maybe you have issues with the grounds?

and what about the pods "+" under the hood? dont they getting hot or smth?

you have vcds? any codes from starting button? pins issues? here is smth to look at - you may have "implausible signals" in vcds scan which may be an issue with the wiring / button assuming start from key is always ok, and only the button start has issues.

 

Can you confirm there is no parasitic draw on your vehicle? Is a battery maintainer being used with the vehicle when not in use?. How many days has it been since the new battery was installed with no issues and now it’s happening again?

 

Appreciate the pointers guys.

I drive the car daily. I will take a video showing the sequence required to start the car since this began.

 

After replacing both batteries the car has a new starting issue. If after sitting for a few hours it requires 3 pushes of the console starter button to energize the starter and start the engine;
LOW BATTERY displays briefly in dash display.

Demonstrated here:


If starting after a short shutdown period the starter and engine start normally after 1 push of the center console starter button.
LOW BATTERY displays briefly in dash display.

Demonstrated here:

 

@Randy V ,
Did you do a voltage check and load test on the brand new house battery that you installed, as you still have the low battery warning in white as shown on your dash, that means that the battery is low.
I had this same issue not long ago, purchased a brand battery off the shelf from Advance Auto Parts, took an uber back to the car, only to install and find out it was almost completely dead, took an Uber back and forth again to swap out, and all was good.

Did you scan the vehicle with the Ross-Tech VCDS to see any faults or clear any fault codes to do with the "Battery Charger" at address 71, or addresses 09 Central Electronics, and 46 Central Convenience, wouldn't hurt to check 05 for the KESSY ?

As to your 3 presses of the start/stop button, please try something for me, and possibly video it, as I see you holding the brake pedal down and fully pressing the start button, and it starts, but stalls, that is giving me other thoughts as to an issue, as your second press of the the button is turning the vehicle off, hence the instrument cluster going dark, so those two individual presses of the button are acting exactly as they should, your third press of the button is just starting the cycle of startup all over again, and on this third time, the engine doesn't stall.
So, as I am not at the vehicle this moment, doesn't the start button have two stages of detent, meaning a light press only halfway down to power up the dash and fuel pumps, and then the full press while holding the brake pedal to start, so what happens with a light press, and or no brake pedal, does the dash power up, also, as you grab the driver's side door handle to open, can you hear the fuel pumps prime the fuel system ?

Johnny

 

The first press is not an engine stall, that is the sound of the radio coming on. I turned the radio off after the first starter press. The starter motor ONLY engages after the third press.

I have not had the new AGM battery load tested. It did fully charge when put onto an external battery charger.

 

I'm starting to think the issue is a bad new AGM battery. I'm seeing the battery charger doesn't drop to 0 amps on the charger's meter as is shown on other known good batteries.

Will take it to Costco for a replacement. Not sure if they can do battery load/charge tests there.

I'm still not understanding how a low charged AGM battery would affect starting as the ioher smaller battery (located on right side of US spec CGTs) is the one that is dedicated to the starting function.

 

Hello @Randy V ,
The misunderstanding may be because the thinking is that the right side (starter) battery takes control of the starting function, it does, in a way, BUT, the part to understand is that the starter battery only supplies power to the starter motor/solenoid itself, the starter solenoid (attached to the starter itself) always has the 12 volt power from the starter battery, this 12 volts is always live, the 12 volt power supply to the starter solenoid to engage (trigger) said solenoid, comes from the left side (house) battery circuitry, via push button, ignition switch, kessy, ignition relay, ect.

That's why when you have a dead house battery, but a good starter battery, you still have no power to turn on the ignition, nor start the engine, until you engage the emergency start procedure by turning the ignition key to the left, this would be the same if you had a dead starter battery, and a good house battery, the emergency start procedure would send power via the parallel solenoid by tying both batteries together in parallel, but, because of low power, some functions will not operate, such as push button start, soft close doors, keyless entry, and so on.

Do you have Ross-Tech VCDS ?

Johnny

.

 

I exchanged the AGM house battery for a brand new one at Costco. This replacement appeared to fully charge - better than the previous new AGM battery from Costco.

However, the problem persists. The car sometimes starts on only 1 press of the center console starter button, followed by the LOW BATTERY message in the dash display. If it doesn't start on the 1 push, it always (knock on wood) starts on the 3rd press - sometimes with or without the LOW BATTERY message.

I do not have a Ross-Tech VCDS . I do have a MuCar scanner that has Bentley module. I have used it to reset Airbag warning, Parking Brake fault, and Check Engine faults.

 

Just to close this out -

After clearing codes with the MuCar unit, the car began to start with a single center console starter button press, however I continue to ge the LOW Battery warning message in white text intermittently.

I'm sure the battery is no longer the issue, so I will learn to live with it unless I decide to take it to a Bentley specialist shop for them to take a shot at it.

 

@Randy V ,
what codes you had? Any correlation between codes (clear) and the multi-press issue?

 

No correlating codes. Did have an airbag fault showing the typical rear pax belt arrestor.