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Home >> Mitsubishi >> 2006 >> Lancer Evolution L4-2.0L DOHC Turbo >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> Manufacturer Code Charts >> Air Bag Systems >> DTC 28

DTC 28

DTC 28: Passenger's (Front) Seat Belt Pre-Tensioner (Squib) System Fault 1 (Short Circuit between Terminals of the Squib Circuit)

Passenger's (Front) Seat Belt Pre-tensioner (Squib) Part 1:




Passenger's (Front) Seat Belt Pre-tensioner (Squib) Part 2:






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 outputs an ignition signal. At this time, if the front air bag safing G-sensor is on, the pre-tensioner will deploy.

DTC SET CONDITIONS
This DTC is set if there is abnormal resistance between the input terminals of the passenger's seat belt pre-tensioner (squib).

TROUBLESHOOTING HINTS
- Improper engaged connector or defective short spring*
- Short circuit between the passenger's seat belt pre-tensioner (squib) circuit terminals
- Damaged connector(s)
- Malfunction of the SRS-ECU

NOTE: *: The squib circuit connectors integrate a "short" spring (which prevents the seat belt pre-tensioner 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-13 or D-03 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: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991911: M.U.T.-III Main Harness B
- MB991865: Dummy resister
- MB991866: Resister harness (For Pre-tensioner)

STEP 1. 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.




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

Q: Is DTC 34 set?

YES: Go to Step 2.

NO: Go to Step 3.




STEP 2. Check the SRS-ECU connector C-13.

Q: Is connector correctly engaged?

YES: Go to Step 3.

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










STEP 3. Check SRS-ECU connector C-13 and passenger's seat belt pre-tensioner connector D-03 (Using scan tool MB991958, read the diagnostic trouble code).

1. Disconnect the negative battery terminal.
2. Disconnect connectors C-13 and D-03, and then reconnect them. For connector D-03, use a flat-tipped screwdriver to unlock the locking button at the harness side connector by withdrawing it toward you in two stages, and then disconnect the connector.
3. Connector the negative battery terminal.
4. Erase the diagnostic trouble code memory, and check the diagnostic trouble code.

Q: Is DTC 28 set?

YES: Go to Step 4.

NO: The procedure is complete. It is assumed that DTC 28 set as connector C-13 or D-03 was engaged improperly.

STEP 4. Check the passenger's seat belt pre-tensioner (Using scan tool MB991958, read the diagnostic trouble code).




1. Disconnect the negative battery terminal.
2. Disconnect passenger's (front) seat belt pre-tensioner connector D-03. Use a flat-tipped screwdriver to unlock the locking button at the harness connector by withdrawing it toward you in two stages, and then disconnect the connector.







3. Connect special tool MB991865 to special tool MB991884.
4. Connect special tool MB991884 to the D-03 harness connector.
5. Connect the negative battery terminal.
6. Erase the diagnostic trouble code memory, and check the diagnostic trouble code.

Q: Is DTC 28 set?

YES: Go to Step 5.

NO: Replace the passenger's seat belt pre-tensioner. Then go to Step 7.

STEP 5. Check the passenger's seat belt pre-tensioner circuit at the SRS-ECU connector C-13.




1. Disconnect SRS-ECU connector C-13.

DANGER: To prevent the seat belt pre-tensioner from deploying unintentionally, disconnect the passenger's seat belt pre-tensioner connector D-03 to short the squib circuit.







2. Disconnect driver's seat belt pre-tensioner connector D-03. Use a flat-tipped screwdriver to unlock the locking button at the harness connector by withdrawing it toward you in two stages, and then 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.




3. Insert a cable tie [3 mm (0.12 inch) wide, 0.5 mm (0.02 inch) thick] between terminals 27, 28 and the short spring to release the short spring.

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 C-13 harness connector terminals 27 and 28. It should be open circuit.

Q: Does continuity exist?

YES: Go to Step 6.

NO: Erase the diagnostic trouble code memory, and check the diagnostic trouble code. If DTC 28 set, replace the SRS-ECU. Then go to Step 7 .







STEP 6. Check the harness for short circuit between SRS-ECU connector C-13 (terminal No. 27 and 28) and passenger's (front) seat belt pre-tensioner connector D-03 (terminal No.1 and 2).






NOTE:
- After inspecting intermediate connector C-112, inspect the wiring harness.
- If the intermediate connector C-112 is damaged, repair or replace it. Refer to Harness Connector Inspection.

Q: Are harness wires between SRS-ECU connector C-13 (terminal No. 27 and 28) connector and passenger's (front) seat belt pre-tensioner connector D-03 (terminal No.1 and 2) in good condition?

YES: Go to Step 7.

NO: Repair the harness wires between SRS-ECU connector C-13 and passenger's seat belt pre-tensioner connector D-03. Then go to Step 7.

STEP 7. Recheck for diagnostic trouble code DTC.
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 28 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 How to Use Troubleshooting/INSPECTION Service Points - How to Cope with Intermittent Malfunction).
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