Cranking but won't start

**Gazza243** · 10-07-2022,11:40 AM

Thanks I will check that, I'm guessing it's in the fuse box in the engine bay

**Gazza243** · 12-07-2022,10:31 AM

So managed to get vagcom and got a couple of fault codes that my autocom didn't pick up. Can't seem to post a picture but the fault codes are:
18058
18045
18043
They all seem to relate to missing information from the power control module but from looking around it looks like they ja e to be coded to the car. Is there anything to to check on there or anything I'm missing like a common fault in a ground wire or something before I go down the rabbit hole of replacing that module?

**Crasher** · 12-07-2022,01:02 PM

18043 (P1635) - Powertrain Data Bus: Missing Message from A/C Controller

18045 (P1637) - Powertrain Data Bus: Missing Message from Electric Load Controller

18058 (P1650) - Powertrain Data Bus: Missing Message from Instrument Cluster

We need to see that in controller context. Do a full scan, save it and post it including the VIN.

**Gazza243** · 12-07-2022,01:08 PM

Car battery is currently on charge as it has now gone flat, but full scan shows exactly what you just posted

**Gazza243** · 13-07-2022,04:06 PM

Update on situation, still won't start lol.
Charged battery and now getting same codes with an extra one
17978 - engine start blocked by immobiliser.
Tried to sca instrument cluster and immobiliser but it seems only module that scans in vcds is the engine module.
Been trying to check all electrics everywhere for any breaks etc but to be honest not sure where to look except fuses and relays which all seem good
Please help 🤣

**Gazza243** · 13-07-2022,07:05 PM

After further investigation I guess the canbus is down which is why no module connects and is using kline for engine codes. My next step will be checking the gateway module and wiring around it just so I can get a better scan for the diagnostics.
If anyone has any more suggestions it would be greatly appreciated.

**VAG-Abound** · 13-07-2022,07:47 PM

I'd ask on the Ross Tech forum for pointers on diagnosing CAN bus problems.

I'd also take a look at the gateway module as you say. Some pins on it that might help. In the absence of other help once I knew it was powered OK I'd unplug each bus in turn to see if the others come back to life. if so then a damaged module may be flooding / locking the bus(es). I'd expect some of the VCDS type cables could also log raw CAN traffic which might give a hint what is or isn't trying to talk.

1, 2 & 14: 12V when ignition on
11 & 12: Ground
5 & 15: Convenience CAN
6 & 16: Drive train CAN bus
8 & 18: Dash CAN bus
9 & 19: OBD socket CAN connection
10 & 20: Infotainment CAN

**Gazza243** · 13-07-2022,07:56 PM

That information is going to be an excellent help thank you, I was going into it blind tomorrow but now I know the pins that's going to help a lot.
I'll update tomorrow once I've checked
Thanks again

**VAG-Abound** · 13-07-2022,08:02 PM

Do you have somewhere else you can test the VCDS cable?

BTW, all the CAN wires should it orange plus a trace colour. If that doesn't match above pins then don't rely on them

**Gazza243** · 13-07-2022,08:17 PM

Unfortunately not it's my first and only vag car, the lead is a genuine rosstech one I borrowed it off a mechanic friend of mine and I have the latest vcds.
Hopefully I won't have too many modules and wires as it's a very basic car