Golf 1.6 TDI start problem

[basil31]

morning,
writing this on behalf of a friend.
he has a 2011 Golf 1.6 TDI.
Had a replacement EGR valve 2 years back. Ran into problems with the replacement, and the garage were a bit dodgy, and then couldn't afford to do any more, so the car sat for nearly 2 years with nothing done to it.
He has now found we might be able to tweek the EGR settings on VCDS/Vagcom to make it run better. i have vcds so was looking to do that.
Battery was completely dead, so he has replaced the battery with a decent Yuasa stop/start type.
There is power throughout the vehicle, but the problems we have are as follows:

1. radio was initially locked last night - we wondered if that might have interfered with the immobiliser somehow (see below). after waiting the hour, the radio is now unlocked and the same issues remain.
2. on ignition the car starts for 1 second, then cuts out, then only engages the start motor.
he has tried both keys, and new battery in one key, so assume its not key related.

i assume that as the car starts okay and runs for 1 second, there is adequate fuel. We can hear the fuel pump whirl okay.
does this sound like imobiliser related - starts then cuts out, or fuel pump/filter?
all fuses are okay. unable to check relays.

3. have tried to plug in VCDS and a normal code reader. Power to both devices, but neither will "connect" to the car and will not read - like the car won't talk to it. Both devices will work on my car, so its not a software/hardware issue on the readers.
I know laptops have a small battery in the motherboard to retain certain bios settings. Does a car ECU have anything similar which might have run out during the 2 years of no running/battery?

so in short...car will not communicate via OBDII port despite powering the devices, and engine cuts out after 1 second running.

Car is 10 miles away from so i won't be able to reply quickly, and probably only get back to it over the next few days.

thanks in advance.

[Keithuk]

Is your radio an OEM? All OEM radios code is stored in the ecu. If you disconnect the battery for some reason, when you reconnect it checks the radio code to see if it still matches.

Is your VCDS a genuine cable or a cheap Chinese cloned cable?

If you do a full AutoScan that will check the immobiliser. The vehicle will start for a second or two then stop, the immobiliser warning light will be on in the dash. I'm not aware there is a CMOS battery in the ecu to retain any previous settings like a computer. When you reconnect the battery and drive it around it will find the basic settings.

[basil31]

Hi Keith, thanks for the reply.
Yes, radio is original OEM and is now unlocked and works.
Yes, VCDS cable is genuine - cost me around £250 and i have previously had Ross-Tech support when i used it on my Skoda. It worked fine on my 2015 Superb and 2005 A6. its just not reading anything from the golf, even though the green light is powered on. The other scanner i used was an Autel generic scanner - it took power from the OBDII port, but would not "connect" or take any data.
Unfortunately as it cuts out after 1 second, and not able to get codes, we're unable to drive it anywhere.

[Crasher]

No you can't alter the EGR settings with VCDS, that was only on the much earlier distributor pump injection engines. The EGR is probably acting up because they fitted and aftermarket one from Euro Car parts and they are useless, one failed on me immediately. The start and immediate cut out show the immobiliser is triggering, are you sure the battery is good? Does the dash power up?

[basil31]

thanks for the detailed reply.
not sure what new EGR was fitted - my friend has doubts they even replaced all of it as the garage suddenly got dismissive when questioned what was done. i've not yet looked myself to see if aftermarket or VW - expect it was probably aftermarket as he was on a budget at the time. i'll get him to check the paperwork.

i wondered if it was the immobiliser kicking in as it is getting fuel and goes for 1 second, but then dies - and then just the starter motor sounds - like the electrical signal for fuel/ignition has been cut. would a dodgy EGR value give a symptom of the immobiliser kicking in then?

yes, battery is brand new yuasa. i wondered if it needed coding - like i had to do on my audi a6 recently, but as i'm unable to communicate with either the VCDS or Autel reader, i cannot do anything.
all dash screens light up, and act as you would expect when starting the car normally. radio and lights all function as normal.
starter motor sounds good - no issue with weak battery.

just problem with the car communicating with the VCDS and Autel reader.

[philipharmes]

It does sound like the immobiliser, but you shoud be getting a warning on the dash.
Double check he has the correct keys.

A lot can happen to an unused car in 2 years including mice/ rats chewing through wiring, building nests in air filter & trunking.

The fact that it runs for a second suggests there is not too much wrong with the engine.

I would disconnect the inlet hose as close to the engine as possible so you can be sure it is getting air ok.

Possibly also block the EGR ( just in case it is stuck fully open ) just as a temporary measure to see if the engine will run.

[Keithuk]

You don't need the engine running to do an AutoScan. If it is a genuine VCDS cable and you have registered it online VCDS Dongle Registration

You can join the Ross-Tech forum and make a new thread about your problem, with a full AutoScan attached. There are more experts on there.

Has it had the VW emissions update?

[basil31]

You don't need the engine running to do an AutoScan. If it is a genuine VCDS cable and you have registered it online VCDS Dongle Registration

You can join the Ross-Tech forum and make a new thread about your problem, with a full AutoScan attached. There are more experts on there.

Has it had the VW emissions update?

not sure on the VW emissions update - i think so, but couldn't swear to it.
i assumed it was a problem with the car rather than the scanners as both the VCDS and the Autel scanner wouldn't communicate despite taking power from the car, plus both work okay on my audi.
i'll start a thread on the ross-tech forum and see what they suggest - they were very helpful when i had an issue with my last skoda when i had an issue with the auto cruise control. might be a few days before i can get back to the car and take down word for word what the VCDS said - it was trying to initiate, but timed out after a few attempts.
i couldn't work out which fuse was for the OBDii port - as i was wondering if there was an issue with that - as VW in their wisdom don't put a list of the fuses in either the fusebox or the book and was tricky to track down online with a phone outside in the dark at 2'c.

[Crasher]

So you cannot access any controllers in the car? A full autoscan gives nothing? If so it sounds like water has leaked onto the CAN BUS unit which is under a plastic cover below the wiper motor.

[basil31]

So you cannot access any controllers in the car? A full autoscan gives nothing? If so it sounds like water has leaked onto the CAN BUS unit which is under a plastic cover below the wiper motor.

Correct, no controllers will respond to either my vcds or another scanner. There is power, but it will not tale any readings.
thanks for the tip, I’ll see if we can have a look at the CAN BUS unit for water ingress.
my mate has just checked all fuses and all are okay.