DTC B1128: Driver's Door Remote Switch Input Circuit Malfunction (Simultaneous Input Of Lock and Unlock Signal)

NOTE: If you are troubleshooting multiple DTC's, be sure to follow the instruction B-CAN System Diagnosis Test Mode A. (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A )

Clear the DTCs with the HDS.
Turn the ignition switch to LOCK (0) and then back to ON (II).
Lock and unlock the driver's door several times with the driver's door lock switch.
Check for DTCs with the HDS.
Is DTC B1128 indicated?

YES - Go to step 5.

NO - Intermittent failure, the system is OK at this time. Check for loose or poor connections.
With the driver's door lock switch in the neutral position, select KEYLESS from the HDS and enter the DATA LIST.
Check the ON/OFF information of the DRIVER'S DOOR LOCK SWITCH (LOCK) and DRIVER'S DOOR LOCK SWITCH (UNLOCK) in the DATA LIST.
Are both information indicators OFF?

YES - Faulty MICU, replace the under-dash fuse/relay box:
- For USA model (see USA MODELS ).
- For Canada model (see CANADA MODELS ).
NO - Go to step 7.
Disconnect the power window master switch connector.
Check the ON/OFF information of the DRIVER'S DOOR LOCK SWITCH (LOCK) and DRIVER'S DOOR LOCK SWITCH (UNLOCK) in the DATA LIST.
Are both information indicators OFF?

YES - Faulty door lock switch; replace the power window master switch.

NO - Go to step 9.
Turn the ignition switch to LOCK (0).
Disconnect under-dash fuse/relay box connector E (12P).
Check for continuity between under-dash fuse/relay box connector E (12P) terminals No. 8 (LOCK) and No. 1 (UNLOCK) and body ground individually.
Is there continuity?

YES - Repair short to ground in the LOCK or UNLOCK wire.

NO - Go to step 15.

Fig 1: Checking Continuity Between Under-Dash Fuse/Relay Box Connector E (12P) Terminals No. 8, No. 1 & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Turn the ignition switch to LOCK (0).
Disconnect the power window master switch connector.
Disconnect under-dash fuse/relay box connector E (12P).
Check for continuity between under-dash fuse/relay box connector E (12P) terminals No. 8 (LOCK) and No. 1 (UNLOCK).
Is there continuity?

YES - Repair short in the wire between the LOCK and UNLOCK wires.

NO - Faulty MICU, replace the under-dash fuse/relay box:
- For USA model (see USA MODELS ).
- For Canada model (see CANADA MODELS ).
Fig 2: Checking Continuity Between Under-Dash Fuse/Relay Box Connector E (12P) Terminals No. 8 & No. 1
Courtesy of AMERICAN HONDA MOTOR CO., INC.