[SaVAGeSoot]

You've cropped out your scan so it doesn't actually show the codes for that controller!

 

[SaVAGeSoot]

Ok, so that says you have flaky power being supplied when the ignition is on. Did you check wiring diagrams to see if any relays are on the circuit? Did you probe or test for power at the plug/controller connection?

 

[SaVAGeSoot]

I suggest you look at wiring diagrams to see what's on that circuit. The error suggests a short in the supply. If there's a relay involved (should be since its key on), check that. If the relay is ok, check wiring with a meter, or check pins at plug for power/ground. Regardless, wiring diagram is required.

 

[SaVAGeSoot]

Your code is suggesting a short... It doesn't say anything about communication/module/coding etc. I simply like starting off with cheap components that can be easily checked with a multimeter, etc before blaming expensive modules.

1 Fault Found:
00185 - Control Circuit; Relay for Supply Voltage Terminal 15
009 - Open or Short to Ground - Intermittent

 

[SaVAGeSoot]

Kessy shouldn't prevent cranking.... It should only step in immediately after it fires and shut things down.... You may have other issues to dig into on top of the fault we are looking at.

 

[SaVAGeSoot]

Read the dual battery SSP. It describes how the system will take something like 4 different approaches when attempting to start a dual battery setup. The main problem is that you've ignored lots of issues/faults and they've now stacked up and you're having to battle them all at once.

If you know you have a draw (handle, whatever) address it. Fix it properly, pull the fuse, unplug the component, etc. You've probably drained/damaged your batteries. Have them tested. Check/inspect starting and charging system,, cables, grounds.

 

[SaVAGeSoot]

Check here, post #3 for SSP mentioned.

dual battery replacement and VCDS coding.

Good morning, I'm new, well relatively new, to the forum. I've been gleaning pre-knowledge for a 2008 Toureg 2 V10 TDI. I work at a firm where one of the partners, who owns this beast, is selling it to me for a ridiculously low sum of money. he is a car enthusiast but illiterate when it comes to...

www.clubtouareg.com

 

[SaVAGeSoot]

You can also monitor your battery specs\condition\state using VCDS.
I don't have a dual setup example to give you, but you can look at mine as a guideline and simply search for the additional MVBs that you would have showing you the 2nd battery metrics.

2014 TDI starter battery replacement - probably...

Well, I've had my '14 since '18, and although it's never not started for me, I did notice it cranking slowly during our winters up here, have had a bunch of codes for low voltage events over the years, have had locks and aux heater codes, and other low voltage hints such as the EMS stepping in...

www.clubtouareg.com

You may also want to log your voltage and your rpm during attempted starts where it cranks but doesn't start.
Many of the ECU maps will have RPM cutoffs, and if a TDI motor doesn't sustain something like 295 rpm or something, the ECU won't fire injectors or will cut off fuel supply or whatever.

 

[SaVAGeSoot]

I'd suggest replacing the terminal 15 relay as your first step, clearing all faults and seeing if the kessy one returns.
Your fault is intermittent, so it could be the relay acting up, on its way out, sticky, etc.