If someone was to buy a second-hand A2 with its needles out of calibration, and thus ran out of fuel, needlessly replaced the thermostat/temp sensor, got a speeding fine, etc, I would empathise with their irritation. The 'buyer beware' principle would protect any private seller, but traders could find themselves in a really difficult position, with no understanding of the source of the problem or how to fix it.
Five days ago, an A2 rolled up at Timmus Towers for some electrical diagnostic work. The owner had bought the car only a few weeks ago. The issue was reported to me as follows: "My engine never gets up to temperature and the fuel gauge never reads full, even after filling the tank to the brim. I've had the thermostat, the temperature sensor and the fuel level sensor changed, but it's not made any difference. The garage are totally confused and have given up on the issue."
Given my words of caution earlier in this thread, we all know why I'm making this post in this thread.
In the photo below...
I'm asking the rev' counter to show me 3000rpm. OK, that's not too bad. I've seen worse calibrations from factory.
I'm asking the temperature gauge to show me 90 degrees. That's not good; it's 9 degrees out of calibration.
I'm asking the fuel gauge to show me half a tank. That's not good; it's 8 litres out of calibration.
I'm asking the speedo to show me 62mph. That's not good; it's 6mph out of calibration.
It didn't take me long to find the cause of the problems, but the immediate question was "why has this been meddled with!?"
I removed the instrument cluster and found that all the warning LEDs had been snapped off the instrument cluster motherboard. Although I see this regularly on FSI clusters, this is the first time I'd ever seen a TDI cluster having been vandalised in this way. Of course, to remove the warning LEDs, the needles and scales had to be removed. Whoever did this clearly didn't have the ability to recalibrate the needles, so just stuck them back on and hoped for the best.
The fuel gauge is out of calibration in the 'safe' direction. The driver will believe the car is about to run out of fuel long before the fuel tank is empty. However, the temperature gauge and the speedo are out of calibration in the 'unsafe' direction. The owner of the car drove to my place via the M6, sitting nicely at 70mph ...except they were actually doing 76mph. They had wondered why they were going so much faster than the rest of the motorway traffic. Had the temperature gauge ever reached 90 degrees, the owner may have concluded that the underlying issue had finally resolved itself ...except the engine would actually have been overheating.
Potential speeding tickets and cooked engines aside, the owner had needlessly spent a considerable amount of money trying to resolve these issues. It highlights that correct calibration of the needles is vital.
To be honest, I was amazed by the sheer coincidence of what was in front of me. Only days earlier, this issue had been discussed on A2OC.
Of course, I repaired the motherboard, recalibrated the needles and everything was back to normal. Cruise control was also added, but that's a more regular occurrence.
Cheers,
Tom