B1488

DTC B1488: Passenger's Air Bag OFF Indicator Light Drive Circuit System Fault 2.

Air Bag OFF Indicator Light Drive Circuit:

CAUTION:
If 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 ignition switch (IG1).
- 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.

DTC SET CONDITIONS
- This DTC is set under one of the following cases while the SRS-ECU is monitoring the passenger's air bag OFF indicator light drive circuit:
- When a short circuit occurs in the passenger's air bag OFF indicator light drive circuit.
- When a malfunction is detected in the output transistor inside the SRS-ECU.

However, if the vehicle condition returns to normal, DTC B1488 will be automatically erased, and the passenger's air bag OFF indicator light will go out.

TROUBLESHOOTING HINTS
- Damaged wiring harnesses or connectors
- Malfunction of the SRS-ECU

DIAGNOSIS

Required Special Tools:
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: MUT-III USB Cable
- MB991910: MUT-III Main Harness A (Vehicles with CAN Communication System)

STEP 1. Using scan tool MB991958, diagnose the CAN bus line.

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.




1. Connect scan tool MB991958. Refer to "How to connect the scan tool." Reading Diagnostic Trouble Codes
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?

YES: Go to Step 2.

NO: Repair the CAN bus line (Refer to Diagnosis). Component Tests and General Diagnostics




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.

Q: Is the DTC set?

YES: Check the passenger's air bag OFF indicator light drive circuit system (Refer to DTC B1489).

NO: There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to How to Cope with Intermittent Malfunction).