DTC 25

Passenger's (Front) Air Bag Module (Squib) System Fault 2

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

CIRCUIT OPERATION
- The SRS-ECU judges how severe a collision is by detecting signals from the left and right side impact sensors and the analog G-sensor. If the impact is over a predetermined level, the SRS-ECU outputs an ignition signal. At this time, if the 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
These DTC are output if there is abnormal resistance between the in put terminals of the passenger's (front) air bag module (squib). The most likely causes for this code to be set are shown in the table. However, if no DTC resets, the SRS warning light will be switched off (The DTC will be retained).

TROUBLESHOOTING HINTS
- Improper engaged connector or defective short bar*
- 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" 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 is damaged or improperly engaged, the short bar may not be released when the connector is connected. Disconnect connectors C-11 and C-72 and reconnect them before proceeding the diagnosis below. After erasing the diagnostic trouble code in the ECU memory, check if the diagnostic trouble code set again. If the diagnostic trouble code does not set, it is suspected that the diagnostic trouble code above set due to the improper engaged connector.

DIAGNOSIS

Required Special Tools:
- MB991502: Scan Tool (MUT-II)
- MB991865: Dummy resister
- MB991866: Resister harness




STEP 1. Check the passenger's (front) air bag module line using the scan tool, MB991865 dummy resistor and MB991866 resistor harness.
1. Connect the dummy resistor (MB991865) to the resistor harness (MB991866).

CAUTION: Do not directly insert a probe or other devices at the front of the connector to avoid a possible decrease in the contact pressure.

2. Disconnect the passenger's (front) air bag module connector C-11 and insert the resistor harness (MB991866) behind the harness side connector.
3. Connect the negative (-) terminal of the battery.
4. Check the diagnostic trouble code again after erasing the memory.

Q: Is the DTC output?

YES: Go to Step 2.

NO: Replace the (front) air bag module. Then go to Step 3.







STEP 2. Check the harness wires between SRS-ECU connector C-72 and passenger's (front) air bag module connector C-11.

Q: Are the harness wires between SRS-ECU connector C- 72 and passenger's (front) air bag module connector C-11 in good condition?

YES: Go to Step 3.

NO: Repair them. Then go to Step 3.

STEP 3. Check for DTC.

Q: Is any of DTC 24, 25, 64 or 65 output?

YES: Replace the SRS-ECU.

NO: This diagnosis is complete. (If no malfunctions are not found in all steps, an intermittent malfunction is suspected. Refer to How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction.)