DTC B1410: Passenger's (Front) Air Bag Module (1st Squib) System Fault 1 (Short Circuit between Terminals of the Squib Circuit); DTC B1490: Passenger's (Front) Air Bag Module (2nd Squib) System Fault 1 (Short Circuit between Terminals of the Squib Circuit): Diagnosis
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A
- MB991865: Dummy resister
- MB991866: Resister harness
- 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.
- Connect scan tool MB991958. Refer to "HOW TO CONNECT THE SCAN TOOL ."
- Turn the ignition switch to the "ON" position.
- Diagnose the CAN bus line.
- 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 ).
- STEP 2. Recheck for diagnostic trouble code.
Check again if the DTC is set.
- Erase the DTC.
- Turn the ignition switch to the "ON" position.
- Check if the DTC is set.
- 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 COPE WITH INTERMITTENT MALFUNCTIONS ).
- STEP 3. Using scan tool MB991958, read the diagnostic trouble code. 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.
- Turn the ignition switch to the "ON" position.
- Check if the DTC is set.
- Turn the ignition switch to the "LOOK (OFF)" position.
Q: Is DTC B1519 set?
YES: Go to Step 4.
NO: Go to Step 5.
- STEP 4. Check SRS-ECU connector C-121.
Q: Is the connector correctly engaged?
YES: Go to Step 5.
NO: Engage the connector correctly. Then go to Step 9.
- STEP 5. Check SRS-ECU connector C-121 and passenger's (front) air bag module connector C-110. (Using scan tool MB991958, read the diagnostic trouble code.)
- Disconnect the negative battery terminal.
- Disconnect connectors C-121 and C-110, and then reconnect them.
- Slide the outer housing of passenger's (front) air bag connector C-110 in the arrow direction shown, and disconnect the connector.
- Connect the negative battery terminal.
- Erase the diagnostic trouble code memory, and check the diagnostic trouble code.
Q: Is DTC B1410 < 1st squib > or B1490 < 2nd squib > set?
YES: Go to Step 6.
NO: The procedure is complete. It is assumed that DTC B1410 < 1st squib > or B1490 < 2nd squib > set as connector C-121 or C-110 was engaged improperly.
- STEP 6. Check the passenger's (front) air bag. (Using scan tool MB991958, read the diagnostic trouble code.)
- Disconnect the negative battery terminal.
- Disconnect the passenger's (front) air bag connector C-110.
- Slide the outer housing of passenger's (front) air bag connector C-110 in the arrow direction shown, and disconnect the connector.
- 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.
- Insert special tool MB991866 into the harness side connector C-110 (terminal No.1 and 2 < 1st squib > or terminal No.3 and 4 < 2nd squib >) by backprobing.
- Connect the negative battery terminal.
- Erase the diagnostic trouble code memory, and check the diagnostic trouble code.
Q: Is DTC B1410 < 1st squib > or B1490 < 2nd squib > set?
YES: Go to Step 7.
NO: Replace the passenger's (front) air bag (Refer to AIR BAG MODULES AND CLOCK SPRING ). Then go to Step 9.
- STEP 7. Check the passenger's (front) air bag circuit at SRS-ECU connector C-121.
- Disconnect SRS-ECU connector C-121.
WARNING: To prevent the air bag from deploying unintentionally, disconnect the passenger's (front) air bag module connector C-110 to short the squib circuit.
- Disconnect the passenger's (front) air bag connector C-110.
- Slide the outer housing of passenger's (front) air bag connector C-110 in the arrow direction shown, and disconnect the connector.
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.
- Insert a cable tie [3 mm (0.12 inch) wide, 0.5 mm (0.02 inch) thick] between terminals 27 and 28 < 1st squib > or 30 and 31 < 2nd squib >, and the short spring to release the short spring.
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
CAUTION: Do not insert a test probe into the terminal from its front side directly as the connector contact pressure may be weakened. - Check for continuity between C-121 harness side connector terminals 27 and 28 < 1st squib > or 30 and 31 < 2nd squib >.
It should be open circuit.
Q: Does continuity exist?
YES: Erase the diagnostic trouble code memory, and check the diagnostic trouble code. If DTC B1410 < 1st squib > or B1490 < 2nd squib > set, replace the SRS-ECU (Refer to SRS CONTROL UNIT (SRS-ECU) ). Then go to Step 9.
NO: Go to Step 8.
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
- Disconnect SRS-ECU connector C-121.
- STEP 8. Check the harness for short circuit between SRS-ECU connector C-121 (terminal No.27 and 28 < 1st squib > or terminal No.30 and 31 < 2nd squib >) and passenger's (front) air bag connector C-110 (terminal No.1 and 2 < 1st squib > terminal No.3 and 4 < 2nd squib >).
NOTE: After inspecting intermediate connector C-22 inspect the wiring harness. If the intermediate connector C-22 is damaged, repair or replace it.
Q: Are harness wires between SRS-ECU connector C-121 (terminal No.27 and 28 < 1st squib > or terminal No.30 and 31 < 2nd squib >) and passenger's (front) air bag module connector C-110 (terminal No.1 and 2 < 1st squib > terminal No.3 and 4 < 2nd squib >) in good condition?
YES: Go to Step 9.
NO: Replace the harness wires between SRS-ECU connector C-121 and passenger's (front) air bag module connector C-110. Then go to Step 9.
- STEP 9. Check for diagnostic trouble code.
Check again if the DTC is set.
- Erase the DTC.
- Turn the ignition switch to the "ON" position.
- Check if the DTC is set.
- Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC B1410 < 1st squib > or B1490 < 2nd squib > set?
YES: Return to Step 1.
NO: The procedure is complete.