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 - Refer to: Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks (2014 2015 2016) or Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks (2017 2018 2019 2020)

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)

   Signal	Current conditions
   	Values	Unit
   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 (LF KEY UNLOCK to LF KEY 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	Power window master switch 37P connector No. 35 (PNK)
   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)

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

   Are both information indicators ON?

   YES 

   Repair a short between the wires.

   NO 

   The LF KEY UNLOCK to LF KEY LOCK wire is OK. Faulty driver's door key cylinder switch; replace the driver's door latch .

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 .

5. Shorted wire check (LF KEY UNLOCK, LF KEY 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 circuit	LF KEY UNLOCK
   Test point 1	Power window master switch 37P connector No. 34 (BRN)
   Test point 2	Body ground

   Test circuit	LF KEY LOCK
   Test point 1	Power window master switch 37P connector No. 35 (PNK)
   Test point 2	Body ground

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

   Is there continuity?

   YES 

   Repair a short to ground in the wire.

   NO 

   The LF KEY UNLOCK and LF KEY LOCK wires are OK. Replace the power window master switch .