Cannot lock car with fob

[dewi9uk]

My battery died after leaving the car for three weeks without using it, then having a sharp frost (one or other killed it). Had to buy new battery and then had problems.

 

First problem was fobs did not work. Key would unlock drivers door, could start car and drive it OK, tailgate would not open. Went to local Honda dealer.

 

Dealer recoded fobs(2) and reported problem with tailgate latch switch not operating. Needs new one - £537 fitted !! Bought replacement from breakers, latch worked OK according to dash lights.

 

Fob would then operate doors (unlock only) and tailgate(tourer). However, still could not lock car with fob.

 

Dash tells me that all door switches work correctly (shows doors open/close on display with ign on and doors opened/shut to test).

 

So, where do I go now ? Dealer says locking fault is usually door switches else could be long investigation and possible module/s change job (at gerat expense).

 

Can anyone advise please.

 

[Trevor]

It sounds like the reprogramming did not entirely go to plan.

Now the tailgate issue is resolved then it may be worth going back to the dealer to ask them to re-run the key fob programming to see if that makes a difference.

 

[dewi9uk]

Thanks Trevor. Going back to dealer may involve another £35  ..

 

Have currently got another problem - battery keeps discharging itself over a few days (3 or 4). Looks like about 0.45amp draw with nothing on and car locked.

 

Recharged battery (from 11v) and started pulling fuses. F15 under bonnet cuts draw to zero. Fuse is labelled 'Back Up Acc' in owners book.

 

I am wondering if this is the battery pack in the alarm module, wherever that is hidden. If so then it might not be sending the 'doors locked' signal so fob will operate. Thsi battery might have died due to car battery dying ?

 

Sorry, just a thought at the moment. Will continue research and chasing via WWW.

 

David

[Trevor]

I think I would carry out a deep discharge test on the battery and see if it is up to the mark.
if not, then it won't be able to recover from a discharge (which a healthy battery would). if it is below par then I would replace it with a quality battery.

 

[Charlie]

You've probably sorted it by now, but I had similar problem. My car would draw 250mA when off and locked...I only noticed as I couldn't use it for a few days as I had sent the abs pump off to be fixed. Car only just started, so I looked into it, for me it was the bluetooth/voice control unit circuit board...wasn't shutting off properly for some reason.

Couldn't find a new/used unit for a good price so found the permanent 12v to the board, snipped it and connected to 12v ignition, so only comes on when driving...

 

P.s. the alarm battery backup is inside the alarm itself...

[dewi9uk]

Eventually sorted by changing the window switch unit in drivers door. Apparently has the receiver for the central locking unit inside (??) and now works OK. It has a bit more range also - I can unlock from front door (about 15 feet away).

 

Still draining battery - will look into bluetooth module when I can get at it. It is under the central vent unit by windscreen, correct ? I will then try the mod you suggest as S/H units are around £70 now and come with no guarantee.

 

David

[VanDerSnow]

Easiest way to do is take multimeter and measure the current between terminal and battery while removing fuses one at a time - if removed fuse doesn't change reading in multimeter put it back and try next one. If none of the fuses help it will need more complex digging..

[dewi9uk]

Been a while since I was here last, so I will summarise.

 

Honda HSF/Bluetooth unit proved to be culprit. Found a post suggesting a replacement capacitor could solve problem, so bought capacitor, replaced it and retried. Still draining battery at irregular intervals.

 

I have delved further and MAY have a culprit, but do not have the knowledge to go further.

 

First off, the unit is not just bluetooth, it also handles verbal commands for satnav as well as 'phone (as I understand it). These commands must be digitised and stored somewhere. There is faily big memory chip in the unit which I suspect is used for this purpose.

 

Looking at the datasheet for it (type is Micron 48LC8M16A2) say it is a DRAM (dynamic RAM, which needs refreshing to retain data) and is supposed to swith to 'Self Refresh' mode on power down. This takes little current from the battery. IF it does not do this, and instead goes into 'Auto Refresh', the current is a lot higher - enough to drain the battery over a few weeks of non use.

 

Anyone want to take this line of thought further ?