DTC 71: Side-Airbag Module (RH) (Squib) System Fault 1 (Short Circuit between Terminals of the Squib Circuit): Diagnosis

Required Special Tools: 

• MB991502: Scan Tool (MUT-II)
• MB991865: Dummy Resistor
• MB991866: Resistor Harness
• MB991223 (MB991222): Harness Set (Probe)

1. STEP 1. Check the DTC. 

   Q: Is DTC 34 set? 

   YES  : Go to Step 2.

   NO:  Go to  Step 3.

2. STEP 2. Check the SRS-ECU connector C-145. 

   Q: Is the connector correctly engaged? 

   YES  : Go to Step 3.

   NO:  Engage the connector correctly. Then go to  Step 7.

   Fig 1: Identifying Connector C-145

   Courtesy of DAIMLERCHRYSLER CORPORATION
3. STEP 3. Check the SRS-ECU connector C-145 and the side-airbag module (RH) connector D-24. 
   1. Disconnect the negative battery terminal.
   2. Disconnect the connectors C-145 and D-24, and then reconnect them.
   3. Connect the negative battery terminal.
   4. Erase the DTC memory, and then recheck the DTC.

   Q: Is DTC 71 set? 

   YES  : Go to Step 4.

   NO:  The procedure is complete. It is assumed that DTC 71 set as the connector C-145 or D-24 was engaged improperly.

   Fig 2: Identifying Connector C-145

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   Fig 3: Identifying Connector D-24

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4. STEP 4. Check the side-airbag module (RH). 
   1. Disconnect the negative battery terminal.
   2. Disconnect the side-airbag module (RH) connector D-24.
      Fig 4: Identifying Connector D-24

      Courtesy of DAIMLERCHRYSLER CORPORATION
   3. Connect special tool MB991865 to special tool MB991866.
      CAUTION: Do not insert a test probe into the terminal from its front side directly as the connector contact pressure may be weakened.
   4. Insert special tool MB991866 into the D-24 harness side connector by backprobing.
   5. Connect the negative battery terminal.
   6. Erase the DTC memory, and then recheck the DTC.
      Fig 5: Identifying Dummy Resistor

      Courtesy of DAIMLERCHRYSLER CORPORATION

   Q: Is DTC 71 set? 

   YES  : Go to Step 5.

   NO:  Replace the seatback assembly of the front seat (RH) (Refer to FRONT SEAT ASSEMBLY ). Then go to  Step 7.

5. STEP 5. Check the side-airbag module (RH) circuit at the SRS-ECU connector C-145. 
   1. Disconnect the SRS-ECU connector C-145.
      Fig 6: Identifying Connector C-145

      Courtesy of DAIMLERCHRYSLER CORPORATION
      WARNING: To prevent the side-airbag from deploying unintentionally, disconnect the side-airbag module (RH) connector D-24 to short the squib circuit.
   2. Disconnect the side-airbag module (RH) connector D-24.
      Fig 7: Identifying Connector D-24

      Courtesy of DAIMLERCHRYSLER CORPORATION
      CAUTION: Insert an insulator such as a cable tie to a depth of 4mm (0.16 inch) or more, otherwise the short spring will not be released.
   3. Insert a cable tie [3 mm (0.12 inch) wide, 0.5 mm (0.02 inch) thick] between the terminals 23, 24 and the short spring to release the short spring.
      Fig 8: Inserting Cable Tie Into Short Spring

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      CAUTION: Do not insert a test probe into the terminal from its front side directly as the connector contact pressure may be weakened.
   4. Check for continuity between the C-145 harness side connector terminals 23 and 24.

      It should be open circuit.

   Q: Does continuity exist? 

   YES  : Go to Step 6.

   NO:  Erase the DTC memory, and recheck if any DTC sets. If DTC 71 sets, replace the SRS-ECU (Refer to SRS CONTROL UNIT (SRS-ECU)  ). Then go to  Step 7.

   Fig 9: Checking Continuity Between C-145 Harness Side Connector Terminals 23 And 24

   Courtesy of DAIMLERCHRYSLER CORPORATION
6. STEP 6. Check the harness wires for short circuit between the SRS-ECU connector C-145 (terminal No.23 and 24) and the side-airbag module (RH) connector D-24 (terminal No.1 and 2). 

   Q: Are the harness wires between the SRS-ECU connector C-145 (terminal No.23 and 24) and the side-airbag module (RH) connector D-24 (terminal No.1 and 2) in good condition? 

   YES  : Go to Step 7.

   NO:  Repair the harness wires between the SRS-ECU connector C-145 and the side-airbag module (RH) connector D-24. Then go to Step 7.

   Fig 10: Identifying Connector C-145

   Courtesy of DAIMLERCHRYSLER CORPORATION
   Fig 11: Identifying Connector D-24

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7. STEP 7. Check for DTC. 

   Q: Is DTC 71 set? 

   YES  : Return to  Step 1.

   NO:  The procedure is complete (If no malfunctions are found in all steps, an intermittent malfunction is suspected. Refer to TO COPE WITH INTERMITTENT MALFUNCTION ).