Micky 32

Different car ( Passat) but similar 2.0 TDI engine and the same AGM battery. 6 years and 8 months 190k miles. At 5 degrees C the other morning it just about started. Quite disappointing while other cars are getting 10 years plus out of their batteries. Never abused. It actually began showing signs of it beginning to weaken 3 years ago.

Yep i know that. But I’m fairly sure i have an actual keyless fault. It was happening in warm weather and according to my battery monitor voltages were ok when the fault was happening.

Correct. The readings are quite different with temperature. When it was 20 plus degrees i was getting a reading of about 480 amps and a “ good battery”. When i tested it the other morning at 9 degrees it read 325 amps and “replace”. However the battery is toast because it just about started the other morning so i think it certainly has less than 480 amps. I have a intermittent issue with “ keyless access system faulty”. “engine must be running” only comes up when that fault occurs so it’s related to the keyless fault.. Both faults seem to have disappeared.

No, the car gets good long trips. I have nearly 190,000 miles (2017). I have a battery monitor and the voltage is good. However the first cold morning this year the car just about started. It went into limp mode when it started. The low cranking activated a low fuel rail pressure code.

Yep. Using a topdon. I have been watching it decline over the past 3 years. When the reading drops below 430 amps on a 680 battery it says “ replace “. It has been telling me to replace intermittently over the past 3 years. However during the summer on hot days I miraculously have a “ Good Battery”. i think these testers condemn a battery too soon. They only give you an idea of the batteries health. Results can differ a lot with temperature. My battery is now reading 375-380 amps with a replace message at 15 degrees C . Sometimes the starter does sound sluggish and in cold weather i do get errors beeping on the dash on a cold morning start. The funny thing is for most part the start stop works fine. But last winter it was limited. It worked fine all summer. From my experience AGM’s die a very slow death.

Usually i get a specific message about the air conditioning when cabin temps aren’t met. no, this is new. After 186,000 miles i can’ tell she’s trying to tell me something lol I have a battery tester. It currently is producing 380 amps EN. Battery AGM is rated at 680 amps EN.

No the air conditioning set as I normally have it. To be fair the battery isn’t 100%. 6.5 years old. However when the battery is low i usually get the power consumption is high message, never the engine must be running message. I only ever see that during a regen.

Hi all. An unusual problem the past week. I noticed the start stop isn’t working too well. The message i keep getting is “ engine must be running” The problem is that i only ever see that message when the car is going through a regen. The car isn’t going through a regen. So what could be causing this? If it was the battery wouldn’t i be getting “ power consumption too high”? Or can a bad battery cause the other message also?

My 4wd Passat coupling still ok after 182,000 miles.

I own a 2017 Passat BiTDi running 290bhp all it’s life with 180,000 miles on the clock. Different car but same haldex unit. No issues. I change the oil very 30-40k.

The electronics can be sensitive on these cars. Also remember they are kept at a charge of 80%. Throw in a few stop starts and it’s not surprising a few errors come up. My Passat has the exact same battery(6 years) and for the last 2/3 years i get some low voltage errors . My car started no problem at -7 degrees couple of weeks back. Unless you have low cranking and/or hard morning starts I wouldn’t be too concerned.

Did your battery eventually fail,? My agm battery is now 6 years old. I have a similar tester( Topdon) . I think they are a bit pessimistic on failing a battery. It’s been telling me to replace my battery for the last 2 years and now reads 26% SOH. It’s still started the car no problem recently at -7 degrees. Maybe it’s an AGM thing.

It seems some of the 150’s have an issue with high oil consumption. A friend has a 2017 model with high oil consumption. Destroyed two DPF’s in a short space of time. The burnt oil was clogging the DPF. He had to replace the engine in the end.

A bit healthier than my 680 EN AGM battery just under 6 years . I’m down to 350 EN. after a good drive yesterday my resting voltage after the car fully shutting down was 12.66v. But overnight sitting 11 hours it slowly and gradually dropped to 12.45v. Quite low voltage for an AGM.

How old is the battery? AGM? Mine sounded low this morning too but has done so the last year or two whenever it’s very cold. So far never fails to start. AGM’s don’t usually die suddenly. It’s a long drawn out death with lots of warning.

Seems an interesting charging system on these stop start cars. With the monitor i can tell when the car is in energy recouperation mode. Apparently keeps the battery charged at 80% most of the time. With vcds i was able to find where it shows how many start/stop the starter has gone through in it’s 163,000 miles. A whopping 42,000 ish. AGM’s are tough batteries.

The car gets long drives and rarely has any short journeys so i doubt my battery would need periodic separate charging. My father recently replaced the original battery on his car 14.5 years. That had a life of mostly short runs and never had a charger connected to it. Yeah i use a battery monitor. I can tell by the Open circuit voltage comparisons when the car is in sleep mode with very minimal load on the battery.

i can’t say for sure if it’s reliable. Lower temps does seem to rise it a bit in vcds. But it’s been rising gradually over the last few years. My battery is in the boot. To get the most accurate reading with a tester i leave the boot open and i then lock the car and wait 20 ish minutes for everything to shut down.( boot light turns off)

Did a conductance test on my original 5 years and 10 month old 680A Varta AGM battery. The result is it’s now down to 350A. SOH is 26%. “Replace” The car gets well driven and has clocked 160,000 miles in that time. Amazingly it still starts the diesel engine after a -5 degree night, abeit sounding a little sluggish but it has sounded like that for the last couple of years. However a few symptoms. The start stop works less in the lower temps. The car will cut out at the lights but the engine will re start after about 15 secs with “ power consumption too high” message. Anything above 5 degrees it works flawlessly. If i go into VCDS toolbox i can get the reason why the car restarted after 15 secs “ SOC low” despite driving 40 miles of charging. Other things, errors flash on the dash briefly on a cold morning start. I also get data bus and insufficient voltage codes in VCDS. Once temps are over 6 or 7 degrees start stop works flawlessly and no error codes. According to vcds my battery resistance reads between 7-8 m ohms depending on temperature. I believe a good AGM battery should be 3-4 m ohms. Sorry for the boring post lol

I just replaced the flywheel on my Passat 240bhp ( running 290bhp remapped since new) it lasted 160,000 miles. 80k seems a bit low.

Clutch pack and flywheel.

It’s funny how you get used to a car over the miles. Just got the car back and the difference is quite noticeable. Gear changes way smoother etc even the starter is quieter.

Do you do a lot of motorway driving? That’s 90k more than i have done. Hmmm thinking it’s a bit low now considering i have the same unit ( apart from different diesel vs petrol ratios) as the RS3 and TTRS. Maybe the car being 4wd could be harder on the clutches.

All 2.0 BiTDi 240 passats are fitted with the DQ500 gearbox. The VW dealer claimed they needed replacing through diagnostic .

Yep