B1550

DTC B1550: SRS warning Light Drive Circuit System Fault 2 (Passenger's seat belt warning Light Drive Circuit Malfunction).

SRS Warning Light Drive Circuit:

CIRCUIT OPERATION
- Power for the SRS warning light is supplied from the ignition switch (IG1).
- The SRS warning 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 warning light drive circuit:
- When a short circuit occurs in the warning 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 B1550 will be automatically erased, and the SRS warning light will go out.

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

DIAGNOSIS

Required Special Tool:
- 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)

STEP 1. 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: Go to Step 2.

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

STEP 2. Check the SRS warning light drive circuit system SRS Warning Light Check

Q: Is the SRS warning light drive circuit normal?

YES: Erase the diagnostic trouble code memory and check the diagnostic trouble code. If DTC B1551 sets, replace the SRS-ECU. Then go to Step 3.

NO: Replace the combination meter (Refer to Combination Meter Assembly). Then go to Step 3.




STEP 3. Recheck for diagnostic trouble code.

Q: Is DTC B1550 set?

YES: There is no action to be taken.

NO: The procedure is complete.