DTC B2128: Steering Angle Sensor Signal Error

NOTE: Before troubleshooting, check the VSA system DTCs. If the VSA system is OK, do this troubleshooting.

Clear the DTCs with the HDS.
Turn the ignition switch OFF, and then back ON (II).
Turn the headlight switch ON.
Turn the steering wheel 90 degrees or more from the center position to the left or right, and repeat this five times.
Check for DTCs with the HDS.
Is DTC B2128 indicated?

YES - Go to step 6.

NO - Intermittent failure, the adaptive front lighting system is OK at this time. Check for loose or poor connections at the steering angle sensor connector and at the adaptive front lighting control unit connector.
Check the steering angle sensor (see DTC 27: STEERING ANGLE SENSOR ).
Is the steering angle sensor OK?

YES - Go to step 7.

NO - Faulty steering angle sensor, replace it.
Turn the ignition switch OFF.
Remove the driver's dashboard undercover (see DRIVER'S DASHBOARD UNDERCOVER REMOVAL/INSTALLATION ), and the driver's dashboard lower cover (see DRIVER'S DASHBOARD LOWER COVER REMOVAL/INSTALLATION ), then remove the steering column covers (see DRIVER'S DASHBOARD LOWER COVER REMOVAL/INSTALLATION ).
Disconnect the steering angle sensor 5P connector.
Disconnect the adaptive front lighting control unit 40P connector.
Disconnect the VSA modulator-control unit 47P connector.
Check for continuity between body ground and adaptive front lighting control unit 40P connector terminals No. 17, No. 18, and No. 38 individually.

Fig 1: Checking Continuity Between Body Ground And Terminals No. 17, No. 18, And No. 38
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Repair a short to ground in the wire.

NO - Go to step 13.
Check for continuity between steering angle sensor 5P connector terminals No. 2, No. 3, and No. 4 and adaptive front lighting control unit 40P connector terminals No. 17, No. 18, and No. 38 respectively.

Fig 2: Checking Continuity Between Terminals No. 2, No. 3, And No. 4 And Terminals No. 17, No. 18, And No. 38
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Faulty adaptive front lighting control unit, replace it and do the adaptive front lighting control unit learning procedure (see ADAPTIVE FRONT LIGHTING CONTROL UNIT LEARNING PROCEDURE ).

NO - Repair an open in the wire.