Trunk disabled after driving

blaudp79 · Post by **blaudp79** » 27 May 2016, 17:40

Hi,

I'm a newly registered user and this is my first post. I came across a problem that I have not seen discussed anywhere. The symptoms are the following:
I can not open the trunk after the car had been driven. If I wait at least 20-30 minutes, it will open up at the first try and it will open every time until I drive it again. This is what I checked so far:
- The wire harness that most people have problems with is good in my case. One of the wires was pinched half way through, but I have repaired it.
- The switch does not appear to be corroded under the rubber cover.
- Once the trunk opens after waiting half hour it will open every time I push the button, therefore I believe it is not a switch or wire harness issue.
- The car is not stuck in valet mode either.

These are the possible reasons I'm thinking of:

- Maybe it is some sort of custom configuration (e.g: taxi mode, airport limo mode) and maybe there is a hidden switch for opening the trunk as the trunk on these cars can't be opened from inside.
- Maybe the car locks the trunk after the it reaches certain speed, but it fails to unlock once it stops and there is a delay setting that re-enables it.

Has anyone came across something like this?

dp79

Post by **MadeInJapan** » 29 May 2016, 00:26

Welcome to the forum. Sorry, I haven't come across that in my S40... Maybe others will give you an answer to your issue.

blaudp79 · Post by **blaudp79** » 01 Aug 2016, 15:04

Hi everyone,

I had some time to further investigate this, because it is still unresolved and it is driving me crazy.

The latch and micro-switch are both fully functional. It appears to be switching from not working to intermittently working after about 10 min. Maybe as the voltage slightly drops...
By intermittent I mean that it seems that when I press the micro-switch, sometimes I measure the 12V pulse and sometimes nothing. However I always measure 1.5V on the wire that supplies 12 to the latch motor (when the micro-switch is is pressed). Here is a video about it:

https://www.dropbox.com/s/f2d0r6gw05jd7 ... 5.mp4?dl=0

I tried to find out whether this 12V signal that actuates the latch motor is coming through a relay, but I did not find anything online or in the manual. Does anyone know if this signal is directly coming from the CEM or trough a relay?

Thanks

blaudp79 · Post by **blaudp79** » 06 Aug 2016, 12:16

Hi again,

I've done some further research.

1. I have disconnected the battery after I stopped with the car and reconnected it to see if it is software issue. After reconnecting the battery, the trunk still did not open.
2. I have disconnected the battery again and I removed all the connectors from the CEM. I removed all relays and fuses from the CEM case and opened the CEM case up. Inspected the circuit board and I did not find any burnt component and the top of the two capacitors were flat. Reassembled everything and I drove the car again. When I stopped the trunk did not open. After waiting 20 min it opened just like before.
3. I've compared the measured battery voltages. It seems to be the same ~ at both scenarios (when opens vs. when does not)
4. I've taken measurements at each pin of the connectors (switch & latch), see below:

I will update this topic as I know more...

blaudp79 · Post by **blaudp79** » 07 Aug 2016, 15:17

1. I have updated the drawing in the above post. Pin#1 was measuring 11.4V and not Pin#2 (@ 3/35).

2. I have disconnected connectors F and C from the CEM, this way I could look for short circuit in the wire loom. I've measured the resistance between each pin at the trunk end (3/78 & 3/35). I've also checked each pin against ground (chassis). The only two pins that were short to ground were 3/35:3 & 3/78:2. According to the drawing those pins are to be grounded, so the wire loom seems to be OK.

I was looking for other circuits that connect to F:22 and I've found out that Pin#7 of connector 64/48 is also connected to 4/93:D:14 (Keyless Vehicle Module). Since my car does not have this option, I've searched for evidence of a previous installation, hoping to find the source of this issue there. There was no module under the driver seat. I've checked which fuse is for the KVM. It turns out to be F55, which is present in the fuse box (weird, because the manual refers to this as unused slot). I have removed it. I'll drive tomorrow and see what happens....

Post by **abscate** » 29 Sep 2016, 00:31

I think you still have broken wires in that loom. Intermittent stuff like this is a b**** to find