A6 Warning Lights

[alex732]

Hi

I have a 2018 A6 diesel

Very intermittently the coolant light comes on for a few seconds on motorway journeys. Seems to be when accelerating, braking or going round sharpish corners at speed. Coolant level is just below max and temp gauge is always constant at 90

Then a couple of week ago the Emission Control Failure light came on. It stayed on for a few days and then went off a couple of days after doing a motorway journey. I assumed it just needed a DPF Regen and it was sorted. However, it then came back on for one day before going off again - and it's been off for a week now.

I have a diagnostics appt booked at a dealer but I'm wondering if it's worth bothering.....for either/both of these issues

Any thoughts welcome

Thanks

[alex732]

Anyone?

[Dr G]

Needs proper diagnosis; your description doesn't appear to be of a common fault.

Had an RS5 recently that did similar with phantom coolant warnings (no codes). A vacuum operated diaphrgam within the water pump was weak. Took a fair bit of finding as there were no symptoms 99% of the time.

[alex732]

Thanks

That's what I thought

What about the DPF? Do you think it's now done regen or could it be something else?

Thanks
Alex

[stevemcs]

Which engine s it ? you may have two issues.

Is it actually losing water ?

[alex732]

it's 2.0 TDI - coolant level pretty constant

[stevemcs]

It’s known for the water pumps to leak, however you would see a drop on the level. If the level is correct and it’s putting the light on I guess a faulty level sensor could cause that

Emissions wise, it could be a box sensor, adblue fault, egr fault, I would get it looked at and go from there.

[alex732]

Thanks - booked in for next week