Start Control Module (SCU) (3/1): Check

Table showing the key positions that the control module's power supplies are active in respectively passive in.

X=Active

Key position	30-feed	+75 supply accessory	Power supply Ignition on	Crank
0	X
I	X	X
II	X	X	X
III	X		X	X

Conditions 

• Breakout box connected to central electronic module (CEM).
• Or loose Start control module (SCU).

Check 1 

With breakout box connected to central electronic module (CEM):

Measure the voltage on the pins that correspond to the different voltage supplies from the Start control module (SCU) for all key positions, and check that it corresponds with the table that describes in which key position each voltage supply is active.

Check, using Volvo's diagnostic tool, that the key has been approved by the immobilizer.

Check 2 

With loose Start control module (SCU):

Measure the resistance between the control module pins in the different key positions. Compare the result with the table that describes in which position each voltage supply is active. Open switches have a resistance of at least 100 kΩ. Closed switches have a resistance of a maximum of 100 mΩ.