B1127

DTC Troubleshooting: B1127

DTC B1127: Driver's Door Key Cylinder Switch Malfunction

NOTE: If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A. Troubleshooting - B-CAN System Diagnosis Test Mode A

1. Clear the DTCs with the HDS.

2. Turn the ignition switch to LOCK (0) and then back to ON (II), or press the engine start/stop button to select the OFF mode and then the ON mode.

3. Insert the ignition key into the driver's door key cylinder switch, and turn the key to the LOCK and UNLOCK positions 10 times.

4. Check for DTCs with the HDS.

Is DTC B1127 indicated?
YES - Go to step 5.

NO - Intermittent failure, the driver's door key cylinder switch system is OK at this time.


5. With the driver's door key cylinder in the neutral position, select KEYLESS with the HDS, and enter DATA LIST.

6. Check the ON/OFF information of the DRIVER'S DOOR KEY CYLINDER SWITCH (LOCK) and DRIVER'S DOOR KEY CYLINDER SWITCH (UNLOCK) in the DATA LIST.

Are both information indicators OFF?
YES - Go to step 12.

NO - Go to step 7.


7. Disconnect the driver's door lock actuator 10P connector.

8. Check the ON/OFF information of the DRIVER'S DOOR KEY CYLINDER SWITCH (LOCK) and DRIVER'S DOOR KEY CYLINDER SWITCH (UNLOCK) in the DATA LIST.

Are both information indicators OFF?
YES - Faulty driver's door key cylinder switch; replace the driver's door lock actuator.

NO - Go to step 9.


9. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

10. Disconnect the door multiplex control unit 37P connector.

11. Check for continuity between body ground and the door multiplex control unit 37P connector terminals No. 28 and No. 29.

Is there continuity?
YES - Repair short to ground in the LOCK or UNLOCK wire.

NO - Replace the power window master switch. Power Window Master Switch Replacement






12. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

13. Disconnect the driver's door lock actuator 10P connector.

14. Disconnect the door multiplex control unit 37P connector.

15. Check for continuity between the door multiplex control unit 37P connector terminals No. 28 and No. 29.

Is there continuity?
YES - Repair short between the LOCK and UNLOCK wires.

NO - Substitute a known-good power window master switch. If the symptom goes away, replace the original power window master switch. If not, replace the driver's door lock actuator.