DTC P3107-11: Lost Communication With Airbag System Control Module Circuit Short To Ground: Notes

1. - 

Outline of diagnosis: 

Short circuit to ground in communication lines

Communication signal pulse from AIRBAG CONTROL MODULE was lost, and Low continued for a predetermined period of time

(1 trip detection logic)

Trouble symptom: 

Normal driving

Wiring diagram: 

Hybrid system Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>HYBRID ELECTRIC VEHICLE SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DTC  .

   Read the DTC of [Airbag] using the Subaru Select Monitor. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Are any DTCs displayed?

   Yes  : Perform the diagnosis for the displayed DTCs. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   No  : Go to  2.

2. CHECK AIRBAG CONTROL MODULE (WAVEFORM MEASUREMENT)  .
   CAUTION: To measure the voltage and resistance of airbag system component, be sure to use the specified test harness. Ref. to AIRBAG (DIAGNOSTICS)>GENERAL DESCRIPTION>PREPARATION TOOL .
   1. Turn the ignition to OFF.
   2. Connect an oscilloscope to each terminal of AIRBAG CONTROL MODULE.
   3. Turn to READY ON.
   4. Using an oscilloscope, measure the waveform between the connector terminals of each terminal in AIRBAG CONTROL MODULE. (With the connector connected)

      Connector & terminal 

      (AB6) No. 14 - (AB6) No. 25:

      Gauge set: 5 V/DIV, 500 ms/DIV

      Measurement condition: READY ON

      Courtesy of SUBARU OF AMERICA, INC.

   Can the reference waveform above be measured?

   Yes  : Go to  3.

   No  : Go to  4.

3. CHECK DTC  .
   1. Turn to IG ON.
   2. Using the Subaru Select Monitor, perform the clear memory of [P-HEV Hybrid Powertrain Control]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
   3. Read the DTC of [P-HEV Hybrid Powertrain Control] using the Subaru Select Monitor. Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC P310711 displayed?

   Yes  : Replace Hybrid vehicle control ECU assembly. Ref. to HYBRID ELECTRIC VEHICLE>HYBRID POWERTRAIN CONTROL MODULE .

   No  : Even if DTC is displayed, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

   NOTE: In this case, temporary poor contact of connector, or temporary open or short circuit of the Wire harness may be the cause.
4. CHECK AIRBAG CONTROL MODULE  .
   CAUTION: To measure the voltage and resistance of airbag system component, be sure to use the specified test Wire harness. Ref. to AIRBAG (DIAGNOSTICS)>GENERAL DESCRIPTION>PREPARATION TOOL .
   1. Turn the ignition to OFF.
   2. Disconnect AIRBAG CONTROL MODULE connector (AB6).
   3. Using a tester, measure the resistance between AIRBAG CONTROL MODULE connector terminals.

      Connector & terminal 

      (AB6) No. 14 - (AB6) No. 25:

   Is the resistance 10 kΩ or more?

   Yes  : Go to  5.

   No  : Replace AIRBAG CONTROL MODULE. Ref. to AIRBAG SYSTEM>AIRBAG CONTROL MODULE .

5. CHECK Wire harness AND CONNECTOR (Hybrid vehicle control ECU assembly - AIRBAG CONTROL MODULE) (SHORT TO GROUND)  .
   1. Disconnect Hybrid vehicle control ECU assembly connector (i369).
   2. Using a tester, measure the resistance between terminals in Hybrid vehicle control ECU assembly connector, and between Hybrid vehicle control ECU assembly connector and chassis ground.

      Connector & terminal 

      (i369) No. 7 - (i369) No. 1 - 35:

      (i369) No. 7 - Chassis ground:

   Is the resistance 10 kΩ or more?

   Yes  : Replace Hybrid vehicle control ECU assembly. Ref. to HYBRID ELECTRIC VEHICLE>HYBRID POWERTRAIN CONTROL MODULE .

   No  : Repair or replace the Wire harness between Hybrid vehicle control ECU assembly and AIRBAG CONTROL MODULE connector.