B1509

DTC B1509: Improper Installation of SRS-ECU

CAUTION:
If DTC B1509 is set in the SRS-ECU, always diagnose the CAN main bus line.

DTC SET CONDITIONS

This DTC is set when an SRS-ECU, designed only for the driver's air bag, is installed on the vehicle, which has both driver's and passenger's air bags. However, if the vehicle condition return to normal, DTC number B1509 will be automatically erased, and the SRS warning light will switch off.

TROUBLESHOOTING HINTS

- Malfunction of the SRS-ECU

DIAGNOSIS

Required Special Tools:

- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A

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





(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 Reading and Clearing 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 CAN Bus Diagnostics Chart).

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 B1509 set?

YES Replace the SRS-ECU (Refer to Service and Repair).

NO There is an intermittent malfunction such as poor engaged connector(s) or open circuit How to Cope With Intermittent Malfunctions).