DTC : B1127

DTC B1127  : Driver's door lock key cylinder switch malfunction

DTC (Door Multiplex Control Unit)

NOTE:  If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A - Go to: Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks .

1. Problem verification (driver's door key cylinder switch in the neutral position)

   -1. Check the parameter(s) below with the HDS.

   Signal	Current conditions
   	Values	Unit
   Driver's Door Key Cylinder Switch (LOCK)
   Driver's Door Key Cylinder Switch (UNLOCK)

   Is either information indicator ON?

   YES 

   Go to step 4.

   NO 

   Go to step 2.

2. Problem verification (driver's door key cylinder switch in the lock position)

   -1. With the driver's door key cylinder in the lock position, check the parameter(s) below with the HDS.

   Signal	Current conditions
   	Values	Unit
   Driver's Door Key Cylinder Switch (LOCK)
   Driver's Door Key Cylinder Switch (UNLOCK)

   Are both information indicators ON?

   YES 

   Go to step 3.

   NO 

   Intermittent failure, the system is OK at this time.

3. Shorted wire check (DR K/CYL LOCK line)

   -1. Turn the vehicle to the OFF (LOCK) mode.

   - 2. Disconnect the following connector.

   Driver's door latch 10P connector

   - 3. Connect terminals A and B with a jumper wire.

   Terminal A	Driver's door latch 10P connector No. 9
   Terminal B	Body ground

   Courtesy of HONDA, U.S.A., INC.

   - 4. Check the parameter(s) below with the HDS.

   Signal	Current conditions
   	Values	Unit
   Driver's Door Key Cylinder Switch (LOCK)
   Driver's Door Key Cylinder Switch (UNLOCK)

   Are both information indicators ON?

   YES 

   Repair a short between the wires.

   NO 

   The DR K/CYL LOCK wire is OK. Faulty driver's door key cylinder switch; replace the driver's Door Latch - Removal and Installation .

4. Determine possible failure area (driver's door latch, others)

   -1. Turn the vehicle to the OFF (LOCK) mode.

   - 2. Disconnect the following connector.

   Driver's door latch 10P connector

   - 3. Check the parameter(s) below with the HDS.

   Signal	Current conditions
   	Values	Unit
   Driver's Door Key Cylinder Switch (LOCK)
   Driver's Door Key Cylinder Switch (UNLOCK)

   Is either information indicator ON?

   YES 

   Go to step 5.

   NO 

   Faulty driver's door key cylinder switch; replace the driver's Door Latch - Removal and Installation .

5. Shorted wire check (DR K/CYL UNLOCK, DR K/CYL LOCK lines)

   -1. Turn the vehicle to the OFF (LOCK) mode.

   - 2. Disconnect the following connector.

   Power window master switch 37P connector

   - 3. Check for continuity between test points 1 and 2 individually.

   Test condition	Vehicle OFF (LOCK) mode Driver's door latch 10P connector: disconnected Power window master switch 37P connector: disconnected
   Test point 1	Power window master switch 37P connector No. 34 - Refer to: Power Window Master Switch Connector for Inputs and Outputs (2016 2017 2018) or Power Window Master Switch Connector for Inputs and Outputs (2019 2020 2021) .
   Test point 2	Body ground

   Test point 1	Power window master switch 37P connector No. 35 - Refer to: Power Window Master Switch Connector for Inputs and Outputs (2016 2017 2018) or Power Window Master Switch Connector for Inputs and Outputs (2019 2020 2021) .
   Test point 2	Body ground

   Is there continuity?

   YES 

   Repair a short to ground in the wire.

   NO 

   The DR K/CYL UNLOCK and DR K/CYL LOCK wires are OK. Replace the Power Window Master Switch - Removal and Installation .