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Home >> Mitsubishi >> 2009 >> Lancer L4-2.0L (4B11) >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> B Code Charts >> B1B0F

B1B0F

DTC B1B0B: Passenger's (Front) Air Bag Module (1st squib) System (Short Circuit Between Squib Circuit Terminals)

DTC B1B0F: Passenger's (Front) Air Bag Module (2nd squib) System (Short Circuit Between Squib Circuit Terminals)


Passenger's (Front) Air Bag Module (Squib) Circuit:






CAUTION: If DTC B1B0B [1st squib] or B1B0F [2nd squib] is set in the SRS-ECU, always diagnose the CAN main bus line.

CIRCUIT OPERATION

- The SRS-ECU judges how severe a collision is by detecting signals from the front impact sensors and the front air bag analog G-sensor. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the front air bag safing G-sensor is on, the SRS air bag will inflate.
- The ignition signal is input to the air bag module to inflate the air bag.

DTC SET CONDITIONS

This DTC is set if there is abnormal resistance between the input terminals of the passenger's (front) air bag module (squib).

TROUBLESHOOTING HINTS

- Improper engaged connector or defective short spring*
- Short circuit between the passenger's (front) air bag module (squib) circuit terminals
- Damaged connector(s)
- Malfunction of the SRS-ECU

NOTE: *: The squib circuit connectors integrate a "short" spring (which prevents the air bag from deploying unintentionally due to static electricity by shorting the positive wire to the ground wire in the squib circuit when the connectors are disconnected). Therefore, if connector C-16 or C-122 is damaged or improperly engaged, the short spring may not be released when the connector is connected.

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)

- 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.







1. Connect scan tool MB991958. Refer to "How to connect the scan tool". How To Connect The Scan Tool (M.U.T.-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.

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.

STEP 3. Check SRS-ECU connector C-122 and passenger's (front) air bag module connector C-16.

1. Disconnect the negative battery terminal.







2. While pressing the part A in the illustration of the C-122 SRS-ECU harness side connector, turn the lock lever toward the arrow direction to release the lock lever. Then, disconnect the connector and reconnect it.







3. Disconnect C-16 passenger's (front) air bag module harness side connector while sliding toward the arrow direction, and then reconnect it.
4. Connect the negative battery terminal.
5. Erase the diagnostic trouble code memory, and check the diagnostic trouble code.

Q: Is DTC B1B0B [1st squib] or B1B0F [2nd squib] set?

YES: Go to Step 4.

NO: The procedure is complete. It is assumed that DTC B1B0B [1st squib] or B1B0F [2nd squib] set as connector C-122 or C-16 was engaged improperly.

STEP 4. Check the passenger's (front) air bag module.

1. Disconnect the negative battery terminal.







2. Disconnect C-16 passenger's (front) air bag module harness side connector while sliding toward the arrow direction.







3. Connect special tool MB991865 to special tool MB991866.

CAUTION: Do not insert a probe into the terminal from its front side directly as the connector contact pressure may be weakened.

4. Insert special tool MB991866 into the harness side connector C-16 (terminal No.1 and 2 [1st squib] or terminal No.3 and 4 [2nd squib]) by backprobing.
5. Connect the negative battery terminal.

CAUTION: Always DTC B1B0E is set when checking DTC B1B0B. This is because the second side terminal is isolated when checking it. DTC B1B0E is set but this is not a fault. In addition, always DTC B1B0A is set when checking DTC B1B0F because the first side terminal is isolated.

6. Erase the diagnostic trouble code memory, and check the diagnostic trouble code.

Q: Is the checked DTC set?

YES: Go to Step 5.

NO: Replace the passenger's (front) air bag module. Then go to Step 7.

STEP 5. Check the passenger's (front) air bag module circuit at SRS-ECU connector C-122.

1. Disconnect the negative battery terminal.







2. While pushing the part "A" indicated in the figure 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 connector.

DANGER: To prevent the air bag from deploying unintentionally, disconnect the passenger's (front) air bag module connector C-16 to short the squib circuit.







3. Disconnect C-16 passenger's (front) air bag module harness side connector while sliding toward the arrow direction.







CAUTION: Insert an insulator such as a cable tie to a depth of 4 mm (0.16 inch) or more, otherwise the short spring will not be released.

4. Insert a cable tie [3 mm (0.12 inch) wide, 0.5 mm (0.02 inch) thick] between terminals 7 and 8 [1st squib] or 11 and 12 [2nd squib], and the short spring to release the short spring.







5. Check for continuity between C-122 harness side connector terminals 7 and 8 [1st squib] or 11 and 12 [2nd squib]. It should be open circuit.

Q: Is it open circuit?

YES: Erase the diagnostic trouble code memory, and check the diagnostic trouble code. If DTC B1B0B [1st squib] or B1B0F [2nd squib] set, replace the SRS-ECU. Then go to Step 7.

NO: Go to Step 6.

STEP 6. Check the harness for short circuit between SRS-ECU connector C-122 (terminal No.7 and 8 [1st squib] or terminal No.11 and 12 [2nd squib]) and passenger's (front) air bag module connector C-16 (terminal No.2 and 1 [1st squib] terminal No.4 and 3 [2nd squib]).

Q: Are harness wires between SRS-ECU connector C-122 (terminal No.7 and 8 [1st squib] or terminal No.11 and 12 [2nd squib]) and passenger's (front) air bag module connector C-16 (terminal No.2 and 1 [1st squib] terminal No.4 and 3 [2nd squib]) in good condition?

YES: Go to Step 7.

NO: Replace the harness wires between SRS-ECU connector C-122 and passenger's (front) air bag module connector C-16. Then go to Step 7.

STEP 7. Check 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 B1B0B [1st squib] or B1B0F [2nd squib] set?

YES: Return to Step 1.

NO: The procedure is complete.
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