golk MK5 TDi not starting and no Canbus communication

[povetski]

Hi I have a Golf MK5 2.0 TDI (BKD) which I have owned for anumber of years.

A few days ago it failed to start - the engine would fire but immeadiately cut out. I connected it to my VCDS software but I was unable to scan any thing. I did manage to scan the engine which I believe uses and alternative connection. Loads of warnings about communication failures.

Later in the morning I retried the car and it started fine. A day later I went out for a few miles varied driving, stopped the shops all drama free. Next day back to no start.

I read a few things about water ingress and poor earth/grounds so checked all that - everything dry and all ground points look clean and factory fresh.

I swapped out the canbus module (what a pigging nightmare to get at as in this car it is above the clutch pedal). I have done this before when I upgraded to a RCD 310 radio.

The replacement can bus module behaved exactly like the original unit. No comms and engine fired but would not run.

I cant think of anything else to try so if no one on here has any ideas I will get it uplifted to my local independent VAG specialist.

Any ideas?

Many thanks

chris

[Crasher]

The CAN BUS isn’t getting power by the sound of it.

[povetski]

Hi Crasher,

yes I agree that the CAN BUS may not be getting power or is being pulled down by something.

Anyway tried the car again yesterday and it started without a problem. I did a few more checks such as removing the under bonnet fuse box to check for corrosion but that was all as new. Its been running and starting perfectly for the last 2 days so I have cleared all the comms errors and renewed my breakdown insurance.

[povetski]

OK back to square one with this problem. Ran the car every day last week without an issue. Been way for a few days went to start the car and ESP ABS and Steering lights remain on. As before whilst in this state I am unable to scan anything other than the K line items on the engine.

Friday,08,November,2019,15:38:20:48562
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 10 x64
VCDS Version: 19.6.2.0 (x64)
Data version: 20190930 DS308.0
Ross-Tech: Home


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

Address 01: Engine Labels: 03G-906-016-BKD.clb
Control Module Part Number: 03G 906 016 KC HW: 028 101 190 3
Component and/or Version: R4 2,0L EDC 0000SG 9971
Software Coding: 0000072
Work Shop Code: WSC 00417 210 87504
VCID: 6ED9C5917A2AB73F45-5102
6 Faults Found:
17056 - Cylinder 2 Glow Plug Circuit (Q11)
P0672 - 000 - Electrical Fault
Freeze Frame:
RPM: 0 /min
Torque: 182.0 Nm
Speed: 0.0 km/h
Load: 0.0 %
Voltage: 11.93 V
Bin. Bits: 00000100
Temperature: 6.3°C
Bin. Bits: 00110000
18058 - Powertrain Data Bus
P1650 - 000 - Missing Message from Instrument Cluster
Freeze Frame:
RPM: 0 /min
Torque: 202.0 Nm
Speed: 0.0 km/h
Load: 0.0 %
Voltage: 11.10 V
Bin. Bits: 00000100
Torque: 0.0 Nm
Torque: 160.0 Nm
18045 - Powertrain Data Bus
P1637 - 000 - Missing Message from Electric Load Controller
Freeze Frame:
RPM: 0 /min
Torque: 202.0 Nm
Speed: 0.0 km/h
Load: 0.0 %
Voltage: 11.10 V
Bin. Bits: 00000100
Bin. Bits: 00000000
(no units): 0.0
18043 - Powertrain Data Bus
P1635 - 000 - Missing Message from A/C Controller
Freeze Frame:
RPM: 0 /min
Torque: 202.0 Nm
Speed: 0.0 km/h
Load: 0.0 %
Voltage: 11.10 V
Bin. Bits: 00000100
Bin. Bits: 00000000
(no units): 144.0
17978 - Engine Start Blocked by Immobilizer
P1570 - 000 - - MIL ON
Freeze Frame:
RPM: 0 /min
Torque: 202.0 Nm
Speed: 0.0 km/h
Load: 0.0 %
Voltage: 11.02 V
Bin. Bits: 00000100
Bin. Bits: 00000000
(no units): 0.0
29715 - Control Module for Instrument Cluster
U1019 - 000 - Missing Signal for Oil Level/Temperature
Freeze Frame:
RPM: 0 /min
Torque: 198.0 Nm
Speed: 0.0 km/h
Load: 0.0 %
Voltage: 11.48 V
Bin. Bits: 00000100
Bin. Bits: 00000000
(no units): 0.0

Readiness: 0 0 0 0 0

The voltages reported look a bit on the low side. The battery reads 12.3 volts and is a new high spec Bosch unit.

Any opinions on the voltages or anything else see on the scan?



thanks

[tditaff]

Voltage does look low, perhaps you have a parasitic drain...

[povetski]

ISSUE RESOLVED


So I have been living with this intermittent problem on my Golf for many months now. I replaced the ECU with an immobilizer disabled unit so that when the fault occurs the car will still run start and drive. I have kept my Sat Nav handy to use as a speedo when gauges stop working.

A reminder of the problem that I was experiencing was the following:

speedo, Rev counter and temp gauge drop to zero.

ABS ESP lights on

Red steering wheel icon

Airbag light on

engine oil pressure warning with STOP on MFD

Engine fans running full speed.

3 long beeps from the dash

Unable to communicate with VCDS

I had changed a few modules - Dash, can gateway, Central electronics.

The fault was intermittent and the car would behave perfectly for weeks then fault and return to normal for another few weeks.

More recently the problem became more frequent, every time I used the car. I booked it into a local independent VW/Audi expert who was unable to trace the fault but did return the car with it in a permanent fault state. I borrowed a scope and had a look at the waveforms on the can bus which looked fine. If the bus data was OK it had to be the gateway - which was the first item I replaced when the fault occurred!!. I replaced the gateway again but no difference. I made up a test loom so that I could see the power and signals going to the gateway (it's really difficult to get anywhere near the connection for this unit) and swap it easily. The problem turned out be the terminal 30 voltage. This is fed from fuse SB12 in the engine fuse box in my car. The voltage was fine at the fuses but there must be a break in the wire between there and the gateway plug (in fact I measured the continuity of the cable between the fuse and the module and it was open cct.). When I connected a temp 12v supply to the gateway communication was re-established and everything started working again.

I have soldered a wire directly to the can gateway and connected to a terminal 30 supply with a 5a fuse from the internal fuse box. Cleared all the DTC's and all looks good now.

Once you know the issue it all seems so simple but this has been a nightmare problem to resolve particularly as it was so intermittent to start with.


Thanks

Povetski

[VAG-Abound]

Good work.

Depending how tidy you want to make it you can get repair wires that will go into the connector housing, then take that to proper or alternate supply.

[povetski]

If the connector was more accessible I may be tempted to use the repair pins but due to its location I think it will stay as it is. Its a neat repair anyway with the new supply wire fixed securely to the circuit board and brought out through a small hole drilled in the gateway case.

One additional comment about the fault finding was that once I established that the can bus signals looked correct I ran the car with the gateway completely removed and it exhibited exactly the same behaviour. I could only do this as I had the immobiliser disabled in the ECU. Trying to start the car in normal circumstances without the can gateway would have failed because of the immobiliser.

[Rudidudi]

If the connector was more accessible I may be tempted to use the repair pins but due to its location I think it will stay as it is. Its a neat repair anyway with the new supply wire fixed securely to the circuit board and brought out through a small hole drilled in the gateway case.

One additional comment about the fault finding was that once I established that the can bus signals looked correct I ran the car with the gateway completely removed and it exhibited exactly the same behaviour. I could only do this as I had the immobiliser disabled in the ECU. Trying to start the car in normal circumstances without the can gateway would have failed because of the immobiliser.

The problem turned out be the terminal 30 voltage. This is fed from fuse SB12 in the engine fuse box in my car. The voltage was fine at the fuses but there must be a break in the wire between there and the gateway plug (in fact I measured the continuity of the cable between the fuse and the module and it was open cct.).

Is there any wiring or pin diagram to check which wire would connect to ? Is this numbered '30' on the gateway?

[mickeybo]

When using a breakout box is a must when checking canbus out pins 6 & 10 on the 16 pin connector pin 4 chassis ground pin 5 signal signal ground pin 7 k line we came acr0ss this same problem would of been easier using a breakout box