VW Passat 2010 2.0 TDI CBDC Non start 008518 Supply voltage

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VW Passat 2010 2.0 TDI CBDC Non start 008518 Supply voltage

Postby scott neal » Thu Feb 08, 2018 12:12 am

008518 - Supply Voltage for Fuel Injector Group A
P2146 - 000 - Open Circuit

Looking for some advice on this one please. The above car cranks, offers to start briefly but then flashes the coil light and stops cranking. It logs the above fault code that clears until you try to start it again. Checks done so far:
All power and ground supplies at ECU present and checked under load.
Checked injector wires from injectors to ECU under load.
All fuses checked.
Resistances of injectors are 180 Kilo ohms (piezo).
Replacement ECU fitted which was sourced off of the internet. A free running ECU that is supposed to be tested and OK but your never sure what your getting unfortunately. It does the same with this fitted, doesn't really rule out an ECU fault.
I've scoped all injectors, voltage and current and compared it to a known good waveform off of the Pico waveform library and what you notice is that injectors 2 and 3 look ok but injectors 1 and 4 have about half the voltage and the current flow looks poor. I'll try to upload the waveforms but I'm struggling to upload them.
My thoughts initially were that the ECU was faulty so we sent it to AC tronics for testing but they couldn't test it. We were then supplied with the free running ECU that the customer sourced as a new unit was out of the customers budget. So do we have the same fault with both ECUs or is there something else causing the fault?
Would it be possible that injectors 1 and 4 are faulty?
Attachments
Volkswagen_Passat_2009_Diesel_20180207-0005.psdata
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Volkswagen_Passat_2009_Diesel_20180207-0004.psdata
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Re: VW Passat 2010 2.0 TDI CBDC Non start 008518 Supply volt

Postby RYM6746 » Thu Feb 08, 2018 9:19 pm

Hi I have seen a VW do exactly this before and it was a shorted injector. The unorthodox way to prove it is to unplug 1 injector at a time and then crank it to see if it runs. You could also plug injector 2 and 3 plugs into 1 and 4 injectors and vice versa and see if the fault code jumps to group B.
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Re: VW Passat 2010 2.0 TDI CBDC Non start 008518 Supply volt

Postby scott neal » Fri Feb 16, 2018 7:19 am

We tried removing each injector in turn but it still refuses to start.
We then removed the glow plugs as a safety precaution to remove compression/combustion just in case and then swapped injector wiring 1 and 2, 3 and 4. The low voltage waveform moved to injectors 2 and 3 so this ruled out the injectors. After reconnecting correctly the car started? We had to pull about at the loom to change the injector loom to different injectors so I can only assume that we have disturbed something in the loom, but why didn't this show up when checking the loom using volt drop when the fault was present? The customer doesn't want to fit a new engine loom so we have made a new injector 1 and 2 wiring loom and fitted it. The car seems fine after an extended test drive.
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