Strange wires from CD unit M90A

C-NUMB · 21 July 2012, 20:30

When checking the choke solenoid today, noted 2 dead end wires coming out of the cd unit. Black with yellow stripes (B/W). Here the diagram. CD unit is number 2 on the picture page 99.
According to that 2 B/W wires comes out of the CD unit but are connected together(?) Well, mine are not(just loose) but engine runs fine?

Anyone here have any ideas what is the function of those two wires and why they shold be connected? If following the diagram I should connect those two(i guess) but on the other hand, maybe not before knowing the function....

C-NUMB · 22 July 2012, 09:23

Think I have the explanation for the B/Y wires. Found following on the web:
"This wire is short with a pull apart connector that comes out of and goes back into the CDI unit. If you pull apart the connector to open the connection it will disable all the engine safety functions and you can test if the engine will run over half speed for a short time"

So if You want to have the alarm/safety features in operation, better keep them connected.

Pikey Dave · 22 July 2012, 10:27

I wonder if it's part of a stop circuit. E.g, if the ECU/EMM gets a fault, say overheat, it shuts down the CD unit. The 2 wires you have could be to override this for fault finding. Opening them would have no affect until the engine had a fault & tried to shut down or go into "limp" mode, which it wouldn't be able to do if the wires were open. Just a thought.

C-NUMB · 22 July 2012, 12:04

Quote:

Originally Posted by Pikey Dave

I wonder if it's part of a stop circuit. E.g, if the ECU/EMM gets a fault, say overheat, it shuts down the CD unit. The 2 wires you have could be to override this for fault finding. Opening them would have no affect until the engine had a fault & tried to shut down or go into "limp" mode, which it wouldn't be able to do if the wires were open. Just a thought.

I guess this is the case. Think will buy the factory service manual used or new, it seams to be pretty simple engine probably, possible to fix most things basis "DIY"