2011A3 1.6tdi limp home mode

[MattRoll]

I have a 2011 A3 1.6 tdi manual gearbox which has done 83k miles. About a year ago it started going in to limp home mode after a long drive of over an hour. The engine management warning light came on and a flashing yellow coil warning light also lit on the dash. If I stopped the engine and restarted it the flashing yellow coil disappeared and limp home mode disappeared and the car drove fine again for a few minutes until the same thing happened again - limp home mode and the same 2 warning lights on the dash. I took it to Audi Dundee main dealership and they told me it was showing an error code indicating that 2 glow plugs had failed. I pointed out that there were no starting issues with the car and that I couldn’t understand why failed glow plugs would cause the car to go in to limp home mode after driving it for 90 minutes. The Audi technician agreed with me but told me that the glow plug error code could be hiding a more serious error code and recommended replacing the glow plugs. So I paid £200 to have the glow plugs replaced. Since then I have only driven short distances over 30 minutes and have had no issues. However at the weekend I had to drive almost 400 miles down to England and after driving for around 90 minutes the same warning lights lit on the dash and the car went in to limp home mode. I drove the rest of the way down to England in limp home mode. The car obviously felt down on power and didn’t like going up hills but otherwise the engine felt smooth and otherwise okay. The same thing happened on the journey home to Scotland. I should also mention that in the last 3 weeks when I start the car first thing in the morning, having driven it the previous day, it starts but struggles to idle, won’t rev, coughs and splutters then stalls. This doesn’t happen every time I start it in the morning but seems to be happening more frequently now and is also getting worse to the point where it can take 20 attempts to start it with stalling and restart until it eventually runs. It’s still running smooth with no lumpiness, and good power until limp home mode after 90 minutes driving. I also wonder if there’s an element of something overheating as limp home mode seems to kick in a bit sooner on a hot day and if you drive the car gently at lower speed it takes longer for limp home mode to kick in. I have replaced the lambda sensor about 6 months ago and this has made no difference. There’s clearly an issue with initial starting - it’s like there’s an airlock in the fuel line. Then after driving around 90 minutes there’s the limp home mode problem. Are these 2 problems related??? Could it be the auxiliary cooling pump for the exhaust gas recirculating valve that’s failed causing intermittent limp home mode after a longer drive? If so would this also cause the issue at startup? Thanks in advance for your comments

 

[MattRoll]

Update, it was the exhaust gas recirculation valve that was failing causing limp home mode to kick in. I understand you can get an ECU remap which “deletes” the egr valve but the car still passes MOT emissions tests. Only costs £149. ….. and save yourself £1k………