Start/Stop system fault

@hellodave

No, new thermostat is working flawlessly, don't worry.

Make sure they bleed the system and top it up, otherwise coolant level will drop and you'll get a warning.
 
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If the car is plugged into the Audi diagnostics it should run the engine and coolant pumps in a specific way to eliminate air locks..
 
hellodave said:
Sorry for bringing back a thread from the dead but this happened to my 2017 S4 today - 12K miles, fan running on full from engine start, start stop fault, temp a notch above normal and check engine light on.

I called Audi Assist who diagnosed a bad thermostat and had it recovered to the dealer. I await their verdict on Monday!

It seems this is a common fault but the Audi bulletin still states it is "under investigation" i.e. "we still don't know what causes it". It advises dealers to take photos of the bad thermostat and seals before returning the faulty parts to them.

Has anyone had the fault reoccur after having it fixed?
Click to expand...

Interesting to see all these similar stories. I had the same problem on my March 2017 S4 last June. It took a while to get the parts to fix it, as it seemed the problem was quite a new one then. Anyway, it re-occurred last week and the car is back at the dealers. Pretty annoyed that this failure has now happened once per year. Its my first Audi and I love it, but doesn't fill me with confidence about keeping it when the warranty runs out next year.
 
Long time lurker, first time poster.
My S4 has today suffered the same issue. Dec 2017 build with 12k miles.
 
gromit2468 said:
Interesting to see all these similar stories. I had the same problem on my March 2017 S4 last June. It took a while to get the parts to fix it, as it seemed the problem was quite a new one then. Anyway, it re-occurred last week and the car is back at the dealers. Pretty annoyed that this failure has now happened once per year. Its my first Audi and I love it, but doesn't fill me with confidence about keeping it when the warranty runs out next year.
Click to expand...

Yes it has happened twice on mine now. First in October last year and then again a few weeks ago. They have replaced the thermostat for a second time. They claim it has been redesigned now but I’m not sure I believe them.
 
You can add me to the list....

Car suffered same symptoms and is now with Audi for suspected thermostat failure.

Audi S4 MY18- Build week 22 of 2018. 5700 miles and driven since August.
 
Add mine to the list, seems to stop the fans going full chat if I pull over and turn the engine off for 20 seconds then resume journey. Oil temp gauge returns to 90 as well then. Audi want the car back in two weeks for the thermostat.
 
Add mine to the list. Jan 18 registered car, 24k miles.
Symptoms, EML on, fans run at 100% from cold. Water temp shows 100c (normally 90c) and Oil temp barely if ever gets above 60c (normally 85-95c) Also it doesn’t do a “cold start” idle like it normally does holding the revs around 1200 for a few seconds, instead, it goes straight to 800rpm and splutters a touch until it stabilises without the warmup enrichment. Gearbox shifting also seems to be a little rougher.

Here’s the pertinent bits of a VCDS as an incase it helps anyone in the future:


Code: 
Address 01: Engine (J623-CWGD)       Labels:. 07K-907-309-V1.clb
   Part No SW: 8W0 907 559 G    HW: 06M 907 309 D
   Component: 3.0l V6 TFSI  H22 0008 
   Revision: B2H22000   
   Coding: 0A2A00322526050B34080000000000000000000000000000
   Shop #: WSC 06324 790 00001
   ASAM Dataset: EV_ECM30TFS0118W0907559G 001011
   ROD: EV_ECM30TFS0118W0907559G.rod
   VCID: 49CEAB3079361C0F5D7-801C

3 Faults Found:
33160 - Engine Coolant Temperature Sensor 3
          P01E4 00 [237] - Implausible Signal
          MIL ON - Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 39272 km
                    Date: 2019.09.20
                    Time: 14:09:53

                    Engine speed: 1255.50 /min
                    Normed load value: 3.1 %
                    Vehicle speed: 120 km/h
                    Coolant temperature: 56 °C
                    Intake air temperature: 30 °C
                    Ambient air pressure: 1010 mbar
                    Voltage terminal 30: 12.940 V
                    Unlearning counter according OBD: 40
                    Engine status: COENG_RUNNING
                    Engine status-Test_Program_Co Eng st COMPU VERB UBYTE: 3

30226 - Engine Temperature too Low
          P3081 00 [237] - -
          MIL ON - Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 39271 km
                    Date: 2019.09.20
                    Time: 14:09:26

                    Engine speed: 1857.00 /min
                    Normed load value: 17.6 %
                    Vehicle speed: 117 km/h
                    Coolant temperature: 58 °C
                    Intake air temperature: 29 °C
                    Ambient air pressure: 1010 mbar
                    Voltage terminal 30: 12.860 V
                    Unlearning counter according OBD: 40
                    Engine status: COENG_RUNNING
                    Engine status-Test_Program_Co Eng st COMPU VERB UBYTE: 3

11786 - Sensor for Cylinder Head Temperature
          P017B 00 [237] - Implausible Signal
          MIL ON - Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 39271 km
                    Date: 2019.09.20
                    Time: 14:09:22

                    Engine speed: 1890.50 /min
                    Normed load value: 16.5 %
                    Vehicle speed: 120 km/h
                    Coolant temperature: 58 °C
                    Intake air temperature: 28 °C
                    Ambient air pressure: 1010 mbar
                    Voltage terminal 30: 12.860 V
                    Unlearning counter according OBD: 40
                    Engine status: COENG_RUNNING
                    Engine status-Test_Program_Co Eng st COMPU VERB UBYTE: 3

Readiness: 0000 0000

Dealer still has mine waiting a thermostat to arrive from Germany tomorrow.
 
OK really ****** now. Just under 12 months and the fault has returned ... all the same symptoms and have to wait for Audi Assistance to come out tomorrow morning so that the dealer will book me a hire car. This is the third thermostat failure in 2.5 years .... seriously worried about what I’ll do when the warranty runs out in March.
 
Peter Huggon said:
OK really ****** now. Just under 12 months and the fault has returned ... all the same symptoms and have to wait for Audi Assistance to come out tomorrow morning so that the dealer will book me a hire car. This is the third thermostat failure in 2.5 years .... seriously worried about what I’ll do when the warranty runs out in March.
Click to expand...

Extend your warranty
 
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Is that expensive (silly question I guess)?


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Same thing started happening on my 2018 S5 last night. There idle sounds rough and fans sound odd. Then the warning light came up and the start stop feature disabled message.

called my dealer this morning. They can’t fit me in till next Friday and if I want a loaner then I would need to wait a month!

It’s my first Audi and not exactly the premier dealership experience I was hoping for.
 
Stephen Saunders said:
Same thing started happening on my 2018 S5 last night. There idle sounds rough and fans sound odd. Then the warning light came up and the start stop feature disabled message.

called my dealer this morning. They can’t fit me in till next Friday and if I want a loaner then I would need to wait a month!

It’s my first Audi and not exactly the premier dealership experience I was hoping for.
Click to expand...

Use Audi assist, instant loan car and you jump the queue. Just be firm on the phone you are concerned about driving it because of the noise
 
Audi assist have been round. It was the thermostat. The guy used to work for Audi and knew what it was straight away. Said it’s very common.

The service centre at my local Audi is shut now so it’s going on a wagon Monday morning.

just waiting for a hire car to be dropped off (Golf)
 
Good news they are sorting it out quickly. I’m my experience it is the same with all makes, prestige or not, if something effects you driving the car and you need it fixing quickly with a loan car it is better to call the breakdown service.
 
Just make sure they bleed the system before delivery back to you, mine was not bled and I had to top it up at home. Disgraceful.
 
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2015 Audi TT happened to my car yesterday stop start system fault appeared to also effect the performance booked in for tomorrow fingers crossed
 
Hi All, I recently got this on my A6 - 2017. 18K on the clock. Starting the car from cold last week it attempted to start, then stopped, Mirrors opened, closes, When pushing the Start/Stop button again I got the system fault error and the car reluctantly started. However this weekend the car was parked having driven for 15mins or so - noticed the fan was going even after the car was off (it's done that a few times, been told this is normal) so didn't think much of it. Returned to the car approx 4 hours later, when pressing the start/stop no error- engine would tick over, just a click. All electrics were working so didn't think it was the battery, though someone offered a jump start and it worked. Has been working since but not sure what happened there? is the battery draining? could the fan have killed the battery?
 
Same problem with me but different symptoms.

Temp will not rise at all, heaters hardly blowing warm (-2 this morning, before anyone says anything), stop start error..

Audi VW chap arrives within 40 minutes :icon thumright: and confirms what I already knew. Car booked in tomorrow as I'm a key worker.

S4 Avant first reg Jan 2018 with 10,114 miles on it, poor show Audi
 
audi upgrades
SiPie said:
Same problem with me but different symptoms.

Temp will not rise at all, heaters hardly blowing warm (-2 this morning, before anyone says anything), stop start error..

Audi VW chap arrives within 40 minutes :icon thumright: and confirms what I already knew. Car booked in tomorrow as I'm a key worker.

S4 Avant first reg Jan 2018 with 10,114 miles on it, poor show Audi
Click to expand...

However, on gentle journey home, temp eventually up to notch above 90 and fans on all the time. Heh ho
 
SiPie said:
However, on gentle journey home, temp eventually up to notch above 90 and fans on all the time. Heh ho
Click to expand...

Service manager chap actually admitting all that has been said here. Thermostat housing in S models around that age not up to job and has been superseded with a reworked part. Unusual for them to admit that it’s a problem.
Not so good to see my perfectly cleaned interior wiped down with about a gallon of anti bacterial spray. Understandable though.
 
Hi guys just had exact same fault start stop fault, temp at 100c fan and fan full blast, I scanned for faults myself and this was faults, cleared faults drove car for a bit all OK, then wife drove car and it happened again, car now in highland audi inverness cars a 2018 b9 s4
8666618f8fe462336befdede480a759e.jpg


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Been a while since I've posted on here. I had this issue about 13 months ago and as everyone is saying say it is a faulty thermostat. However the bad news is just this morning the issue has come back :(.

Car is out of warranty and have spoken to Audi and they are trying to say that the new part is not covered by warranty and I'll have to pay to fix it! Clearly I'm not accepting this answer but be aware the issue with thermostat may come back so if you can extend your warranty go for it. I'm taking it to my local ( Not Audi) garage on Monday to get the faults checked.

Audi Edinburgh could not see me until the 8th of December and wanted to charge me £60 to check the fault, they also needed the car for the full day and due to Covid I'm not aloud to wait at the garage.

Audi 2017 B9 S4 Avant.
 
After getting a replacement thermostat in 2019 the same symptoms have come back today - temp one notch over normal, fans running full and start/stop fault on dash. Not happy!
 
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Update on my car, I decided to get it fixed at my local garage ( not Edinburgh Audi) as the whole process was just easier and cheaper. Audi did offer me a good will gesture which was 60% of the time and part paid for. However even with that it was going to end up taking longer and cost more than my local option.

The repair took 4 hours + the cost of the part, be aware though that the start/stop fault code directs technicians to replace the smaller thermostat on the camshaft. Audi wanted the car for 2 full days.

Dam thing should not break anyway!
 
It’s frustrating that it keeps failing and when replaced isn’t covered by warranty for the new part. My 17 plate car has had 3 thermostats in 4 years and was one of the main reasons for extending the warranty. This is a fundamental design flaw that Audi has made no effort to correct.
 
My 16 plate RS6 c7 has just started to display this fault on start up now. Noticed a couple of mornings last week that after my 7 mile drive to work that the fans were running when i turned the engine off?. The warning has only just started to this week however?.
I took an independent warranty out on the car when i purchased it which i hope will cover this if it's the same thermostat fault.
 
Think I have the same fault 2017 S4 B9 20k miles came up on Sunday stop start fault limp mode 3500rpm. Switched off engine to clear but temp reached 97C on dash. Haven’t needed to drive it since then but reading this thread it’s seems clear what the problem is, wondering whether best to drive to dealership which is next to petrol station car needs fuel anyway, or call Audi assistance? ( I have the roadside assistance not Audi insurance) was wondering if I can get a loan car? Also have extended warranty, not full parts cover the next level down. Advice appreciated Cheers
 
Reading above suggests Audi assist route, will try that!


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Mine still runs/drives fine, just the warning on start up. Booked into the dealership i got car from this Thursday & i've spoken to the warranty company & most things should be covered.
 
Hi all, this has just come up on my 2018 S5 which is a month out of warranty. As it appears to be a known issue which Audi 'are investigating' I will push for a contribution but does anyone happen to know what a new thermostat and install costs?
Thanks
 
Mine was in for the fix 3 weeks ago & it was just a software update & no parts required. Perfect now & the stop/start works again as it should. Wasn't covered by the warranty i got from the dealer (specialist not a main dealer) but they were great & booked the car in through them selves so it was done at cost price to me which was just over £100.00. Would have been just over £200.00 with out .
 
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