B1BAA

DTC B1BAA: Occupant Classification-ECU Configuration Mismatch

CAUTION:

- If the DTC B1BAA is set, diagnose the CAN main bus lines.
- When replacing the ECU, always check that the communication circuit is normal.

DTC SET CONDITION

If the information data and coding data on occupant classification-ECU do not suit. The SRS-ECU sets the DTC B1BAA

TROUBLESHOOTING HINTS

- The CAN bus line may be defective
- The ETACS-ECU may be defective
- The occupant classification-ECU may be defective
- The SRS-ECU may be defective

DIAGNOSIS

Required Special Tools:

- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicles Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)

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. Using scan tool MB991958, read the ETACS-ECU diagnostic trouble code

Check if DTC U0331, B1761, B222C, B2206 or B2215 is set to the ETACS-ECU.

Q. Is the DTC set?

YES Troubleshoot the ETACS-ECU Electronic Time and Alarm Control System (ETACS)).
Then go to Step 4.
NO Go to Step 3.
STEP 3. Using scan tool MB991958, read the occupant classification-ECU diagnostic trouble code

Check if DTC B1B91 is set to the occupant classification-ECU.

Q. Is the DTC set?

YES Troubleshoot the occupant classification-ECU (Refer to Supplemental Restraint System). Then go to Step 4.
NO Go to Step 4.
STEP 4. Recheck for diagnostic trouble code.

Check again if the DTC is set to the SRS-ECU.

(1)Erase the DTC.

(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.

(3)Check if DTC is set.

(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the DTC 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).