DTC U0242: Lost Communication With Headlamp Control Module "B" [09/2020 - ]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / HL AutoLeveling / Trouble Codes.
5. Clear the DTCs.

   Body Electrical > HL AutoLeveling > Clear DTCs 

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  2

1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / HL AutoLeveling / Trouble Codes.
5. Check for DTCs.

   Body Electrical > HL AutoLeveling > Trouble Codes 

   OK

   DTC U0242 is not output.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2020 - 11/2021]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2021 - 09/2022]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2022 - ] 

Result: 

NG 

See step  3

1. Disconnect the A112 headlight ECU sub-assembly LH connector.
2. Disconnect the A110 headlight ECU sub-assembly RH connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A112-20 (LINL) - A110-20 (LINL)	Always	Below 1 Ω
   A112-20 (LINL) or A110-20 (LINL) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  4

1. Replace the headlight ECU sub-assembly RH with a new one.

   Refer to REMOVAL [09/2020 - ]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  5

1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / HL AutoLeveling / Trouble Codes.
5. Clear the DTCs.

   Body Electrical > HL AutoLeveling > Clear DTCs 

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  6

1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / HL AutoLeveling / Trouble Codes.
5. Check for DTCs.

   Body Electrical > HL AutoLeveling > Trouble Codes 

   OK

   DTC U0242 is not output.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

END (HEADLIGHT ECU SUB-ASSEMBLY RH WAS DEFECTIVE) 

Result: 

NG 

REPLACE HEADLIGHT ECU SUB-ASSEMBLY LH. Refer to  REMOVAL [09/2020 - ]