Key Reminder Warning System - Diagnostics: Pre-Check

1. When the driver side door is opened with the ignition key in the ACC or LOCK position, this system causes a buzzer to sound in order to warn the driver that the ignition key has not been removed.

1. Inspect the DLC3.

   HINT:

   The vehicle's ECM uses ISO 9141-2 for communication.

   The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 9141-2 format.

   Fig 1: Inspecting DLC3

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   DLC3
   
   

   Terminal	Connection Condition	Specified Condition
   7 (Bus + line) - 5 (Signal ground)	During communication	Pulse generation
   4 (Chassis ground) - Body ground	Constant	Below 1 Ω
   5 (Signal ground) - Body ground	Constant	Below 1 Ω
   16 (B+) - Body ground	Constant	9 to 14 V

   HINT:

   If the display shows UNABLE TO CONNECT TO VEHICLE when you have connected the cable of the hand-held tester to the DLC3, turned the ignition switch ON and operated the hand-held tester, there is a problem on the vehicle side or tester side.

   • If communication is normal when the tester is connected to another vehicle, inspect the DLC3 of the original vehicle.
   • If communication is still impossible when the tester is connected to another vehicle, the problem is probably in the tester itself, so consult the Service Department listed in the tester's instruction manual.
2. Check the battery voltage.

   Standard: 11 to 14 V 

   If voltage is below 11V, recharge the battery before proceeding.

1. Checking DTCs.
   1. Connect the hand-held tester to the DLC3.
      Fig 2: Connecting Hand-Held Tester To DLC3

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   2. Turn the ignition switch ON.
   3. Read DTCs by following the prompts on the tester screen.

   HINT:

   Refer to the hand-held tester operator's manual for further details.

1. Clearing the DTCs.
   1. Connect the hand-held tester to the DLC3.
   2. Turn the ignition switch ON.
   3. Erase the DTCs following the prompts on the tester screen.

   HINT:

   Refer to the hand-held tester operator's manual for further details.

HINT:

Using the DATA LIST displayed on the hand-held tester, you can read the value of the switch, sensor, actuator, etc. without parts removal. Reading the DATA LIST as the first step of troubleshooting is one way to shorten the labor time.

1. Connect the hand-held tester to the DLC3.
2. Turn the ignition switch ON.
3. Read the DATA LIST according to the display on the tester.

   Standard (Multiplex network body ECU): 

   DATA LIST
   
   

   Item	Measurement Item/Display (Range)	Normal Condition	Diagnostic Note
   KEY UNLK WRN SW	Key unlock warning switch signal/ON or OFF	ON: Key is in ignition key cylinder OFF: No key is in ignition key cylinder	-
   D DOR CTY SW	Driver's door courtesy switch signal/ON or OFF	ON: Driver side door is open OFF: Driver side door is closed	-