DTC B212C: Open Circuit to IG1 Power Supply (Fuse No. 12 Circuit); DTC B212D: Open Circuit to IG1 Power Supply (Fuse No. 18 Circuit): Diagnosis

Required Special Tools: 

• MB991958: Scan Tool (M.U.T.-III Sub Assembly)
  • MB991824: Vehicle Communication Interface (V.C.I.)
  • MB991827: M.U.T.-III USB Cable
  • MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)

1. STEP 1. Power supply fuse number 12, 18 check. 

   Q: Is the fuse in good condition? 

   • YES:  Go to  Step 3.
   • NO:  Go to Step 2
2. STEP 2. Check for a blown fuse. 
   1. Replace the fuse.
   2. Turn the ignition switch to the "ON" position, wait for at least one minute and then turn the switch off.
   3. Check the fuse.

   Q: Is the fuse in good condition? 

   • YES:  Go to Step 3.
   • NO:  Repair the wiring harness between the C-313 ETACS-ECU connector terminal No. 4/2 and the C-30 SRS-ECU connector terminal No. 61/62, and replace the power supply fuse.
3. STEP 3. Using scan tool MB991958, diagnose the CAN bus line. 
   CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
   1. Connect scan tool MB991958. Refer to "HOW TO CONNECT THE SCAN TOOL  ."
   2. Turn the ignition switch to the "ON" position.
   3. Diagnose the CAN bus line.
   4. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is the CAN bus line found to be normal? 

   • YES:  Go to Step 4.
   • NO:  Repair the CAN bus line (Refer to DIAGNOSIS ).
     Fig 1: Connecting Special Tool MB991910 To Data Link Connector

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
4. STEP 4. Using scan tool MB991958, diagnose the ETACS. 
   CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
   1. Connect scan tool MB991958. Refer to "HOW TO CONNECT THE SCAN TOOL  ."
   2. Turn the ignition switch to the "ON" position.
   3. Check if the DTC is set.
   4. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is the DTC set? 

   • YES:  Diagnose the ETACS (Refer to DIAGNOSIS ). Then go to  Step 9.
   • NO:  Check the input signal of ETACS-ECU ignition switch (IG1) (Refer to INSPECTION PROCEDURE 2: MALFUNCTION OF THE IGNITION SWITCH (IG1) INPUT/OUTPUT SIGNAL ). Then go to step 5.
5. STEP 5. Recheck for diagnostic trouble code. 

   Check again if the DTC is set.

   1. Erase the DTC.
   2. Turn the ignition switch to "ON" position.
   3. Check if the DTC is set.
   4. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is the DTC set? 

   • YES:  Go to Step 6.
   • NO:  There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
6. STEP 6. Resistance measurement at the C-122 SRS-ECU connector. 
   1. While pushing the part "A" indicated in the illustration of the harness side connector, turn the lock lever to the direction of the arrow to release the lock lever, and disconnect the C-122 SRS-ECU connectors.
      Fig 2: Turning Lock Lever

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   2. Take the measurements below at the C-122 wiring harness side connectors. It should be less than 2 ohms.
      • Continuity between C-122 wiring harness side connector terminal No. 17 and body ground

   Q: Does continuity exist? 

   • YES:  Go to Step 7.
   • NO:  Repair the wiring harness between the C-122 SRS-ECU connector terminal No. 17 and the ground.
     Fig 3: Checking Continuity Between C-122 Wiring Harness Side Connector Terminal 17 And Body Ground

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
7. STEP 7. Measure the voltage at the C-30 SRS-ECU connector. 
   1. Disconnect the negative battery terminal.
   2. While pushing the part "A" indicated in the illustration of the harness side connector, turn the lock lever to the direction of the arrow to release the lock lever, and disconnect the C-30 SRS-ECU connector.
   3. Connect the negative battery terminal.
   4. Ignition switch: ON
      Fig 4: Turning Lock Lever

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   5. Take the measurements below at the C-30 harness side connector.
      • Voltage between terminal No. 61/62 and body ground

        OK: 9 V or more 

   Q: Is the measured voltage within the specified range? 

   • YES:  Go to  Step 9.
   • NO:  Go to Step 8.
     Fig 5: Checking Voltage Between Terminal 61, 62 And Body Ground

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
8. STEP 8. Check the harness for open circuit between SRS-ECU connector C-30 (terminal No. 61 and 62) and the ETACS-ECU connector C-313 (terminal No. 4 and 2). 
   1. Disconnect the negative battery terminal.
   2. While pushing the part "A" indicated in the illustration of the harness side connector, turn the lock lever to the direction of the arrow to release the lock lever, and disconnect the C-30 SRS-ECU connector.
   3. Disconnect the ETACS-ECU connector C-313.
      Fig 6: Turning Lock Lever

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   4. Check for continuity between the following terminals. It should be less than 2 ohms.

      < Fuse No. 12 >

      • SRS-ECU connector C-30 (terminal No. 62) and the ETACS-ECU connector C-313 (terminal No. 2)

      < Fuse No. 18 >

      • SRS-ECU connector C-30 (terminal No. 61) and the ETACS-ECU connector C-313 (terminal No. 4)

   Q: Does continuity exist? 

   • YES:  Replace the ETACS-ECU (Refer to ETACS-ECU ).
   • NO:  Repair the harness wire between SRS-ECU connector C-30 and the ETACS-ECU connector C-313.
     Fig 7: Checking Continuity Between SRS-ECU Connector C-30 (Terminal 62) And ETACS-ECU Connector C-313 (Terminal 2)

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
9. STEP 9. Recheck for diagnostic trouble code. 

   Check again if the DTC is set.

   1. Erase the DTC.
   2. Turn the ignition switch to the "ON" position.
   3. Check if the DTC is set.
   4. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is DTC B212C < Fuse No. 12 circuit > or B212D < Fuse No. 18 circuit > set? 

   • YES:  Replace the SRS-ECU (Refer to SRS CONTROL UNIT (SRS-ECU)  ).
   • NO:  There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).