Hi all, after some advice from the community please. I have a 2014 A4 Avant with the 1.8TFSI engine (170bhp version). For the last few months I’ve been getting an intermittent EML and car going into limp mode. It happens when the car is up to temp and the gap between the two journeys is quite short, eg within 30 minutes so that the car is still warm from before. If I turn the car off and on again the EML goes away and I have full power. 

 

I took the car to my local independent VAG specialist and they have suggested replacing the water pump & thermostat as it comes as one unit, but cost is over £1k all in. There’s no sign of coolant leaking on the pump. Obviously keen not to spend that level on a £4k car but wanted to get advice on repair & cost? Thanks 

Welcome Russell,

To me, I’m finding it very difficult to link the diagnosis to the symptoms! 
Would suggest you consult another trusted independent. 
Does the coolant temperature stay constant at around 90 C and get to that temperature within about 3 miles? 
Regards,

Gareth. 

Yes stays at 90. When the EML comes on, if you stop then restart, that journey also stays at 90. 
 

But on the one occasion the EML came on and we didn’t stop/re-start, it went just above 90 and fans were blowing hard. That’s what made me finally book it in. Error code is P00B700  

 

 

Are there any sensors that can be replaced or are they all part of the water pump?

Like Magnet, I am not convinced the water pump has anything to do with the symptoms.

Before committing to any major expense I suggest you get the battery professionally tested. A failing battery can cause limp mode and false error messages, amongst other problems.

Thanks - it’s had a new battery 6 months ago but it wasn’t coded. That said it must recognise it’s a new battery as the start/stop is now working

Maybe, but lack of coding can lead to the new battery being damaged by the charging circuits so I still suggest you get it tested.

Would I be able to code myself using obdeleven? Local VAG specialist wants £100+ which is a joke and another independent reckons it doesn’t need doing. 

Probably, but there would be no point if the battery is damaged, so get it tested first.

Hi - bumping this topic as my intermittent issue is now all the time. Having done some more online reading and bought an OBDeleven I think it is probably the water pump / thermo unit that needs replacing. The labour cost is 3-4 hours so I’m going to give this a go myself having watched a few youtube videos as it doesn’t look too complicated. Any advice where to get a replacement water pump & thermostat housing? The garage was quoting c.£450 for OEM but price ranges from £100 on eBay to £350 from GSF. Part number is 06L121111P. Any advice from the community please? Thanks 

Edited August 22, 2025Aug 22 by Rust81

Hello Russell,

I could well be wrong, but I cannot see the logic of a generally static running temperature of 90 degrees C with a slight occasional increase ( exactly how much?), being the cause of your issue, so I would move forward very tentatively with this.

Is your OBD capable of monitoring running temperatures? If so, this would be something I would carryout before going to any expense. 
Kind regards,

Gareth. 

It's your money to spend as you want, but I do not believe the problem is temperature related.

Hi, yes OBD can monitor temperatures. I have ordered a replacement G83 coolant temp sensor that plugs into the lower radiator hose in case it’s that and it’s an easy swap. There is one other fault but I don’t think this is causing the P00B700 - Engine Coolant Flow Low/Performance, see attached image. 
 

I also meant to mention that the car normally gets up to temperature very quickly - say within 1 mile and it stays at 90 degrees. Only when the EML comes on and it goes into limp mode and you don’t turn it off and restart does then temp rise above 90. 

Edited August 22, 2025Aug 22 by Rust81

Thanks Russel,

You did mention the principles of your last paragraph, but you are yet to confirm how much above 90 it gets, and whether you have indeed monitored the running temperature via your OBD.

 

Only marginally above 90 I’d say but my wife was driving at the time and all the fans were going flat out when she arrived home after only a 5 min journey. Yes I can monitor the temp via OBD but the EML is now coming on when the car is cold and hasn’t been driven that day. I think it’s probably the thermostat as these are prone to failure on these engines. If I’m replacing the thermo then may as well do the water pump too 

Um. Seems like the thermostat and water are going to be changed then.

I think the thermostat is the logical next step and others with the 00700 error code have done the thermostat and/or water pump. 

We await the outcome then.
Please let us know how you get on. 

Any recommendations for manufacturers/ suppliers if not going OEM? I’ve been looking at Febi or Meyle. The car threw the error again today. After restarting and driving the 1 mile journey home I kept the car running and did a scan. Do these temps look normal to you?

So how long into your journey were these readings taken?

Bit confused by the ‘1 mile journey home’.

This was after a trip to the supermarket. So 1 mile there, 10 min shop and then 1 mile back. Then the code read. 

Insufficient ‘test drive’ distance for any readings to be meaningful. 
Please repeat towards the end of at least a continuous 5 mile run. 

A few new screenshots from this evening. EML came on so turned car off and restarted. Readings were near the end of a c.5 mile journey. Temp gauge in the car steady at 90 degrees throughout. Last screenshot shows a slight increase in temp but not reflected on the dashboard gauge. 

Hi, thought I would provide an update. So I replaced the water pump and decided to replace the expansion bottle whilst I was there as it had to come out anyway to carry out the repair. It’s much easier to see the coolant level now as the bottle is new and not stained. So it’s been two weeks since I replaced the pump and so far so good. No error codes being thrown and the car is taking c.5 mins to get up to temp which is a bit longer than before. So I suspect the issue was with the thermo unit rather than the pump. 

I'm suffering from the same problem. My original 2014 water pump failed - leaking. Had it replaced by an independant and that failed (motor) after about 4 months. They replaced it and ever since it's been flagging  P00B700 - Engine Coolant Flow Low/Performance faults when you drive for a reasonable time (ie engine fully up to temperature), then stop for a short period then go again. After 3 of these it goes into limp home mode. If I reset the fault it clears... They had it back again and flushed the coolant system with a cleaner and found (to my surprise) sand in the system - casting sand from when it was built which we suspect has been dislodged when they vacuum extracted the coolant on the first water pump change. I've subsequently had the coolant system to pieces as the lower radiator hose wasn't getting hot. The car isn't overheating (runs at 90C on the gauge) but that may be just the time of year. There's no coolant flow through the radiator (which passes water without a problem as I've flushed it and got more sand out) I reckon the new pump is either broken or jammed up with sand and I plan to have that out and examine it for blockages and hopefully test it.

So I finally get to my question - does anyone have the pinout/wiring diagram for the 5 pin coolant pump which would the allow me to run it on the bench and see if it's actually jammed or broken - I've read that a jammed pump can break the motor connecting rod/spindle.

Any advice / schematic much appreciated.