I had the dreaded sub tank warning light problem on my 2003 GU 3ltr. I read 25 pages and found plenty of suggestions BUT non seemed to be the same problem as mine.
I had hit the jackpot! not only did I have the sub light on, I also had the hand break and the battery warning light on.
Nothing seemed to have been posted about this. Having checked ALL the suggested cures, I had read, I found an unrelated comment about the alternator output giving false warnings. I checked mine and sure enough, it was only producing 11.6 V Anything less than 13.8would cause all sorts of problems although it would still produce enough power to charge the battery and start every time.
I replaced the alternator and sure enough problem solvered!!.
The article also warned NOT to increase the the output size. I had a 90 amp but there are also 100 and 110 amp units as well. If you increase the output it warns you that it will not be recognised by the computer and can also damage it.
I did not have to do any other alterations.
Hope this helps those who have this problem.
Reply With Quote
