Checking the cable

NOTE: Applies only to car phones with Volvo On Call.

Fig 1: Identifying Ignition OFF

Courtesy of VOLVO CARS OF NORTH AMERICA.

Ignition off
Disconnect the battery negative terminal
Disconnect central electronic module (CEM) connector D, phone module (PHM) connector A and the supplemental restraint system module (SRS) connector
Ignition on
Connect the battery negative terminal.
CAUTION: There must not be anyone inside the passenger compartment when the battery is connected.

The collision cable runs from the SRS control module to the car phone module (PHM) and the central electronic module (CEM). If the cable is defective, there is a risk that the safety measures in the central electronic module (CEM) and the emergency call from the car phone module (PHM) will fail if the airbag system is activated.

Checking for short-circuits to ground

Check the collision sensor cable. Check for a short-circuit to ground. Take resistance readings between body ground and one of the following connectors:
- car phone module (PHM) connector terminal A17 (#17)
- central electronic module (CEM) connector terminal 5D (#B5)
- SRS control module connector terminal 30 (#2B).
The resistance between a fault free cable and body ground should be infinite.

Checking for contact resistance and open-circuits

Check the connectors for the control modules. Check for contact resistance.

Check the collision sensor cable. Check for an open-circuit. Measure the resistance between all the connectors:
- carphone module (PHM) connector terminal A17 (#17)
- central electronic module (CEM) connector terminal 5D (#B5)
- SRS control module connector terminal 30 (#2B).
The resistance of a fault free cable is approximately 0 Ω.

Checking for short-circuits to supply voltage

Check the collision sensor cable. Check for a short-circuit to voltage. Use a voltmeter to take readings between the battery positive terminal and one of the following connectors:
- car phone module (PHM) connector terminal A17 (#17)
- central electronic module (CEM) connector terminal 5D (#B5)
- SRS control module connector terminal 30 (#2B).
Remedy as necessary.

Other information
- To connect the breakout box to the car phone module (PHM), see Connecting the breakout box. Car phone module
- To connect the breakout box to the central electronic module (CEM), see Connecting the breakout box
- To connect the breakout box to the SRS module, see Connecting the breakout box .