M&S Posted June 26, 2011 Share Posted June 26, 2011 A couple of times recently my TD5 Disco has had a totally flat battery (after been stood for 3-4 days). Now this isn't normal and has only recently started to happen. We figure something was drawing power/stuck on etc and I have swapped relays around, done some tests and all seemed good... ...then the other day I was sat having lunch and I heared the tacograph suddenly start making a noise like a mechanical egg timer going super quick! It normally clicks away quietly but this was really loud and sounded like it was in overdrive! It stopped after I lifted the lid and gave it a slam, but I'm guessing that this is what has been causing the battery drain. Random, and I don't know how long it might have been going on for over the 3-4 days. So, what's wrong with the tacograph and anyone know which circuit it might be fused from? There's no in-line fuse that I can see (taken out some of the centre console) and I can't get the plug off teh back. Well I guess they are "tamper proof" for a reason. PS - no need to go into legalities of them, usage, etc, thanks, as I know this has been covered elsewhere. I don't need or use a tacograph, it came with the vehicle and I decided it a good thing to leave in. Now it needs calibrating and the fault fixing I'drather just switch it off. Another suggestion was the ECU wasn't going into "sleep mode" when teh engine was stopped/vehicle locked. Is this true and if so, any way of checking? Quote Link to comment Share on other sites More sharing options...
Philip Tonkin Posted June 27, 2011 Share Posted June 27, 2011 The ECU sleeping fault is often caused by wifi networks interfering with the alarm circuit keeping it awake. The frequencies for the defender alarm are out side of this range. Quote Link to comment Share on other sites More sharing options...
M&S Posted June 27, 2011 Author Share Posted June 27, 2011 Hmm, no way of fixing that then...is there? Strage how it has just started happening and we have lived in the same street for years Quote Link to comment Share on other sites More sharing options...
western Posted June 27, 2011 Share Posted June 27, 2011 what make of tachograph is it ? might be worth a phone call or e.mail to the makers tech dept. Quote Link to comment Share on other sites More sharing options...
M&S Posted June 28, 2011 Author Share Posted June 28, 2011 It's a lucas. I'll give them a try. Cheers. Quote Link to comment Share on other sites More sharing options...
landroversforever Posted June 28, 2011 Share Posted June 28, 2011 The ECU sleep mode can also not work when the battery in the Key is getting/is flat. How old is the battery in there? Quote Link to comment Share on other sites More sharing options...
M&S Posted June 28, 2011 Author Share Posted June 28, 2011 It's probably 18 months old...funny but it did go through a stage where I thought "must change that" as it wasn't working from as far away. Didn't know that would affect the sleep mode, didn't even realise it had a sleep mode to be honest! Will change keyfob batteries anyway, thanks for the reminder. Quote Link to comment Share on other sites More sharing options...
landroversforever Posted June 28, 2011 Share Posted June 28, 2011 Its what the flat battery on our old D2 was traced back too. It wasn't shutting the car/ECU down properly. Quote Link to comment Share on other sites More sharing options...
M&S Posted June 28, 2011 Author Share Posted June 28, 2011 I wonder if that's why the previous owner said the vehicle battery needed chnaging every two years on these (meaning the D2)...maybe his keyfob was causing problems. Still doesn't explain the tacho going into overdrive but there could be two seperate, unrelated problems. Will try and get a keyfob battery this afternoon. Thanks, you learn something everyday Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 28, 2011 Share Posted June 28, 2011 Not knowing anything about the physical working of tachos but I'm assuming they contain a chunk of electronics to do their job. Anyway some electronic circuits will behave strangely when they aren't being supplied the correct voltage, so could your tachos dance frenzy be explained by reduced voltage from the main battery due to it being drained? Just a thought, as in dancing tachos may merely be a symptom and not a cause. Quote Link to comment Share on other sites More sharing options...
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