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DTC B1488: Passenger’s Air Bag OFF Indicator Light (Short Circuit between Circuit Terminal)
 
 

cautionIf DTC B1488 is set in the SRS-ECU, always diagnose the CAN main bus line.
 
 
CIRCUIT OPERATION
  • Power for the passenger’s air bag OFF indicator light is supplied from the fusible link (34).
  • The passenger’s air bag OFF indicator light illuminates when the ignition switch is turned to the "ON" position and goes out after approximately seven seconds if there is not a malfunction in the SRS system. In the following situations, the indicator will stay on to show that the passenger’s (front) air bag is not operational.
    • The occupant is determined to be less than 66 lbs (30 kg) by the occupant classification-ECU.
    • The front passenger’s seat is not occupied.
 
 
DTC SET CONDITIONS
This DTC will be set if the passenger’s air bag OFF indicator light driving circuit is short to ground. If the vehicle condition returns to normal, DTC B1488 will be automatically erased, and the warning light will go out.
 
 
TROUBLESHOOTING HINTS
  • Damaged wiring harnesses or connectors
  • Malfunction of the SRS-ECU
  • Malfunction of the passenger’s air bag OFF indicator light
 
 
DIAGNOSIS
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.
(1)
cautionTo 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.
Is the CAN bus line found to be normal?
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C, Diagnosis ).
 
STEP 2. Recheck for diagnostic trouble code.
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.
Is the DTC set?
Go to Step 3.
There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
 
STEP 3. Check the passenger’s air bag OFF indicator light.
It is checked whether the passenger’s air bag OFF indicator light is normal (Refer to ).
Is the check result normal?
Go to Step 4.
Replace the hazard indicator assembly (Refer to GROUP 52A - Instrument Center Panel ).
 
STEP 4. Resistance measurement at the C-126 SRS-ECU connector.
(1) Disconnect the negative battery terminal.
(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-126 SRS-ECU connector.
(3) Disconnect the C-246 hazard indicator assembly connector.
(4) Take the measurements below at the SRS-ECU harness side connector. It should be open circuit.
  • Continuity between terminal No.13 and body ground.
Is it open circuit?
Go to Step 5.
Repair the wiring harness between the C-126 SRS-ECU connector terminal No. 13 and the C-246 hazard indicator assembly connector terminal No.11. Then go to Step 6.
 
STEP 5. Resistance measurement at the C-246 hazard indicator assembly connector.
(1) Disconnect the negative battery terminal.
(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-126 SRS-ECU connector.
(3)
cautionDo not insert a probe into the terminal from its front side directly, as the connector contact pressure may be weakened.
Take the following measurements at the backside of the C-246 hazard indicator assembly side connector (harness side).
  • Continuity between terminal No.11 and body ground.
It should be open circuit.
Is it open circuit?
Go to Step 6.
Replace SRS-ECU (Refer to ).
 
STEP 6. Recheck for diagnostic trouble code.
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.
Is DTC B1488 set?
Replace SRS-ECU (Refer to ).
There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).