FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
Courtesy of Operation CHARM: Car repair manuals for everyone.
Home >> Chrysler >> 2003 >> Sebring Coupe V6-3.0L VIN H >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> Manufacturer Code Charts >> Restraint System >> DTC 21

DTC 21

Driver's Air Bag Module (Squib) System Fault 1 (Short Circuit between Terminals of the Squib Circuit)

Driver's Air Bag Module (Squib) Circuit:






CIRCUIT OPERATION
- The SRS-ECU judges how severe a collision is by detecting signals from 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 SRS air bag will inflate.
- The ignition signal is input to the air bag module via the clock spring to inflate the air bag.

DTC SET CONDITIONS
- This DTC is set if a short circuit is detected between the terminals of the driver's side air bag module (squib). However, if the vehicle condition returns to normal, the SRS warning light will go out, but the DTC will be retained.

TROUBLESHOOTING HINTS
- Improper engaged connector or defective short bar*
- Short circuit in the clock spring
- Short circuit between the driver's air bag module (squib) circuit terminals
- Damaged connector(s)
- Malfunction of the SRS-ECU

NOTE: *: The squib circuit connectors integrate a "short" bar (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 the connector C-137, C-204 or C-208 is damaged or improperly engaged, the short bar may not be released when the connector is connected.

DIAGNOSIS

Required Special Tools:
- MB991502:Scan Tool(MUT-II)
- MB991613: SRS Check Harness
- MB991865: Dummy Resistor
- MB991866: Resistor Harness
- MB991223 (MB991222): Harness Set (Probe)

STEP 1. Check the DTC.

Q: Is DTC 34 set?

YES: Go to Step 2.
NO: Go to Step 3.




STEP 2. Check the SRS-ECU connector C-137.

Q: Is the connector correctly engaged?

YES: Go to Step 3.
NO: Engage the connector correctly. Then go to Step 8.

STEP 3. Check the SRS-ECU connector C-137, the clock spring connector C-204 and the driver's air bag module connector C-208.







1. Disconnect the connectors C-137, C-204 and C-208, and then reconnect them:

NOTE: For the driver's air bag module connector C-208, there should be no gap at the place B shown in the illustration.




2. Connect the negative battery terminal.
3. Erase the DTC memory, and then check the DTC.

Q: Is DTC 21 set?

YES: Go to Step 4.
NO: The procedure is complete. It is assumed that DTC 21 set as the connector C-137, C-204 or C-208 was engaged improperly.

STEP 4. Check the SRS-ECU to clock spring line.




1. Release the clock spring connector C-204 (4-pin).




2. 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.




3. Insert special tool MB991866 into the clock spring harness side connector C-204 (terminal No.3 and 4) by backprobing.
4. Connect the negative battery terminal.
5. Erase the DTC memory, and then recheck the DTC.

Q: Is DTC 21 set?

YES: Go to Step 6.
NO: Go to Step 5.

STEP 5. Check the clock spring and the driver's air bag module.
1. Disconnect the negative battery terminal.




2. Connect connector (4) of special tool MB991613 to clock spring connector C-208.
3. Connect connector (1) of special tool MB991613 to connector (2).
4. Connect terminals 22 to 24, and terminals 23 to 25 of special tool MB991613 to connector (5).
5. Connect the clock spring to the instrument panel wiring harness.
6. Connect the negative battery terminal.
7. Erase the DTC memory, and then recheck the DTC.

Q: Is DTC 21 set?

YES: Replace the clock spring. Then go to Step 8.
NO: Replace the driver's air bag module. Then go to Step 8.

STEP 6. Check the driver's air bag module circuit at the SRS-ECU connector C-137.




1. Disconnect the SRS-ECU connector C-137.

DANGER: To prevent the air bag from deploying unintentionally, disconnect the clock spring connector C-204 to short the squib circuit.

2. Disconnect the clock spring connector C-204.





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




3. Insert a cable tie [3 mm (0.12 inch) wide, 0.5 mm (0.02 inch) thick] between the terminals 7, 8 and the short bar to release the short bar.

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 the C-137 harness side connector terminals 7 and 8.
It should be open circuit.

Q: Does continuity exist?

YES: Erase the DTC memory, and recheck if any DTC sets. If DTC 21 sets, replace the SRS-ECU. Then go to Step 8.
NO: Go to Step 7.







STEP 7. Check the harness wires for short circuit between the SRS-ECU connector C-137 (terminal No.7 and 8) and the clock spring connector C-204 (terminal No.3 and 4).

Q: Are the harness wires between the SRS-ECU connector C-137 (terminal No.7 and 8) and the clock spring connector C-204 (terminal No.3 and 4) in good condition?

YES: Go to Step 8.
NO: Repair the harness wires between the SRS-ECU connector C-137 and the clock spring connector C-204. Then go to Step 8.

STEP 8. Check the DTC.

Q: Is DTC 21 set?

YES: Return to Step 1.
NO: The procedure is complete. (If no malfunctions are not found in all steps, an intermittent malfunction is suspected. Refer to INTRODUCTION, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction.)
pro multis Credits:Operation CHARM About Operation CHARM