I have had an ongoing problem for 2 years with my 2018 Kodiaq .2.0l TSI battery losing charge over a few days and the battery charging randomly at different charge rates.

To date I have had:

2 replacement batteries (at my cost)

then under Extended Warranty (now expired)

1 replacement negative battery lead (with sensor)

1 replacement alternator

Symptoms (monitored with Ancel Battery Manager device and multimeter)

Battery discharges in a few hours from 100% SoC /12.8v to around 65% then continues slowly after that over several days

Charging when driving starts at 14.3v but even when battery is low quickly drops and does not get to full charge even after half an hour of driving

Static current too high warning now showing on ODBII monitor but dealer had the car for a week and did not find any fault

Also shows "DAB aerial short circuit to earth" warning

I need to gather more evidence to persuade dealer to pursue. All suggestion welcome!

A friend has a new Kodiaq VRS petrol with identical symptoms. Is this a known issue?

It sounds as if you may have a parasitic drain issue, is your infotainment system original?

Can be a bit of a lengthy process of elimination to find which module is not going into sleep mode.

The voltage variation you mention is normal - the smart alternator is designed to do this to allow for energy recuperation under deceleration and/or braking.

@andrewclark55 Have you resolved this problem with battery discharge?

Sorry @Warrior193. I did not get any notifications of replies - again!

No, the problem is not resolved but still working on diagnostics after dealer had the car for six days and could not find any fault. But I now have two clear DTCs.

B110311 Digital Radio antenna 1 Short Circuit to ground

U40600 Static current too high (this one is intermittent)

With the help of ChatGPT (which can now even correctly interpret photos!) I am homing in on the aerial fault as it might be stopping the car from sleeping as I believe the shark fin aerial has an amplifier.

But Having taken down the rear section of headliner I have been unable to disconnect the blue FAKRA connector. Anyone know how to release it? I will upload a photo.

Not sure on the Kodiak but on my Octavia there are two antennas. FM one on roof and DAB one in rear side window. These connectors I think need pushing in and at the same time release tab. and then pull out. Always have trouble with them.

Alasdair

From the little I have been able to see online, there should be a release tab on the exposed end of the jack, beneath the metal cable crimp - that needs to be pressed-in to allow the jack to release. That might be just below the 'whitish' section shown in your 2nd and 3rd images.

Hi Guys

Once again did not get any notifications of your replies. I don't know why that is.

I finally got the Fakro connector off by sliding the white piece downwards and tested that the DTC is still there after clearing and leaving the cable disconnected. So not an aerial fault, leaving cable or head unit fault. Resistance measurement shield to Earth is 140 ohms and there is 5v on the core to earth.

I am presently not seeing any significant parasitic drain so rather than attempt to get at the Amundsen head unit I will run with it for a while and see if it returns.

Thanks for all contributions to date.

To clarify - was the connector you removed for testing the one on the Shark Fin (GPS) or the one for the DAB antenna on the side window?

I have had this on 2 vehicles to date, my Kodiaq cooling fans were running constantly due to a faulty fan relay. You could hear the fans running so it was obvious there was something wrong as they never switched off - flattened the battery. New relay - all fixed.

The other was on a C-class Merc and was not visible/audible at all. The diesel (!!!) Mercs were fitted with a pre-heat element that, on ignition, would begin to warm the engine ahead of actual starting. Very useful if you park your C-class in the very cold parts of the world. My pre-heater had gone faulty, and so was running all the time - result was a flat a battery every night. Pre-heater was disconnected, all 'fixed'....

May give you food for thought?

1 hour ago, Sallyday10 said:

I have had this on 2 vehicles to date, my Kodiaq cooling fans were running constantly due to a faulty fan relay. You could hear the fans running so it was obvious there was something wrong as they never switched off - flattened the battery. New relay - all fixed.

The other was on a C-class Merc and was not visible/audible at all. The diesel (!!!) Mercs were fitted with a pre-heat element that, on ignition, would begin to warm the engine ahead of actual starting. Very useful if you park your C-class in the very cold parts of the world. My pre-heater had gone faulty, and so was running all the time - result was a flat a battery every night. Pre-heater was disconnected, all 'fixed'....

May give you food for thought?

I presume you mean the glow plugs on the Merc?

Edited 2 July2 Jul by Warrior193
correction

1 hour ago, Warrior193 said:

I presume you mean the glow plugs on the Merc?

Cars for Nordic markets are usually equipped with ceramic heating elements, helps to warm up the engine very quickly.

15 hours ago, Warrior193 said:

I presume you mean the glow plugs on the Merc?

No, an additional heating element to work up the engine prior to starting.