B1127

DTC Troubleshooting: B1127

DTC B1127:

Driver's Door Key Cylinder Switch Signal Error

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).

3. Operate the driver's door key cylinder several 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 system is OK at this time. Check for loose or poor connections.�

5. With the driver's door key cylinder in the neutral position, select SECURITY 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 7.

NO -

Go to step 8.

7. Turn the driver's door key cylinder to the LOCK and UNLOCK positions with the ignition key and 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.

Is the DRIVER'S DOOR KEY CYLINDER SWITCH (LOCK) (DRIVER'S DOOR KEY CYLINDER SWITCH (UNLOCK)) information indicator ON when the key cylinder is in the LOCK (UNLOCK) position, and OFF when the key is returned to the neutral position?

YES -

Substitute the door multiplex control unit and retest.�

NO -

Faulty driver's door key cylinder switch or short to ground on the WHT/BLU and/or WHT wire.�

8. Disconnect the driver's door key cylinder switch 3P connector.

9. 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.�

NO -

Go to step 10.

10. Turn the ignition switch to LOCK (0).

11. Disconnect the driver's door multiplex control unit 23P connector.

12. Check for continuity between driver's door key cylinder switch 3P connector terminals No. 3 (LOCK) and No. 1 (UNLOCK) and body ground individually.





Is there continuity?

YES -

Repair a short in the WHT/BLU (LOCK) or WHT (UNLOCK) wire.�

NO -

Faulty door multiplex control unit; replace the power window master switch Power Window Master Switch Replacement.�