Cerbera 1998 - Door Control Unit ignoring switches
Discussion
Hi all - I had the engine tuned last week and my car was returned with the DCU (ME0154) plugs incorrectly positioned - doors and high beam with a mind of their own! - now none of the door/boot switches work.
First, a big shout out to Imran999 for his outstanding earlier post https://www.pistonheads.com/gassing/topic.asp?h=0&... which was the starting point for my investigation.
What works:
1. when the J46 plug was in the J48 slot, a short was created on pin A5 which blew 2 fuses. These have been replaced
2. all 5 battery 12V inputs to the DCU are ok (actually, J46 pin A5 was reading 0.5V which is odd, so I lifted it to 12V by bridging to J47 pin A5)
3. the DCU receives the correct input from the door/boot switches (J47 pins A6-8). When the switches are pressed, the input drops to 0V
4. the RH door actuator reads a small resistance across J47 pins B2-3 (the RH lock drive), so the actuator is probably still breathing
What does not work:
4. the DCU is holding J45 pin B3 (the alarm input) at 12v - it thinks the alarm is alarmed and therefore ignores all 5 door/boot switch inputs.
What I've tried (without success):
5. grounding the alarm input to 0V (J45 pin B3) by cutting the pink wire and attaching the alarm input to the earthing point in the boot
6. pulling all the plugs out of my Meta M99T alarm control box
TIA
First, a big shout out to Imran999 for his outstanding earlier post https://www.pistonheads.com/gassing/topic.asp?h=0&... which was the starting point for my investigation.
What works:
1. when the J46 plug was in the J48 slot, a short was created on pin A5 which blew 2 fuses. These have been replaced
2. all 5 battery 12V inputs to the DCU are ok (actually, J46 pin A5 was reading 0.5V which is odd, so I lifted it to 12V by bridging to J47 pin A5)
3. the DCU receives the correct input from the door/boot switches (J47 pins A6-8). When the switches are pressed, the input drops to 0V
4. the RH door actuator reads a small resistance across J47 pins B2-3 (the RH lock drive), so the actuator is probably still breathing
What does not work:
4. the DCU is holding J45 pin B3 (the alarm input) at 12v - it thinks the alarm is alarmed and therefore ignores all 5 door/boot switch inputs.
What I've tried (without success):
5. grounding the alarm input to 0V (J45 pin B3) by cutting the pink wire and attaching the alarm input to the earthing point in the boot
6. pulling all the plugs out of my Meta M99T alarm control box
TIA
Pretty sure your DCU box will be borked. It's an easy mistake to make as the plugs aren't Poke-Yoke.
I'm sure someone with experience of doing this will be along to offer more insightful advice.
Pop the box open and photo the boards, the failure may be obvious.
Jody @ Python Racing is very skilled in this area.
I'm sure someone with experience of doing this will be along to offer more insightful advice.
Pop the box open and photo the boards, the failure may be obvious.
Jody @ Python Racing is very skilled in this area.
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