Glow plug light flashing
I have a 2010 Audi A3 2.0 TDI (140) Sport Sportback with the engine code CF, which I have owned for just over four years. It has done 55,000 miles and I service it every year with new filters, etc, despite the low mileage (though I don’t usually use it for runs of less than about eight miles or so). I also run it on super-grade diesel.
It’s a lovely car, but I have an intermittent problem with the EML glowplug light flashing. It first happened about a year ago at the end of a 50-mile journey, when the car went into ‘limp-home’ mode. However, on the next start, it was working perfectly. It next happened a few weeks ago, but on this occasion it may have been due to me trying to pull from too low revs in fourth gear. This week, it has happened on two successive days after sitting in traffic queues. On the second occasion, I switched off at the next red light and restarted the car to clear the fault.
According to my Foxwell NT500 VAG scanner, the fault code triggered on all these occasions is ‘P040300 Exhaust Gas Recirculation Circuit – Passive/sporadic’. I have had a look around the engine bay and the vacuum hoses and cables all seem to be in good health, although it took me a while to locate the EGR valve as it is combined with the EGR cooler on this engine and positioned down the back of the engine on the exhaust side. If it was located at the front on the inlet side, I would take out the EGR valve and clean or replace it, as I did with my son’s A4, but I believe the setup on this engine is more awkward, requiring the removal of the front of the exhaust, draining the coolant, etc.
My thought is that the EGR valve is getting clogged up and intermittently generating these faults and needs either cleaning or replacing. Do you think I am on the right track or is there something else I should look for? Chris Humphreys
The engine code on your Audi should be four digits and the CFF is probably followed by an A or B. With the fault code you have, the EGR valve certainly appears to be the source of the problem. My first recommendation would be to check the connections and cables for chafing – as you have already done this, hopefully we can assume all is OK. It would also be worth checking the wiring harness, as they have a tendency to fill with water, which can cause problems.
Provided you are happy that there are no problems with the electrical supply or connections, then the EGR valve itself is the most likely culprit. It may be possible to clean the valve, but with a suggested 4.5-hour time to remove and refit the unit, this is not a quick or easy task.