DTC B1489: Passenger Air Bag OFF Indicator Light Drive Circuit System Fault 1 (Light does not Switch Off).: Diagnosis

Required Special Tools: 

• MB991958: Scan Tool (MUT-III Sub Assembly)
  • MB991824: V.C.I.
  • MB991827: MUT-III USB Cable
  • MB991910: MUT-III Main Harness A

1. STEP 1. 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 (MUT-III)  ."
   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 2.

   NO :  Repair the CAN bus line (Refer to DIAGNOSIS ).

   Fig 1: Connecting Scan Tool To Data Link Connector

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
2. STEP 2. 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 the DTC set? 

   YES :  Go to Step 3.

   NO :  There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to How to Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTIONS ).

   Fig 2: Connecting Scan Tool To Data Link Connector

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
3. STEP 3. Using scan tool MB991958, read the diagnostic trouble code. 
   1. Turn the ignition switch to the "ON" position.
   2. Check if the DTC is set.
   3. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is DTC B1540, B1541, B1542, B1543, B1545 or B1546 set? 

   YES :  Carry out the troubleshooting of the occupant classification-ECU or the occupant classification sensor system (Refer to < B1540, B1541, B1542, B1543 > , < B1545, B1546 > ).

   NO :  Go to Step 4.

   Fig 3: Connecting Scan Tool To Data Link Connector

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
4. STEP 4 Using scan tool MB991958, check actuator test. 
   • Item No. 3: Passenger air bag OFF indicator light illumination

   Q: Does the passenger air bag indicator light illuminate or go out normally? 

   YES :  Go to Step 5.

   NO :  Replace the passenger air bag OFF indicator light (Refer to INSTRUMENT PANEL ASSEMBLY ). Then go to  Step 6.

5. STEP 5. Check the harness between SRS-ECU connector C-123 (terminal No. 21) and passenger air bag OFF indicator light C-05 (terminal No. 3). 
   • Check the passenger air bag OFF indicator light output lines for open circuit.

   Q: Is the check result satisfactory? 

   YES :  Erase the diagnostic trouble code memory, and check the diagnostic trouble code. If DTC B1489 sets, replace the SRS-ECU (Refer to SRS CONTROL UNIT (SRS-ECU)  ). Then go to Step 6.

   NO :  Repair the harness wires. Then go to Step 6.

   Fig 4: Identifying Connector C-05 Terminals

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   Fig 5: Disconnecting Connector C-123 Terminals

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
6. STEP 6. 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 B1489 set? 

   YES :  Return to  Step 1.

   NO :  The procedure is complete.

   Fig 6: Connecting Scan Tool To Data Link Connector

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.