K12 Micra Battery Drain & Central Locking

[Brinzb]

Dear All,
Would like some assistance please.
I have a 2003 Micra K12 with keyless entry.
I noted that after around a week of not driving, the battery goes flat. I have gone through a couple of batteries already. Even if I disconnect the radio, same issue.
Battery health check performed and charging tested, all normal.
Door switches and lights all checked, all fine. Boot lid switch checked and all ok.
I also note that the remote fob locks and unlocks the car (from outside), the car starts fine (key recognised) after brake pedal pressed, however I noted that the door lock switch by the handbrake does not lock or unlock the car doors when sitting inside and doors all closed. You can hear the clicking from the relay in the body control module when the lock / unlock pressed from the button, but nothing from the door actuators. I opened the switch and cleaned the contacts.
Checked the Haynes wiring diagram and cannot find anything suspect in the circuit, apart from the obvious Body Control Module.
I am not sure if there is a fault with the body control module or not? I read some forums stating that the K12 has a common issue with ECU / BCM software. But not sure if this would cause a battery drain and central locking issue.
Any advice is much appreciated.
Thank you.

 

[jls]

It could be. As I understand it from talking to a local nissan dealer recently. The car looks for a registered key quite frequently immediately after shut down but that frequency decreases the more time passes since last finding one. Or at least that's what should happen. Its not a great system even when working to spec and it will drain the battery quite quickly if the car isn't used regularly hence the manual entry suggesting battery disconnection if not going to be used for a month. A week is too quick though so yes it might be the intelligent key system or it could be something else. Have you got a code reader? Does the car throw any codes?

 

[Brinzb]

Thanks for the response. Yes I ran a check with the OBD scanner, no faults.
Ref the central locking, it opens / closes with the fob, however the button inside shows the yellow light on lock, and when pushing lock or unlock, you can hear the relay clicking, but the doors locks do nothing.
The battery drain, hooked a multimeter to test current draw and initially it is high as system powered down after a few mins.
Hence the BCM is one thing that is looking suspicious to me. Just wondering if there is any reliable place in the UK where I can send it for test and possible repair.
Thanks

 

[Micra Paul]

Thanks for the response. Yes I ran a check with the OBD scanner, no faults.
Ref the central locking, it opens / closes with the fob, however the button inside shows the yellow light on lock, and when pushing lock or unlock, you can hear the relay clicking, but the doors locks do nothing.
The battery drain, hooked a multimeter to test current draw and initially it is high as system powered down after a few mins.
Hence the BCM is one thing that is looking suspicious to me. Just wondering if there is any reliable place in the UK where I can send it for test and possible repair.
Thanks

Quote: “The battery drain, hooked a multimeter to test current draw and initially it is high as system powered down after a few mins”.

What are the measured parasitic drain steady figures?

Pull out the ABS fuse & use the multimeter to check for any parasitic power drain when in shut down mode, that is with the ignition off at all times with the ABS FUSE OUT.

Do not turn the ignition on with the ABS fuse out.

Happy hunting

 

[Brinzb]

Thanks for the tips.
The draw is 0.25 amps when doors are locked and then drops to 0.06 amps to 0.07 amps (when red light flashing on dash).
Removed fuses one by one, and realised when the 10A immobiliser fuse is removed, the current drops to 0.02amps and you can hear the BCM relay click. When fuse reinserted, the BCM clicks again and the amps increases back to 0.06 / 0.07.
Thanks

 

[Micra Paul]

Thanks for the tips.
The draw is 0.25 amps when doors are locked and then drops to 0.06 amps to 0.07 amps (when red light flashing on dash).
Removed fuses one by one, and realised when the 10A immobiliser fuse is removed, the current drops to 0.02amps and you can hear the BCM relay click. When fuse reinserted, the BCM clicks again and the amps increases back to 0.06 / 0.07.
Thanks

I had a similar issue 25 years ago with my then W124 series Merc. estate ABS discharging the battery when not used for 5 days or so.

Merc. wanted £2k plus for the ABS module, therefore my optimum economic solution was to pull out its activation relay or the fuse when the vehicle was not going to be used for a few days.

Flat battery problem solved for many years at zero cost.

Improvise, adapt & overcome Job was a goodun.