Start Stop Issue - 2015 Leon FR 184 TDI

[ianh89]

Hi,
Not sure if anyone has had similar issues but I was driving home tonight, slowed down for small speed bump in my estate (approx 15mph), and got a message on my dash "Please start engine manually". I dipped the clutch and turned the ignition engine back on.

Around 15 secs later, same thing occured further in my estate.

I assume this is a start stop issue? There weren't any other lights or errors on dash.

Wouldn't like this occuring at a higher speed .

I'm going to take it for another run tomorrow and see how it performs.

I've read a few threads online that it could be a battery issue. My car is a 2015 reg and I have had the car nearly 6yrs, and haven't changed the battery. I don't think it would've been replaced before I had it.

Any advice would be very much appreciated?

Cheers
I

 

[ianh89]

Update :
Started car this morning and Start Stop Error message came straight up, with amber coil light flashing. Car in limp mode.
I've tested the battery voltage and sitting at 12.46VDC, all be it after a journey.

Any advice will be appreciated before it goes into the garage.

 

[BillyCool]

Could be a few things to be honest.

My car effectively stalled a couple of times when at low speed at junctions. Turned out to be a fuel pressure sensor on the fuel rail. Replaced that myself.

Ref the stop/start and coil light - it could be the battery. Mine did that when I had a glow plug issue and got my glow plugs replaced.

I have also replaced the battery - twice! Currently working well.

Might be worth just plugging and unplugging all sensors and check glow plug connections. Then try a new battery.

Are you able to read fault codes? - that might help.

 

[ianh89]

Hi Billy,

Thanks for your response.

Glowplugs could make sense. The car hasn't exactly been running smooth up to this point, and sometimes takes longer to turn engine over on cold mornings. Around a couple of weeks ago, I was travelling along at around 40mph smooth on the accelerator, and the car just momentarily jolted (another thing to add to the mix!).

One of my work colleagues has an OBD scanner, which he plugged in yesterday and pulled up a number of 7 faults without time and date stamps unfortunately, probably due to its limited use. He cleared the faults and I've bought a Carista OBD Scanner and disabled the Start/Stop so that it will never function.

As it happens, after he cleared the fault yesterday and disabled the Start Stop, the car stalled again at low speed last night. I have plugged my Carista in today but no faults are apparent from the stall last night (no coil light or limp mode this time).

The battery life seems to be good at 70% according to Carista.

I'll keep an eye out for any related faults over the next few days and post screenshots of these.

Thanks for your help.

I

 

[BillyCool]

No worries. Happy to help.

Based on what you've said, it could be 2 unrelated issues. My car sometimes has a quick judder when it starts a DPF regen (now you have Carista - get the VAG DPF app and see if the 2 events correlate). The slow to start could be glow plugs and/or battery but there seem to be a host of theories on that. Mine always had a slow/long crank at times and seemed worse in cold weather. Glow plugs and GP relay were changed (and new battery) but it still wasn't perfect. Weirdly, I had an issue recently where the car failed to start due to an apparent flat battery. The AA tried jump pack and jump leads with no joy and said it could be starter motor. I fitted a new starter motor and still no start. Took it to local garage and it started first time off their jump pack! Basically said that there was nothing wrong with it. So, just to be sure they put a new battery in and a new battery earth lead. Since then, it starts perfectly, every time. It's never been that good. Go figure!

The glow plugs should have no impact on stalling at low speed. For me, it was the fuel pressure sensor. I did also have an line performance chip fitted and that plugged into that sensor (one of 3 connection points), so that may have contributed. Since it's had the new sensor and chip removed it's been okay.

70% battery charge means very little. My battery said that and was goosed. I bought a battery tester and checked the charge and CCA. I also bought the like for like Varta 096 AGM battery and it still had the long crank issues. When my garage fitted a new one they put a Varta in it and it's been spot on ever since.

It's such a learning curve!

Been good to see if you get any fault codes come up.

 

[ianh89]

Thanks for the additional advice, will bare in mind for when issue occurs again.

I have also downloaded the VAG DPF app. I read a previous thread which you posted regarding the Carista and VAG DPF app, great bit of kit.

Here is my DPF results from this afternoon. Reading the threads, I take it 31% on the Oil Ash Residue isn't all that bad?

I've performed a Carista scan also earlier, no faults appearing. I'll wait for the issue to reoccur with fault and post my Carista scan here before taking into garage. I'd like to have an active fault on the app to explain my issue to the garage without being fobbed off with "nowt wrong with your car"

Cheers
I

 

[BillyCool]

Looks good to me. You'll see from mine that I'm on 137,000 miles and have 54.2g oil ash residue measured at 68%.

It doesn't mean that it runs fine to 99% then gives up. I will start to get blocked, regen sooner and probably need sorting before that.

Mine regens around 100-120 miles with my shorter 7 miles to and from work but on longer drives I can still get 150-180 miles.

Your hPA pressure is also low, which suggests an unobstructed DPF.