counter: 208
                    Mileage: 120012 km
                    Time Indication: 0
                    Date: 2025.01.20
                    Time: 17:18:03

             Freeze Frame:
                    Bin. Bits: 00000000
                    Bin. Bits: 00000000
                    Bin. Bits: 00000000
                    Bin. Bits: 00000000
                    Bin. Bits: 00000000
                    Bin. Bits: 10000000
                    Bin. Bits: 00000000
                    Bin. Bits: 00000000


-------------------------------------------------------------------------------
Address 62: Door, Rear Left (J388)       Labels:. 8K0-959-795.clb
   Part No SW: 8K0 959 795 G    HW: 8K0 959 795 D
   Component: TSG HL        H01 0510  
   Revision:             Serial number: 0000077133118 
   Coding: 010C02204001240004
   Shop #: WSC 06335 000 00000
   VCID: 46D4A69DB8A0EABA257-8012

No fault code found.

-------------------------------------------------------------------------------
Address 69: Trailer (J345)       Labels:. 8K0-907-383.clb
   Part No SW: 8K0 907 383 D    HW: 8K0 907 383 D
   Component: Anhaenger     H09 0100  
   Revision: 1G001001    Serial number: 00000194377818
   Coding: 0109080000000000
   Shop #: WSC 25397 000 00000
   VCID: 3536D151D5467122BCD-8060

No fault code found.

-------------------------------------------------------------------------------
Address 6D: Trunk Elect. (J605)       Labels: 8K9-827-851.clb
   Part No SW: 8R0 827 851 B    HW: 8R0 827 851 B
   Component: J605  Master  H52 0330  
   Revision: --------    Serial number: 8R0827851B    
   VCID: 3B22C769F362A7524A9-806E

   Subsystem 1 - Part No SW: 8R0 827 852 B    HW: 8R0 827 852 B
   Component: J756  Slave  H52 0330 
   Serial number: 8R0827852B          

No fault code found.

-------------------------------------------------------------------------------
Address 72: Door, Rear Right (J389)       Labels:. 8K0-959-795.clb
   Part No SW: 8K0 959 795 G    HW: 8K0 959 795 D
   Component: TSG HR        H01 0510  
   Revision:             Serial number: 0000077132962 
   Coding: 010C02204001240004
   Shop #: WSC 06335 000 00000
   VCID: 46D4A69DB8A0EABA257-8012

No fault code found.

-------------------------------------------------------------------------------
Address 77: Telephone        Labels: 8P0-862-335.lbl
   Part No SW: 8T0 862 335 F    HW: 8T0 862 335 E
   Component: FSE_256x BT     H45 0660  
   Revision: 00000000    Serial number: 00000005679323
   Coding: 0010390
   Shop #: WSC 06335 000 00000
   VCID: 3D26C971E176A96274D-8068

No fault code found.

-------------------------------------------------------------------------------
Address AC: Reductant Control (J880)       Labels: 4G0-907-355.clb
   Part No SW: 4G0 907 355 C    HW: 4G0 907 355 B
   Component: SCR-Stg-G2    H09 0010  
   Revision: 00000000    Serial number: 132540058 Dataset Number: 8R0909571D  0014
   ASAM Dataset: EV_RDCMA00100 008040
   ROD: EV_RDCMA00100.rod
   VCID: 2B02F729038237D2DA9-807E

1 Fault Found:
196867 - Control Circuit for Reductant Pump 1 
          P208A 00 [00001001] - Open Circuit
          Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Priority: 2
                    Fault Frequency: 1
                    Reset counter: 167
                    Mileage: 120038 km
                    Date: 2025.01.23
                    Time: 17:53:51

                    Voltage terminal 30A: 14.3 V
                    Voltage terminal 30B: 14.3 V
                    Voltage terminal 87: 14.2 V
                    Reductant_pwm_duty_cycle: 0.0 %
                    Reductant_speed_pump_motor: 0 /min
                    Reductant_pump_output_stage_temperature: 34 °C
                    Reductant_heater_control_1_output_stage_temperature: 35 °C
                    Reductant_tank_temperature_sensor_actual_value: 27 °C
                    Reductant_temperature_ambient: 26 °C
                    Reductant_current_pump_motor_A: 0.0 A
                    Reductant_current_pump_motor_B: 0.0 A
                    Reductant_current_pump_motor_C: 0.0 A
                    Reductant_heater_control_1_actual_power_value: 0.0 A
                    Reductant_heater_control_2_actual_power_value: 0.0 A
                    Reductant_transfer_pump_current: 0.0 A
                    Reductant_pressure_sensor_actual_value: -50 mbar
                    Reductant_voltage_sensor_supply: 4.9 V
                    Reductant_voltage_sensor_gnd: 0.0 V
                    Reductant_level_sensor_actual_raw_voltage: 0.5 V
                    KL15 on: On
                    DIAG_Opt_H: On
                    Tank_L_SC: OFF
                    Lines_L_SC: OFF
                    DIAG_Lines_H: On
                    DIAG_Lines_L: On
                    DIAG_Tank_H: On
                    DIAG_Tank_L: On
                    MO_SCR_Dosierpumpe_Zustand: 00
                    MO_SCR_Tankheizung: OFF
                    MO_SCR_Leitungsheizung: OFF
                    MO_SCR_Transferpumpe: OFF
                    reserviert 1 0: On
                    Reserviert 2: OFF
                    Can signal MO_SCR_Dosierpumpe_Soll: 0.0 %


End----------(Elapsed Time: 01:45, VBatt start/end: 12.2V/12.2V)-----------

[Crasher]

I haven’t come across this for years, it used to happen on the V6 TDI, the cams have not changed part number and I am not aware of a TPI about it so must be a rare quality control failure HOWEVER they are available aftermarket from multiple sources such as Febi so that is telling.

[BJV]

I havenÂ’t come across this for years, it used to happen on the V6 TDI

Thank you for the reply.

I'm trying to assess what is the odds of this happening 50km after a timing job (at no fault of the guy that installed the belt).
vs
What is the odds of the belt skipping a tooth and causing this gear to slip on the shaft, but not break / damage the valves or rockers.

I'm leaning towards this is just my bad luck / coincidence that it happened. (Unless there something that a mechanic could over/under torque during the cam belt procedure that would induce this failure)

The fault code indicated that the two sensors are reading out of sync. Is the cam sensor on the "exhaust" cam that is driven by the belt or on the "inlet" cam that is driven with this rear side gear?
My reasoning is if its on the exhaust cam that is driven with the tooth belt the error code can only be a result of incorrect timing marks/belt.
If the sensor is on the intake cam then it could still be out of sync even if the belt is 100% correctly timed. Thus the gear slipped by no fault of the mechanic.

[Crasher]

There is nothing a mechanic could do after 1 klick never mind 50k.