2008 VW Caddy 2.0 TDI BMM DPF / EGR / IMF faults (008914 P2002, 001031 P0407, 008214 P2016)

   #1  

DieselDubz

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Hi All,

I'm looking for some advice on a series of DPF / EGR / IMF related issues on a 2008 VW Caddy 2.0 TDI with BMM code engine.

The background to the story is that the engine failed on the motorway (crankshaft broke in two) and had to go away for a rebuild. I had the bright idea of entrusting the engine removal / refit to a local workshop as I am going through a divorce and don't currently have access to my workshop, plus I considered I would lose less money this way as I would not need to take time off work to remove / refit the engine.

When I collected the vehicle, it had a bad vibration at idle which then improved with increasing RPM. This turned out to be down to the lower engine mount rubber bushes in the subframe as they had been replaced with solid rubber bushes rather than the more compliant OEM bushes which have more air than rubber. I had instructed the shop to replace all of the mounts and they had done so, just not with OEM parts.

I took the vehicle in this condition as I needed it for work and really didn't want to get into a dispute with the shop as they had been recommended by a friend and gave me a good discount etc.

I ordered the correct lower engine mount bushes and continued to use the vehicle in the meantime, after 200 miles I changed the engine oil and filter as recommended by the engine overhauler. At this point I noticed that the engine wiring loom had been damaged in various places and several clamps, brackets, supports, heat shields etc. were missing. I started compiling a list of everything to put it right.

On my commute to work a few days later (38 miles, mostly at 70mph) the vehicle went into limp mode, accompanied by the DPF amber warning light, flashing glow plug coil light and MFD message 'Particulate Filter'.

The common fault 008914 P2002 seems to be the main issue, it seems to have latched in the ECU fault memory as it returns after it has been cleared, even if the engine is not started.

I have since repaired the wiring loom, replaced damaged connectors, tested it for continuity and insulation, removed, cleaned and bench-tested the EGR valve and IMF / ASV, replaced the missing hardware on the engine (wiring clips, clamps, heat shields etc.)

Here is an autoscan from yesterday:

Code:
Saturday,09,September,2023,18:33:36:34503
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 7 x86
VCDS Version: 23.3.1.0  HEX-V2 CB: 0.4631.4
Data version: 20230421 DS346.2
www.Ross-Tech.com


VIN: WV1ZZZ2KZ9X006616   License Plate: GP08 HHC
Mileage: 323760km-201175mi   Repair Order:



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


Chassis Type: 2K (1K0)
Scan: 01 03 08 09 10 15 16 17 19 25 42 44 46 52 56 69

VIN: WV1ZZZ2KZ9X006616   Mileage: 323760km-201175miles

01-Engine -- Status: Malfunction 0010
03-ABS Brakes -- Status: OK 0000
04-Steering Angle -- Status: OK 0000
08-Auto HVAC -- Status: Malfunction 0010
09-Cent. Elect. -- Status: Malfunction 0010
10-Park/Steer Assist -- Status: OK 0000
15-Airbags -- Status: OK 0000
16-Steering wheel -- Status: Malfunction 0010
17-Instruments -- Status: OK 0000
19-CAN Gateway -- Status: OK 0000
25-Immobilizer -- 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
56-Radio -- Status: Malfunction 0010
69-Trailer -- Status: Malfunction 0010
-------------------------------------------------------------------------------
Address 01: Engine        Labels: 03G-906-021-BMM.clb
   Part No SW: 03G 906 021 RT    HW: 03G 906 021 AB
   Component: R4 2,0L EDC G200SG  2120 
   Revision: --H07---    Serial number: VWX7Z0H33NU0CL
   Coding: 0000072
   Shop #: WSC 35110 377 00172
   VCID: 025D87BBB8077D6A19F-8056
   VINID: 9E606AAAA09BA89A00006181188E561BB0

3 Faults Found:
001031 - EGR Sensor 2
               P0407 - 000 - Signal too Low - Intermittent
             Freeze Frame:
                    Fault Status: 00100000
                    Fault Priority: 1
                    Fault Frequency: 1
                    Reset counter: 255
                    Mileage: 323765 km
                    Time Indication: 0
                    Date: 2000.00.00
                    Time: 01:54:50

             Freeze Frame:
                    RPM: 0 /min
                    Speed: 0.0 km/h
                    Load: 0.0 %
                    Lambda: -3.9 %
                    Mass Air / Rev.: 820.0 mg/str
                    Mass Air / Rev.: 0.0 mg/str
                    Bin. Bits: 00000000

008214 - Intake Manifold Flap Position Sensor (Bank 1)
               P2016 - 000 - Short to Ground - Intermittent
             Freeze Frame:
                    Fault Status: 00100000
                    Fault Priority: 1
                    Fault Frequency: 1
                    Reset counter: 255
                    Mileage: 323765 km
                    Time Indication: 0
                    Date: 2000.00.00
                    Time: 01:54:50

             Freeze Frame:
                    RPM: 0 /min
                    Speed: 0.0 km/h
                    Voltage: 11.86 V
                    Duty Cycle: 100.2 %
                    Lambda: 0.0 %
                    Lambda: -1.2 %
                    (no units): 2.0

008194 - Particulate Trap Bank 1
               P2002 - 000 - Efficiency Below Threshold - MIL ON
             Freeze Frame:
                    Fault Status: 11100000
                    Fault Priority: 1
                    Fault Frequency: 1
                    Reset counter: 255
                    Mileage: 323765 km
                    Time Indication: 0
                    Date: 2000.00.00
                    Time: 01:54:50

             Freeze Frame:
                    RPM: 0 /min
                    Speed: 0.0 km/h
                    (no units): 0.0
                    Duty Cycle: 14.6 %
                    (no units): 0.00
                    Temperature: 8.1°C
                    Time: 4492.8 s

Readiness: 1 3 0 0 1

-------------------------------------------------------------------------------
Address 03: ABS Brakes        Labels: 1K0-907-379-MK60-F.clb
   Part No SW: 1K0 907 379 AC    HW: 1K0 907 379 AC
   Component: ESP FRONT MK60      0101 
   Revision: 00H11001   
   Coding: 0023254
   Shop #: WSC 00697 210 92324
   VCID: 73B3D27FF7BD44E2029-8026

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC        Labels: 1K0-820-047.lbl
   Part No SW: 1K0 820 047 HM    HW: 1K0 820 047 HM
   Component: Climatic PQ35   142 1111 
   Revision: 00142031    Serial number: 00000000000000
   Shop #: WSC 00000 000 00000
   VCID: 76B5EB6BE4CF51CA257-8022

1 Fault Found:
00229 - Refrigerant Pressure
            002 - Lower Limit Exceeded

-------------------------------------------------------------------------------
Address 09: Cent. Elect.        Labels:. 3C0-937-049-30-H.lbl
   Part No SW: 3C0 937 049 AJ    HW: 3C0 937 049 AJ
   Component: Bordnetz-SG     H54 2202 
   Revision: 00H54000    Serial number: 01000008411238
   Coding: E18A4F030004100047000000000000000008FF075C000100000000000000
   Shop #: WSC 00697 210 92324
   VCID: 71BFD8778DA176F2F05-8024

   Subsystem 1 - Part No: 2K2 955 119 C  Labels: 1KX-955-119.CLB
   Component: Wischer 060508 021  0501 
   Coding: 00038805
   Shop #: WSC 00697 

   Subsystem 2 - Part No: 1K0 955 559 AH  Labels: 1K0-955-559-AG.CLB
   Component: RLS     080508 054  0402 
   Coding: 00209133
   Shop #: WSC 00697 

2 Faults Found:
01497 - Bulb for Blinkers; Front Right (M7)
            012 - Electrical Fault in Circuit
             Freeze Frame:
                    Fault Status: 01101100
                    Fault Priority: 2
                    Fault Frequency: 4
                    Reset counter: 65
                    Mileage: 323699 km
                    Time Indication: 0
                    Date: 2005.09.13
                    Time: 31:63:63

             Freeze Frame:
                        ON
                    Voltage: 12.10 V
                        ON
                        ON
                        OFF
                        OFF
                        OFF

00988 - Lamp for Brake Light; Right (M10)
            012 - Electrical Fault in Circuit
             Freeze Frame:
                    Fault Status: 01101100
                    Fault Priority: 1
                    Fault Frequency: 1
                    Reset counter: 65
                    Mileage: 323699 km
                    Time Indication: 0
                    Date: 2005.09.13
                    Time: 31:63:63

             Freeze Frame:
                        ON
                    Voltage: 12.05 V
                        ON
                        ON
                        OFF
                        OFF
                        OFF


-------------------------------------------------------------------------------
Address 10: Park/Steer Assist (J446)       Labels:. 1K0-919-475.clb
   Part No SW: 1K0 919 475 D    HW: 1K0 919 475 D
   Component: PARKHILFE     005 1406 
   Revision: 00005000    Serial number: 0 263 004 291
   Coding: 110001
   Shop #: WSC 35110 377 08192
   VCID: 3333127FBB3D04E2C29-8066

No fault code found.

-------------------------------------------------------------------------------
Address 15: Airbags        Labels: 6Q0-909-605-VW52.lbl
   Part No SW: 6Q0 909 605 AJ    HW: 6Q0 909 605 AJ
   Component: 1C AIRBAG VW52  025 2400 
   Revision: 06025000    Serial number: 0037UR008HSY 
   Coding: 0012611
   Shop #: WSC 35110 377 00161
   VCID: 7F5B0E4FCBF51082761-802A

No fault code found.

-------------------------------------------------------------------------------
Address 16: Steering wheel        Labels: 1K0-953-549-MY8.lbl
   Part No SW: 1K0 953 549 CB    HW: 1K0 953 549 CB
   Component: J0527           051 0100 
   Coding: 0002022
   Shop #: WSC 35110 377 08192
   VCID: 74B1D163F2B343DA1B3-8020

   Subsystem 1 - Part No: XXXXXXXXXXX
   Component: E0221           002 0010

4 Faults Found:
00576 - Terminal 15
            012 - Electrical Fault in Circuit - Intermittent
00883 - Ignition Switch (D) Terminal S
            012 - Electrical Fault in Circuit - Intermittent
00884 - Ignition Switch (D) Terminal X
            012 - Electrical Fault in Circuit - Intermittent
01744 - Ignition Switch Terminal P (D)
            012 - Electrical Fault in Circuit - Intermittent

-------------------------------------------------------------------------------
Address 17: Instruments        Labels: 1K0-920-xxx-17.lbl
   Part No SW: 1T0 920 974 A    HW: 1T0 920 974 A
   Component: KOMBIINSTRUMENT VDD 2416 
   Revision: V0002000    Serial number: VWX7Z0H33NU0CL
   Coding: 0020401
   Shop #: WSC 02641 002 1048576
   VCID: 35372C67B9491AD2ECD-8060

No fault code found.

-------------------------------------------------------------------------------
Address 19: CAN Gateway        Labels:. 1K0-907-530-V3.clb
   Part No SW: 1K0 907 530 Q    HW: 1K0 907 951
   Component: J533  Gateway   H07 0062 
   Revision:   H07 01    Serial number: 040508F1000235
   Coding: E9A01F460002027401
   Shop #: WSC 35110 377 00161
   VCID: 35372C67B9491AD2ECD-8060

No fault code found.

-------------------------------------------------------------------------------
Address 25: Immobilizer        Labels: 1K0-920-xxx-25.clb
   Part No SW: 1T0 920 974 A    HW: 1T0 920 974 A
   Component: IMMO            VDD 2416 
   Revision: V0002000    Serial number: VWX7Z0H33NU0CL
   Shop #: WSC 00000 000 00000
   VCID: 35372C67B9491AD2ECD-8060

No fault code found.

-------------------------------------------------------------------------------
Address 42: Door Elect, Driver        Labels:. 1K0-959-701-MIN3.clb
   Part No SW: 1T0 959 701 H    HW: 1T0 959 701 H
   Component: Tuer-SG         006 1206 
   Coding: 0000560
   Shop #: WSC 35110 377 08192
   VCID: 3C2139439A63CB9A133-8068

No fault code found.

-------------------------------------------------------------------------------
Address 44: Steering Assist        Labels: 1K0-909-14x-GEN3.clb
   Part No: 1K0 909 144 C
   Component: EPS_ZFLS Kl. 140    2301 
   Revision: 00H15000   
   Shop #: WSC 35110 377 00161
   VCID: 2A0D0F1B60F7452A71F-807E

1 Fault Found:
00778 - Steering Angle Sensor (G85)
            000 - - - MIL ON
             Freeze Frame:
                    Fault Status: 11100000
                    Fault Priority: 2
                    Fault Frequency: 1
                    Reset counter: 255
                    Time Indication: 0

             Freeze Frame:
                    Battery Volts: 12.1 V
                        PD
                    Temperature: 13.0°C
                    Count: 2
                    Steering Angle: 0.00°
                    Count: 1
                        SteerAng n.Init


-------------------------------------------------------------------------------
Address 46: Central Conv.        Labels:. 1K0-959-433-MIN.clb
   Part No: 1K0 959 433 CP
   Component:    KSG              0401 
   Coding: 818B0C087F2D8405485AC61010C0
   Shop #: WSC 35110 377 00161
   VCID: 00598DB3B60B6F7A0FB-8054

   Subsystem 5 - Part No: 2K0 951 172
   Component: Innenraumueberw.009 4807 
   Coding: 00000000
   Shop #: WSC 00000 

   Subsystem 6 - Part No: 1K0 951 605 C
   Component: LIN BACKUP HORN H03 1301

   Subsystem 7 - Part No: 1K0 907 719 C
   Component: Neigungssensor  005 0003

No fault code found.

-------------------------------------------------------------------------------
Address 52: Door Elect, Pass.        Labels:. 1K0-959-702-MIN3.clb
   Part No SW: 1T0 959 702 H    HW: 1T0 959 702 H
   Component: Tuer-SG         006 1206 
   Coding: 0000560
   Shop #: WSC 35110 377 08192
   VCID: 3D2734478179C29224D-8068

No fault code found.

-------------------------------------------------------------------------------
Address 56: Radio (J503)       Labels:. 5M0-035-1xx-56.clb
   Part No SW: 1K0 035 186 AA    HW: 1K0 035 186 AA
   Component: Radio RCD310  012 0029 
   Revision: 00000000    Serial number: VWZ1Z2H5854728
   Coding: 0000000000
   Shop #: WSC 01286 386 08256
   VCID: 6597BC274569AA529CD-8030

1 Fault Found:
01042 - Control Module; Not Coded
            000 - -
             Freeze Frame:
                    Fault Status: 01100000
                    Fault Priority: 3
                    Fault Frequency: 1
                    Reset counter: 255
                    Time Indication: 0


-------------------------------------------------------------------------------
Address 69: Trailer (J345)       Labels:. 1K0-907-383-V2.clb
   Part No SW: 1K0 907 383 E    HW: 1K0 907 383 E
   Component: Anhaenger     H07 0050 
   Revision: 3A001001    Serial number: 00000111731254
   Coding: 4100000100000000
   Shop #: WSC 35110 377 00161
   VCID: 2F3B1E0F57152002A61-807A

1 Fault Found:
16355 - Control Module - Watchdog Timer
            014 - Defective
             Freeze Frame:
                    Fault Status: 01101110
                    Fault Priority: 3
                    Fault Frequency: 1
                    Reset counter: 2
                    Mileage: 139729 km
                    Time Indication: 0
                    Date: 2000.00.00
                    Time: 14:50:17

The G450 differential pressure sensor seems to be working fine, I have tested it with a Mityvac and also carried out the adaption in VCDS just to be sure.

The ECU isn't seeing the correct position of the IMF / ASV butterfly as the position doesn't vary during the output test and it shows up as 4.7% when the commanded position is 95.5% this presumably explains the fault code 008214 Intake Manifold Flap Position Sensor Bank 1 P2016

001031 EGR Sensor 2 P0407 Signal Too Low - Intermittent: I'm not sure about this one, in terms of sensors there are position senders within the EGR valve itself but I'm not aware of any other EGR sensors as such. There are three temp sensors, the Lambda sensor and the DPF differential pressure sensor as far as I know.

008194 Particulate Trap Bank 1 P2002 - Efficiency Below Threshold - MIL ON: this one seems to have latched in the ECU fault memory as it returns after it has been cleared, even if the engine is not started (so without any differential pressure readings from the G450). I wonder if this one can latch on once the carbon mass value computed by the ECU exceeds a certain threshold.

Here are some values I have logged which will hopefully be useful in the diagnosis.

1st: Engine Off

Code:
VIN: WV1ZZZ2KZ9X006616   License Plate: GP08 HHC
Mileage: 201174   Repair Order:



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


                Address 01: Engine  (03G 906 021 RT)

16:07:21
  95.5 %   Position (spec.) Intake Flap
  0.0 %   Position (spec.) EGR-Actuator
  0.0 %   Position (act.) EGR-Actuator
  0.0 %   Exhaust Gas Recirc. Duty Cycle
  0.0 %   Position (act.) Intake Flap
  0.0 %   Position (act.) EGR-Actuator
  0 /min   Engine Speed (G28)
         0   Exhaust Gas Recirc. Cooler
      Intake Manifold Flap Duty Cycle
  0.00   Press. Difference Particle Filter
  -2.55   Press. Difference Offset

2nd: Engine at Idle

Code:
Sunday,10,September,2023,16:08:20:34503
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 7 x86
VCDS Version: 23.3.1.0  HEX-V2 CB: 0.4631.4
Data version: 20230421 DS346.2
www.Ross-Tech.com


VIN:    License Plate: GP08 HHC
Mileage: 201174   Repair Order:


                Address 01: Engine  (03G 906 021 RT)

16:08:01
  95.5 %   Position (spec.) Intake Flap
  0.0 %   Position (spec.) EGR-Actuator
  0.0 %   Position (act.) EGR-Actuator
  0.0 %   Exhaust Gas Recirc. Duty Cycle
  4.7 %   Position (act.) Intake Flap
  0.0 %   Position (act.) EGR-Actuator
  777 /min   Engine Speed (G28)
         0   Exhaust Gas Recirc. Cooler
      Intake Manifold Flap Duty Cycle
  15.30   Press. Difference Particle Filter
  -2.55   Press. Difference Offset

3rd: Engine at 2000RPM

Code:
Sunday,10,September,2023,16:08:58:34503
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 7 x86
VCDS Version: 23.3.1.0  HEX-V2 CB: 0.4631.4
Data version: 20230421 DS346.2
www.Ross-Tech.com


VIN:    License Plate: GP08 HHC
Mileage: 201174   Repair Order:


                Address 01: Engine  (03G 906 021 RT)

16:08:46
  95.5 %   Position (spec.) Intake Flap
  0.0 %   Position (spec.) EGR-Actuator
  0.0 %   Position (act.) EGR-Actuator
  0.0 %   Exhaust Gas Recirc. Duty Cycle
  4.7 %   Position (act.) Intake Flap
  0.0 %   Position (act.) EGR-Actuator
  1995 /min   Engine Speed (G28)
         0   Exhaust Gas Recirc. Cooler
      Intake Manifold Flap Duty Cycle
  58.65   Press. Difference Particle Filter
  -2.55   Press. Difference Offset

And here are the values for the DPF:

Code:
Sunday,10,September,2023,16:11:01:34503
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 7 x86
VCDS Version: 23.3.1.0  HEX-V2 CB: 0.4631.4
Data version: 20230421 DS346.2
www.Ross-Tech.com


VIN: WV1ZZZ2KZ9X006616   License Plate: GP08 HHC
Mileage: 201174   Repair Order:


                Address 01: Engine  (03G 906 021 RT)

16:10:50
  15.0 %   Particle Filter Load Coefficient
  104.0   Particle Filter Carbon Mass
  0.0 %   Carbon Mass Learned Value
  4492.8 s   Regeneration Time (Total)
  0.0   Failed Regenerations
  0.0   Successful Regenerations

The DPF differential pressures of 15.30 at Idle and 58.65 at 2000RPM seem high, so I am initially looking at having the DPF professionally cleaned then resetting the carbon mass value. As far as I know, the DPF is original so has 200k miles.

Having repaired and tested the engine wiring loom and also bench tested the IMF / ASV for actuation, I can only surmise that the hall sender part of the valve is not working properly so I should replace the valve.

The EGR fault code, I'm not so sure about and I wonder if this could be somehow related to the IMF / ASV issue as this restricts the inlet during EGR operation in order to increase the draw through the EGR valve. If need be I will replace both the EGR valve and IMF / ASV.

I would be really grateful if anyone here could help me by offering some insight into these faults and either confirm that I am on the right track or suggest further fault isolation steps or a different approach.

Thanks a lot,
Rich
 
   #2  

Uwe

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The DPF differential pressures of 15.30 at Idle and 58.65 at 2000RPM seem high,
Yep. But have you checked the reading with key on, engine off? If it's not zero, the sensor is suspect.

FWIW, EGR and other faults will keep the ECU from regenerating the DPF, which means it will clog up.

-Uwe-
 
   #3  

DieselDubz

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Thanks for reading, really appreciate it.

The G450 reading is zero with key on, engine off (the first of the three sets of readings included in the original post). The offset value (-2.55) didn't change after an adaption and it seems to be working correctly. I do have a replacement sensor that I could try if you think it would be worthwhile?

I'm not using the vehicle until all the issues are resolved so I won't be clogging the DPF any further than it may already be.

I'll proceed with sending the DPF for a professional clean then reset the carbon mass value and I'll also replace the IMF / ASV and see what the situation looks like then.

Do you have any other suggestions based on the data provided?

I would like to better understand the meaning of the parameters relating to the DPF:
  • Particle filter load coefficient
  • Particle filter Carbon mass
  • Carbon mass learned value
Presumably there is a Carbon mass value above which the P2002 fault code is triggered, along with MIL and limp mode?

Many thanks,
Rich
 
   #4  

DieselDubz

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Hi All,

Just to update on the situation:
  • DPF cleaned by turbulent water and compressed air cleaning machine
  • DPF ash value reset to 10% of pre-clean value
  • EGR valve replaced
  • IMF / ASV replaced
I was expecting to be able to carry out an adaption of the new EGR valve and IMF / ASV in VCDS but the adaption channel for the EGR said 'unavailable' and there didn't seem to be one for the IMF / ASV. I have carried out the EGR basic settings check and it seems to be working correctly.

The differential pressure values from the G450 sensor have reduced massively following the DPF cleaning.

One issue still remains, despite replacing the IMF / ASV, the commanded position and actual position are still at odds and the valve does not physically move when the output test is selected. The valve remains fully open, with commanded position of 95.5% and actual position reported as 4.7%. If I manually move the butterfly by hand, the reported actual position value increases but I can feel the ECU is trying to hold the valve fully open. The anti-shudder function of the valve is working correctly, i.e. it does fully close when the engine is switched off.

I believe 100% should be the fully open value so it is almost as though the reported actual position value is displaying as the inverse of the true position. Perhaps this could be confirmed by transposing the + and - wires for the 5v excitation? I've checked the wire colours for the connector against the wiring diagram and they are correct. I will do a continuity check between the connector and the ECU connector just to make sure that I haven't inadvertently crossed the two wires over during the wiring loom repairs.

I cleared the fault codes and none have returned thus far, I will check again tomorrow after driving to work (about 38 miles).

If anyone can offer any suggestions that would be very much appreciated, I am curious as to why there doesn't seem to be an adaption facility for the EGR or IMF / ASV for this particular engine in VCDS. I suppose the ECU will learn anyway?

Many thanks,
Rich
 
   #5  

Uwe

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I believe 100% should be the fully open value
Not necessarily. On many of these sorts of sensors the working range is does not go all the way to zero, or up to 100%. They design then that way so that an open or short circuit (which would likely produce a 0% or 100% reading) is outside the working range and can be detected as a fault. Now I'm not saying I know this is the case on that sensor on your engine, but it is a common way of doing things.

-Uwe-
 
   #6  

DieselDubz

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Thanks Uwe,

Let's day for the sake or argument that the range is 4.5 - 95.5% based on this logic. If the ECU is commanding 95.5 but the position sensor is giving 4.5 that would explain why the ECU is trying to motor the valve fully open (if you push the butterfly towards closed, you can feel it trying to open and it's more force than just the spring).

Watching the measuring blocks whilst doing this, I can see the position value increasing as I manually force the butterfly towards closed position so I'm considering the possibility that the ECU is seeing an inverse position value from the sensor.

I'll do some additional electrical checks today, possibly a bench test with the original IMF / ASV hooked up to a power supply and see whether this might be the case. I had to do a lot of repairs to the loom following the damage caused by the shop who fitted the engine so it's possible I may have made an error and missed it during testing.

Any thoughts on the apparent lack of adaption facility for the EGR and IMF in VCDS?

Thanks a lot,
Rich
 
   #7  

Uwe

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I can see the position value increasing as I manually force the butterfly towards closed position so I'm considering the possibility that the ECU is seeing an inverse position value from the sensor.
Another possibility is that the motor is being driven in the reverse of the expected direction...?

I had to do a lot of repairs to the loom
That makes me wonder if something might be wired bass-ackwards.

-Uwe-
 
   #8  

DieselDubz

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C?ID=525185
That makes me wonder if something might be wired bass-ackwards.
Exactly, there has to be a simple explanation for what's going on. I'll check it out this evening and see if I can find anything.

It's not causing a problem at the moment as the butterfly is staying fully open whenever the engine is running, it will just mean that EGR is less effective as the butterfly won't be restricting the inlet when EGR is scheduled so the draw through the EGR valve will be less than specified.

The butterfly is closing as normal when the anti-shudder function is commanded by the ECU on shutdown so I'm pretty sure the motor is being driven in the correct sense. I'm thinking the position sensor wiring is most likely the issue but should be easy enough to confirm. I did full continuity and insulation tests after completing the loom repairs but it's entirely possible that I missed something, or saw what I expected to see rather than what was really going on.

I ran an autoscan when I arrived at work this morning and there are still no engine related fault codes logged so I'm hoping that once this IMF / ASV issue is resolved, it'll be good to go.

Thanks a lot,
Rich
 
   #9  

DieselDubz

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Just to update on the IMF / ASV issue:

I checked the polarity of the hall sender 5v excitation from the ECU and it is +5v on pin 1 of the valve connector and 0v on pin 3. Pin 2 is the position feedback wire, 4 & 5 are for the motor drive.

I bench tested the old IMF valve with +5v to pin 1 and 0v to pin 3 as per the installed IMF. I monitored the voltage at pin 2 whilst manually operating the butterfly through its full range. The maximum voltage was at the fully open position and was 4.5v. This decreases to 0.5v with the butterfly fully closed.

If the excitation polarity is reversed (0v to pin 1 and +5v to pin 3), the position feedback pin 2 reads 0.4v regardless of the physical position of the butterfly so that rules out incorrect polarity for the hall sender excitation voltage as VCDS can see the butterfly position changing when I manually move it on the IMF valve installed in the vehicle.

It seems to add weight to the theory that the ECU is seeing a false position reading (4.5% is probably the fully closed position) so it is applying power to the motor to try and open the valve, which is what I have noticed when trying to manually close the valve with the key on. The ECU seems able to reverse polarity to the motor as it is definitely operating correctly in the anti-shudder mode, which presumably doesn't depend on position feedback. The butterfly fully closes for around 2 seconds when switching the engine off, as per normal operation.

What doesn't make any sense at this point is that the position % shown in VCDS increases from 4.5% when the butterfly is manually actuated towards the closed position. This seems to be the exact opposite of what should be happening based on the bench test results and so I need to measure the voltage on pin 2 with everything connected and key on so that I can see what the ECU is seeing. If the voltage is increasing as the butterfly is moved towards the closed position, perhaps there is something wrong with the hall sender in the replacement IMF valve (magnet installed backwards or something).

Rich
 
   #10  

DieselDubz

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Another update...

After finding no obvious problem with the wiring for the IMF, I needed to use the vehicle for a few days so I drove as normal but monitored for any engine fault codes on a daily basis.
for over 200 miles everything seemed good and no codes were logged, then the DPF amber light illuminated with "Diesel particle filter instructions" displayed on the MFD and then a few seconds later, the glow plug amber coil light came on, flashing with limp mode triggered.

A scan revealed code P2002 for the DPF and measuring block 075 showed a soot reading of around 45%. G450 differential pressure had also increased to around 15hPa at idle. Ash loading remains at 10 which is 10% of the pre-cleaning ash value.

Looking at block 070, I noticed that there had been several failed passive regens and no successful regens since the DPF was cleaned off-vehicle and reinstalled. I have since attempted service regeneration through the 'Coding II' menu. The code 21295 is accepted and the ECU deactivates limp mode but then fails to increase the fuel delivery to sufficiently raise the exhaust gas temp for a regen to occur. The regen eventually times out and reverts to limp mode.

I have been able to reduce the soot loading slightly by driving at high RPM (3,500) for a prolonged period to increase the exhaust temperature whilst monitoring block 075 but this is not going to fix the problem and obviously isn't a good thing for the engine in the long term. I succeeded in reducing it to 20% but then it quickly increases again when the regen times out and limp mode is activated.

The only fault code logged is P2002 still, if cleared it returns again immediately. I am unsure as to why the ECU won't increase fuel delivery to allow a service regen so I am a little stuck here and obviously have a limited time before the DPF becomes severely clogged with soot unless I continue to operate the engine at high RPM on a daily basis. I've tried following the driving conditions specified for this engine in the RossTech Wiki and also a number of other RPM and speed ranges but with no change to the situation.

Any thoughts or suggestions around the subject would be very much appreciated.

Thanks,
Rich
 
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