PHB

To change the knock sensor apparently means removing the water pump and thermostat module, which I only had replaced earlier this year at the cost of £900. To replace the knock sensor will cost about £400. However the garage managed to clean the sensor terminals and since then I have not had any faults.

Garage have just come back and said it could be a faulty knock sensor or a wiring issue to the sensor.

Sad to say the problem is occurring nearly every time I accelerate up to 70 mph, unfortunately the fault does not stay on when I take it to the garage. They have taken advise but made no progress if finding the fault. I really like the car but I can't carry on with this issue as it can put me in difficult situations, I think it will have to go.

Thanks Steve. Just returned from the garage and as expected there were not fault codes found. The garage are going to forward the problem onto the tech people but without a fault code they said they do not know where to start.

I am getting a warning "engine speed governing" displaying on my screen. It states I must not increase the revs above 2500rpm. It frequently occurs when I am accelerating which is a problem as I lose power, it is as if the speed limiter has come in. This started after I had the water pump and thermostat changed which the garage does not believe would be an issue and the garage can not find any fault codes. In the manual it stated this is to stop the engine overheating but the temperature is normal and sometimes the engine is cold as I have only traveled a few miles. Has anyone got any ideas what could cause this fault.

I am getting a warning "engine speed governing" displaying on my screen. It states I must not increase the revs above 2500rpm. It frequently occurs when I am accelerating which is a problem as I lose power, it is as if the speed limiter has come in. This started after I had the water pump and thermostat changed which the garage does not believe would be an issue and the garage can not find any fault codes. In the manual it stated this is to stop the engine overheating but the temperature is normal and sometimes the engine is cold as I have only traveled a few miles. Has anyone got any ideas what could cause this fault.

Had it fully checked out and it has been confirmed as the thermostat and water pump. I spoke to Audi UK head office and they said they are not aware of any issues with these parts or the extended warranty in the US and Canada, they look after the UK only!! I have had a few similar issues on this car and although it's a great car to drive I think it is going to be my last Audi.

Had a price from an independent for a new thermostat housing and water pump at £950 inc VAT, is that a reasonable price? I also contacted Audi main dealer from where I purchased the car and asked about the extended warranty that is in the US and they said they would come back to me. In true Audi fashion they they have not.

I completed a 210 mile journey this week and lost half the coolant reservoir and there was a damp area near the water pump. At the end of my return journey 210 mile, no coolant was lost, very confused. However I think I am going to get the water pump replaced as this appears to be a poor area on these cars. Not however a cheap job.

Hi Gareth. Reading it again it looks as if the extended warranty only applies to the US, I assume someone has taken Audi to court over the failure. You would have thought if it was good for the US it should be honored for all Audi A4. I will continue to inquire and give you feedback later. Regards Peter

I have just read an article on another website that suggests that there is an extended 8 year warranty on the water pump and thermostat on this car as it is a known area to leak. I can't be certain that mine in leaking from there but there is some damp in the area. Is anyone aware of a warranty.

Hi Gareth. I carried out the test you suggested, I drove 9 miles and then kept the revs up at 2000 for 3-4 minutes. The ambient temperature was about 10 degrees and the coolant temp was at 90 degrees and there was noticeable white condensation type smoke but with am ambient temp of 10 degrees would I not expect that? You mentioned additional tests, what did you have in mind? Kind regards Peter

So I assume, although it is the passengers side wing mirror, it could be the wiring in the drivers side and possible more likely as the drivers door is used far more than the passengers side.

Thanks Gareth, as you say, when, we get a dry day I will carry out the test. The area around the reservoir cap is dusty and perfectly dry, but yes I will purchase a new cap. The car has only done 40K miles and I really enjoy driving it, so I hope I can resolve the problem.

I understand there has been a post on this subject in the past but there does not appear to be any conclusions. I am losing coolant, about half a lire in 150 miles. The system has been pressure testing but the pressure held and there is no signs of any leaks. The garage suggested that it could be an issue with the head gasket with water finding it's way into the exhaust. They suggested if this is the problem then it my be the time to sell the car (not a main dealer). Has anyone had this problem and found the fault.

Could the change in voltage be caused by a bad connection on the wiring loom. I am assuming the door control module is OK as the drivers door mirror heats up fully.

The heater is working intermittently, I have replaced the glass with not change. The power to the mirror changes from 14 volts to 4.6 volts. The diver's side is working perfectly. Any ideas?

My fault was intermittent but I did not hesitate and changed the sensor which resolved all faults.

Thanks I have had mine changed about 18 months ago but with little confidence with the car I am going to carry a spare.

.any thanks, will have a look.

Where did you find a sensor for £10, the best price on ebay I found was £69.

Sorry to hear you have had this problem, your response from Audi is typical, even if you contact head office they are not interested and don't except it is a known fault.

For the price of a sensor buy one and fit it yourself, there is a video early in this post which shows how easy it is.

Unfortunately several of us had a similar response from Audi, they said they do not have the time to look at all the forums and said the best thing we can do is take out their extended warranty and then we will not have a problem. I think they forget about the safety issue when this fails, my car was very difficult to drive when I got the message. This is my third Audi but sadly my last.

It's important that you contact Audi UK and report your situation as in the past they claim they are not aware of any issues with the sensor. The detail of who to contact can be found on this forum in an earlier post.