Locking issue 2001 v70 2.4 n /a

ashleyg82v702001 · Post by **ashleyg82v702001** » 15 Jan 2021, 05:36

Hello, me again......

I have a locking issue on my front passenger door and my rear drivers side door..

Front door issue;
Upon locking the lock drops then immediately pops up again, thus unlocking. However the deadlocks drop 20 seconds or so later and the pass door secures on deadlock with the button in the u lock position.
REM: Fault code (signal too low).

Rear door (intermittent issue) ; secures fine no problems until I close the boot having accessed via the boot release button on remote (leaving rest of car locked) it fully unlocks the back door. You see the back door unlock as the boot hatch lands.
REM : Fault code also low signal.

Can anyone shed any light on this? It has had a new REM fixing another fault this is continuing so I'm very doubtful it is a module fault.

Post by **firstv70volvo** » 15 Jan 2021, 21:24

ashleyg82v702001 wrote: ↑15 Jan 2021, 05:36 Hello, me again......

I have a locking issue on my front passenger door and my rear drivers side door..

Front door issue;
Upon locking the lock drops then immediately pops up again, thus unlocking. However the deadlocks drop 20 seconds or so later and the pass door secures on deadlock with the button in the u lock position.
REM: Fault code (signal too low).

Rear door (intermittent issue) ; secures fine no problems until I close the boot having accessed via the boot release button on remote (leaving rest of car locked) it fully unlocks the back door. You see the back door unlock as the boot hatch lands.
REM : Fault code also low signal.

Can anyone shed any light on this? It has had a new REM fixing another fault this is continuing so I'm very doubtful it is a module fault.

You might have more than one problem so some questions to help see if this is the case.

For the front door issue, is this a repeatable problem, does it happen every time you try to lock it? It immediately pops up again?
I'm not sure I understand the deadlocks, you're saying the front door locks after about 20 seconds and it's lock but the lock button remains up in the unlock position, is this correct?
Is your car a RHD car? Is so this means it's the left front door?

For the rear door problem does it ever unlock when the rear hatch door isn't being closed? Just wondering if the problem only occurs with the tailgate door is closed? When you have the rear door lock problem is the front door lock also acting up at the same time?

Do you notice any locking problem differences using the key fob vs. using the inside door locking switch? The reason I ask this is I had a problem one of the rear locks and the key FOB would lock/unlock all the locks except the bad lock wouldn't lock but the inside door lock button would lock all the locks but wouldn't unlock any of the locks so the bad lock created a difference in how the key FOB and inside door lock button worked.

I've look at the wiring diagram and I can't yet figure out how what's going on, the CEM controls all the locks but the REM controls the rear door lock relays.

Did you have these same exact problems before the REM was replaced?

ashleyg82v702001 · Post by **ashleyg82v702001** » 15 Jan 2021, 21:40

The problems are erratic on the front pass door sometimes it locks sometimes it doesn't using the ddm button and the fob button. I've tried grease incase it was a sticky mechanism no difference.
The rear door only does it 1/5 - 1/10 times can go a month without unlocking when boot is closed then does it everyother time for a few days then sorts itself out again for a week or 2 only doing it sy once in that time...
It's really quite bizarre.
I've always had this issue since buying in June.
I replaced the REM just before Christmas and problem persists, all relays work they were swapped about when I did the REM. (no problems moved if that makes sense)

As I said the error codes are 'door unlocked signal low'

ashleyg82v702001 · Post by **ashleyg82v702001** » 16 Jan 2021, 03:06

OK so it seems this ghost

is not uncommon just affects in different ways... I can't see a resolved case though

I'm going to see if it's some form of calibration issue, by trying this reset process...
Will post my results

ashleyg82v702001 · Post by **ashleyg82v702001** » 16 Jan 2021, 09:15

Can't seem to calibrate it. Anyone know how the door knows it's shut? Is it through the latch itself? I know the sensors all work as the door open warning cancels when all doors are shut. But, it seems like the lock thinks the door is open... (does that make sense) if I lock with any other door open ALL the locks immediately spring back to the unlocked possition... Time to throw money at it and try a new door catch do you think?

Post by **firstv70volvo** » 16 Jan 2021, 10:29

For the front lock it sounds to me like it's the lock assembly itself, the door lock/unlock switch. There are two sliding switches in the door locks (see photo) and I'm assuming one switch is to tell the CEM the latch is locked or unlocked and the other switch is for the door being closed or open. The door "signal low" error is likely the one switch being low when it's expected to be high. This could be a problem with the lock assembly or possibly a wiring problem (intermittent short to ground) but I'd suspect the lock assy first. Unfortunately you can't easily open up the lock assembly for repair. I've had to replace a front door lock assembly for a similar switch problem and a rear door lock for a broken linkage piece.

I'd start with the front door lock and replace the lock assembly with a new or salvage part.

This a photo of a rear lock but your front lock will also have these sliding switches
[attachment=1]V70 Rear Door Lock Assembly001.jpg[/attachment

ashleyg82v702001 · Post by **ashleyg82v702001** » 16 Jan 2021, 11:20

Thankyou I'll explore when the weather improves a little

Post by **firstv70volvo** » 16 Jan 2021, 14:08

ashleyg82v702001 wrote: ↑16 Jan 2021, 11:20 Thankyou I'll explore when the weather improves a little

I looked at the old lock I have and confirmed one switch is lock/unlock and the other switch is the door open/closed switch.

For the lock switch it's 0 ohms when the lock is locked and and for the door switch and when closed it's 0 ohms. From the symptoms you're describing it sounds like the door closed switch may have an intermittent open when it should be closed or 0 ohms at all times when the door is closed.

: InkedV70 Rear Door Lock Assembly001_LI.jpg (1.95 MiB) Viewed 1050 times

ashleyg82v702001 · Post by **ashleyg82v702001** » 16 Jan 2021, 14:44

So perhaps some electrical contract cleaner may be the solution

I'll test and see

Post by **firstv70volvo** » 16 Jan 2021, 19:30

ashleyg82v702001 wrote: ↑16 Jan 2021, 14:44 So perhaps some electrical contract cleaner may be the solution I'll test and see

You're not going to be able to get to these switches with contact cleaner, they're inside the sealed housing. The pictures I've attached is after I've cut open the housing and removed the switches from the circuit board. I removed the switches from the circuit board and you can see how the contact fingers slide on strip traces to open or close the switch. It might be possible to drill holes through the housing in the exact location and depth to spray cleaning fluid into this area.