Passat 3C springt bei niedriger Außentemperatur schlecht an | Posts 16+

Okay, then I'll try using the battery from the trunk. Or would that one need to be replaced as well? As I said, I got a new battery in July, but only for the front!

Dieselmartin, please also review my questions above under EDIT - THANK YOU .

Hm,

The battery from the rear is not a standard starter battery - I would rather take one from another TDI (that's why the sisters also drive a 3C ).

Removing the starter motor... if it spins faster afterward, you've definitely gained something.

The tachometer illumination will be switched off above a certain voltage level.
This is merely a rough indication that "someone is drawing a lot of power here, which isn't readily available." "My car also always turns off in the morning."

"The speed may seem the same," but that's precisely the point.
If it's running at speed X, nothing happens; it could run like that for hours.
If it's running too rich, it's injected and then eventually it won't run on electricity anymore, but on diesel.
X seems to be around 200, and I've heard that it also depends on the temperature.

One could "tune it out" .

I wanted to build you a BMR starter log today, but I ended up driving the BLS .

It was only 2 degrees Celsius.
But I still think it's awesome how the BLS still starts up even with almost 140,000 kilometers.

m;

..and it still does, even with 240,000 km , at least the ASZ is still performing well despite the battery being over nine years old...


Battery in the trunk. That suggests a heater and a lot of electrical components. How are they wired? Does the battery in the trunk only power comfort features? If so, replacing it wouldn't make sense for your symptoms. You said the front battery is practically new. What do the cables leading to the starter look like, and what are the connections?

Quote:

You said that the front battery is practically new. What do the cables

leading to the starter look like, and what are the connections ?

Perhaps try charging the battery overnight and then see what happens when it's fully charged.

Or how it starts with a jump start in the first attempt.

Please pay attention to the potential differences depending on whether the center of mass is placed on the block or on the battery.

If the engine starts with a jump start using a jump start cable connected to the battery, but not when connected directly to the battery, then you have proven a grounding problem.
The positive cable is not so easy to test.

m;

Okay, earlier I found some time to check the grounding points, etc., in the direction of the starter motor. I didn't completely remove the starter motor itself, because one of the mounting screws seems to be only accessible from underneath, and I don't have a lift. So, the grounding points were a bit corroded, but I've seen it much worse before. Nevertheless, I sanded the contact surfaces verschandeln with sandpaper and a file, applied copper paste to everything (to prevent further corrosion), and reassembled it.
I also disconnected, cleaned, and reattached the positive connection on the starter motor once. You can see pictures of the initial state in the attachment!

Okay, so I swapped my front battery with one from a Golf 5 2.0 TDI, installing it in the same orientation. The Golf started without any problems before, and it also started fine with my battery. My Passat didn't show any noticeable changes either (but it's also warm right now). Okay, I'm going to use the Golf battery for a while, and he's going to use mine - we'll be swapping them daily .

The rear battery in my Passat definitely powers the interior fan and the heater unit of the auxiliary heater. However, I don't know whether it's normally charged from the Lima or whether it's connected to the solar roof.

I might also try giving it a jump start. Would it also work to connect a second battery using jump cables, or would a power pack be sufficient? Because it would certainly be easier to deal with than having to drive a second car over to provide a jump start .

Okay,

Let's see what the new battery says tomorrow, after being at 2 degrees for 2 days and with a little VCDS tweaking.

m;

I still maintain that the second battery will only have a minor impact on this: the circuit diagram is what ensures safety here.

Here's a tip for future action: Always implement only one measure at a time and then observe the results. If it's working perfectly now, you don't know if it's because of cleaning the contacts or the battery .

I'm also getting feedback from the Golf 5 TDI, which is now using my battery, and so far it's working perfectly fine. If this continues to be the case after the next cold snap, I'll put the battery back in my Passat. That way, I can still provide a definitive judgment about the cause.

Unfortunately, I have to put further research and feedback regarding success and failure on hold for the time being, as we are currently experiencing almost springtime-like temperatures outdoors .

Good evening, everyone.
I hope you all got through Christmas well .
While the temperatures are currently relatively mild for this time of year, I had further reason to investigate this topic again during the holidays. Thanks to the holidays, my car had been sitting for a bit longer than usual, and it was now barely starting. Unfortunately, I hadn't connected my VCDS for logging because I wasn't at home with the car.
Following that, and thanks to the suggestions I found here in this thread, I had the idea to take some measurements regarding the quiescent current.
I measured a clamp-on voltage of 12.37 V earlier, after approximately 11 hours of operation. Is this value already too low?
Right after that, I measured the quiescent current. It continuously decreased from just over 2 amps and stabilized at a value of 0.14-0.21 amps after approximately 15-20 minutes. Since I only have a multimeter available, I couldn't determine an exact average value, and unfortunately, I couldn't record any data. Does anyone happen to have any comparable values from a Passat 3C? I was only able to test one Golf 4 earlier, and it had a constant idle current of just 0.01 amps after less than 5 minutes.

Thank you .

Hello Alphagolf.

Unfortunately, I can't provide you with any values for a Passat. The 10 mA reading from the golf course is plausible.

Just wait until the vehicle enters its idle state.
Connect the multimeter and then remove each fuse, one by one. If the quiescent current drops when you remove a specific fuse, you've found the component that's drawing more current than it should. At least, this would help narrow down the issue.

"In my Lupo TDI, I measured 22 mA of quiescent current after 3 minutes, despite the active rodent repellent system being engaged. After 17 hours, the battery voltage is 12.92 volts." Battery is 3 years old.

I find the 140-210 mA quiescent current to be too high.



Best regards,
Martin.

If I search, I find something

/viewtopic.php?t=25782&highlight=idle current
/viewtopic.php?t=25861&highlight=idle current

alphagolf wrote:

I was only able to measure on a Golf 4 earlier, and it had a constant idle current of 0.01 Amperes after less than 5 minutes.

However, that was a model that largely lacked a CAN-Bus. Because mine also takes over 45 minutes to completely shut down.
Please wait longer before taking the measurement! 20 minutes is far too short for vehicles like these.

VW says "2 hours".

And most importantly: Lock the hood and the vehicle.
So, let's lock the hood.

But then again, before letting the hood fall, unlock .

m;

On my Passat 3C: definitely less than 50mA.

If I remember correctly, it was at 25mA, with occasional spikes up to 40mA. VW specifies a limit of 40 or 50mA in the workshop documentation.

So, your 140-210mA is definitely too much.

However, the framework conditions mentioned by Martin are important. Until then, your measurements will not tell you much.

Greetings.
Guste.