Diagnostic Trouble Code (DTC) Information PHM-A238

Condition 

Fig 1: Identifying Phone Module (PHM)

Courtesy of VOLVO CARS CORPORATION

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 (+- 10%). In the event of a collision, the signal frequency increases to 250 Hz (+- 10%).

The diagnostic trouble code (DTC) is stored if the control module detects that:

• The collision signal does not have expected frequency.

The control module's test for the diagnostic trouble code (DTC) starts in the event of:

• Ignition switch position II.
• Battery voltage between 9 - 16 V.

Substitute Value 

• None.

Possible Source 

• The Supplemental restraint system module (SRS) transmits on an unexpected frequency.

Fault symptom[s] 

• Text window and warning symbol/Text message
• Volvo On Call/Other Volvo On Call problems
• Cellular phone/Other cellular phone problems