DTC B1318: Short in Manual Switch Circuit [03/2017 - ]: 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 / Active Rear Wing / Data List.
5. Read the Data List according to the display on the Techstream.

   Body Electrical > Active Rear Wing > Data List 

   Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
   Manual Switch	No. 4 combination switch assembly (Spoiler control switch) condition	OFF or ON	OFF: No. 4 combination switch assembly (Spoiler control switch) not pressed ON: No. 4 combination switch assembly (Spoiler control switch) pressed	-

   Body Electrical > Active Rear Wing > Data List 

   Tester Display
   Manual Switch

   OK

   The Techstream display changes according to the No. 4 combination switch assembly (spoiler control switch).

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE SPOILER CONTROL ECU ASSEMBLY. Refer to  REMOVAL [03/2017 - 05/2023]  , or refer to  REMOVAL [05/2023 - ] 

Result: 

NG 

See step  2

1. Remove the No. 4 combination switch assembly (spoiler control switch).

   Refer to REMOVAL [03/2017 - 05/2023] , or refer to REMOVAL [05/2023 - ]

2. Inspect the No. 4 combination switch assembly (spoiler control switch).

   Refer to INSPECTION [03/2017 - ]

   Result

   Result
   OK
   NG

Result: 

NG 

REPLACE NO. 4 COMBINATION SWITCH ASSEMBLY (SPOILER CONTROL SWITCH). Refer to  REMOVAL [03/2017 - 05/2023]  , or refer to  REMOVAL [05/2023 - ] 

Result: 

OK 

See step  3

1. Disconnect the X79 spoiler control ECU assembly connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   X79-14 (MSW) or P78-1(ECU) - Body ground	Always	10 kΩ or higher

   Result

   Result
   OK
   NG

Result: 

OK 

REPLACE SPOILER CONTROL ECU ASSEMBLY. Refer to  REMOVAL [03/2017 - 05/2023]  , or refer to  REMOVAL [05/2023 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR