DTC B1B23: Curtain Air Bag Module (RH) (Squib) System (Short Circuit between Squib Circuit Terminals)

CIRCUIT OPERATION

• The SRS-ECU judges how severe a collision is by detecting signals from the side impact sensors installed on the lower side of the center pillar. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the side collision safing G-sensor is on, the SRS air bag will inflate.
  
• The ignition signal is input to the curtain air bag module (RH) to inflate the curtain air bag.
  

DTC SET CONDITIONS

TROUBLESHOOTING HITS

• Improper engaged connector or defective short spring*
  
• Short circuit between the curtain air bag module (RH) (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) (Refer to ). Therefore, if connector C-30, D-10 or F-05 is damaged or improperly engaged, the short spring may not be released when the connector is connected.

(1) 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. Connect scan tool MB991958. Refer to "How to connect the scan tool ." (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? Go to Step 2. Repair the CAN bus line (Refer to GROUP 54C, Diagnosis ).

	Go to Step 3.

	There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

(2)While pressing the part A in the illustration of the C-30 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 the F-05 connector, and then reconnect it. Use a flat-tipped (-) screwdriver to pull out the F-05 curtain air bag module harness side connector locking button toward the arrow direction, release the lock, and then disconnect the connector.

(4)Disconnect the D-10 connector’s, and then reconnect them. Unlock the connector by sliding the locking button to the direction of the arrow as shown in the figure, and then disconnect the connector. (5)Connect the negative battery terminal. (6)After erasing the diagnostic trouble code memory, check the diagnostic trouble code again. (7)Disconnect the negative battery terminal. Q. Is DTC B1B23 set? Go to Step 4. Intermittent Malfunction (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).

(2)Disconnect the D-10 intermediate connector unlock the connector by sliding the locking button to the direction of the arrow as shown in the figure, and then disconnect the connector.

(3)Connect special tool MB991865 to special tool MB991866. (4) caution Do not insert a probe into the terminal from its front side directly, as the connector contact pressure may be weakened. Insert the probe of resistor harness, to which the dummy resistor is installed, from the back of D-10 intermediate connector (floor harness side). (5)Connect the negative battery terminal. (6)After erasing the diagnostic trouble code memory, check the diagnostic trouble code again. Q. Is DTC B1B23 set? Go to Step 5. Go to Step 6.

(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-30 SRS-ECU connector.

(3) danger To prevent the air bag from deploying unintentionally, disconnect the intermediate connector D-10 to short the squib circuit. Disconnect the D-10 intermediate connector unlock the connector by sliding the locking button to the direction of the arrow as shown in the figure, and then disconnect the connector.

(4) caution The short spring may not be released due to the insufficient insertion. Therefore, insert the insulator for 4 mm (0.6 inch) or more. Insert a cable tie [3 mm (0.12 inch) wide, 0.5 mm (0.02 inch) thick] between terminal 39, 40 and the short spring to release the short spring.

(5)Check for continuity between the C-30 wiring harness side connector terminal No. 39 and No. 40. It should be open circuit. Q. Is it open circuit? Go to Step 7. Repair the wiring harness.

(2) danger To prevent the air bag from deploying unintentionally, disconnect the curtain air bag module connector F-05 to short the squib circuit. Disconnect curtain air bag module (RH) F-05. 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)Disconnect the D-10 intermediate connector unlock the connector by sliding the locking button to the direction of the arrow as shown in the figure, and then disconnect the connector.

(4)Because the short spring is installed to the D-10 intermediate connector (curtain air bag harness side), insert a cable tie [3 mm (0.12 inch) wide, 0.5 mm (0.02 inch) thick] between terminals 1, 2 and the short spring to release the short spring.

(5) caution Do not insert a probe into the terminal from its front side directly, as the connector contact pressure may be weakened. Check for continuity between the D-10 intermediate connector (curtain air bag harness side) terminal No.1 and 2. It should be open circuit. Q. Is it open circuit? Replace the curtain air bag module (RH) (Refer to ). Then go to Step 7. Repair the wiring harness.

	Replace SRS-ECU (Refer to ).

	Intermittent Malfunction (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).