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Home >> Volvo >> 2007 >> C70 Automatic >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Entertainment Systems >> Phone Module, Subwoofer Module, GPS Module, And Traffic Message Channel Module - Diagnostic Trouble Codes >> PHM-A238: Crash Signal Faulty Signal (2009-2013) >> Faulty Signal >> Checking The Component And Wiring
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Checking The Component And Wiring

Phone module (PHM) receives a directly connected signal from Supplemental restraint system module (SRS) that informs if the vehicle has been involved in a collision. The signal is pulse width modulated and normally has a frequency of 10 Hz. In the event of a collision, the signal frequency increases to 250 Hz (+- 10%).

Check that the status of the Supplemental restraint system module (SRS) is approved. Any diagnostic trouble codes stored in the Supplemental restraint system module (SRS) are to be rectified first.

Connect the adapter cable and breakout box to Phone module (PHM) connector A.

Check that the pulse width modulated signal is between 9 and 11 Hz by reading the frequency between terminals #C1:17 and #C1:6.

If the cable is damaged, replace it.

Other information 

Fig 1: Identifying Phone Module (PHM)
GLL163991Courtesy of VOLVO CARS CORPORATION

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