DTC 25

Passenger's (Front) Air Bag Module (Squib) System Fault 2 (Open in the Squib Circuit)

Passenger's (Front) 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.


DTC SET CONDITIONS
This DTC is set if an open circuit is detected between the terminals of the passenger's 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
- Open circuit in the passenger's air bag module (squib) circuit
- Improper connector contact Malfunction of the SRS-ECU

DIAGNOSIS

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

STEP 1. Check the passenger's air bag module.




1. Disconnect the passenger's air bag module connector C-12.




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 C-12 harness side connector by backprobing.
4. Connect the negative battery terminal.
5. Erase the DTC memory, and then recheck the DTC.

Q: Is DTC 25 output?

YES: Go to Step 2.
NO: Replace the passenger's air bag module. Then go to Step 3.

STEP 2. Check the harness Wires f6r open circuit between the SRS-ECU connector C-137 (terminal No.5 and 6) and the passenger's air bag module connector C-12 (terminal No.1 and 2).







1. Disconnect the SRS-ECU connector C-137 and the passenger's air bag module connector C-12.

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




2. Check for continuity between the following terminals.
C-137 connector C-12 connector
6 - 1

5 - 2

It should be less than 2 ohms.

Q: Does continuity exist?

YES: Erase the DTC memory, and recheck if any DTC sets. If DTC 25 sets, replace the SRS-ECU. Then go to Step 3.
NO: Repair the harness wires between the SRS-ECU connector C-137 and the passenger's air bag module connector C-12. Then go to Step 3.

STEP 3. Check the DTC.

Q: Is DTC 25 output?

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.)