Checking contact resistance, oxidation and wiring

Check the handset and keypad unit / carphone module connectors for loose connections according to Loose connections (terminals) .

Check the wiring between handset terminal #E6 and keypad unit / carphone module terminal #A4 for a short-circuit to ground according to Short-circuit to ground, intermittent faults .

Remedy as necessary.

Other information: 

• To access and replace the handset, see Handset holder
• To access and replace the keypad unit and/or carphone module, see Radio/carphone, replacing
• To connect the breakout box, see Connecting the breakout box, Carphone module
• For information about signals and connectors, see Keypad unit /Carphone control module (PHM) (for hands-free loudspeaker and handset) and Handset (for keypad unit / carphone module (PHM)) .

Fig 1: Identifying Breakout Box

Courtesy of VOLVO CARS OF NORTH AMERICA.

Fig 2: Identifying Ohmmeter

Courtesy of VOLVO CARS OF NORTH AMERICA.