Checking Fuses And Power Supply

The phone module (PHM) is powered via a fuse from the central electronic module (CEM).

Check whether the fuse for the phone module (PHM) is half burned by testing using a new fuse.

HINT: A half burned fuse can cause intermittent faults. 

Check the power supply to the phone module (PHM) by:

• measuring the voltage between phone module (PHM) connector A terminals #5 (#5) and A #6 (#6)
• measure the battery voltage.

The fault is in the power supply cable if the difference between the power supply for the control module and battery voltage is greater than 2.5 V.

There may be an internal fault in the phone module (PHM) if the difference is less than 2.5 V.

Remedy as necessary.

Other information: 

• see SIGNAL SPECIFICATION
• see CONNECTING THE BREAKOUT BOX
• see LOCATION OF COMPONENTS
• see PHONE MODULE (PHM), REPLACING (2006-2010)
• see CHECKING WIRING AND TERMINALS

Fig 2: Identifying Connector (F) Terminals

Courtesy of VOLVO CARS CORPORATION

See: VERIFICATION