Inspection Procedure

HINT:

When troubleshooting in accordance with the PROBLEM SYMPTOMS TABLE, be sure to follow the table before replacing the ECM.

1. CHOOSE DIAGNOSIS METHOD 
   1. Choose the diagnosis method.
      PROBLEM SYMPTOMS CHART
      
      

      Method	Proceed to
      Using intelligent tester	A
      Not using intelligent tester	B

   B: Go to step   3 

   A: GO TO NEXT STEP 

2. READ VALUE ON INTELLIGENT TESTER 
   1. Connect the intelligent tester to the DLC3.
   2. Turn the ignition switch to the ON position, and turn the intelligent tester main switch on.
   3. Select the item "STP LIGHT SW M", "STP LIGHT SW S1" or "STP LIGHT SW D2" in the DATA LIST, and read its value display on the intelligent tester.
   4. Check that the stop light come on when the brake pedal is depressed, and goes off when the brake pedal is released.

      ECM (Cruise Control) 

      DATA LIST
      
      

      Item	Measurement Item / Display (Range)	Normal Condition	Diagnostic Note
      STP LIGHT SW2 M	Stop light SW signal (Main CPU)/ ON or OFF	ON: Brake pedal depressed OFF: Brake pedal released	-
      STP LIGHT SW1 M	Stop light SW signal (Sub CPU) / ON or OFF	ON: Brake pedal depressed OFF: Brake pedal released	-
      STP LIGHT SW2 S	Stop light SW signal (Sub CPU) / ON or OFF	ON: Brake pedal depressed OFF: Brake pedal released	-

      OK: When the brake pedal is operated, the display changes as shown above. 

      Result 

      RESULT REFERENCE
      
      

      Result	Proceed to
      OK (When troubleshooting In accordance with the DTC CHART.)	A
      OK (When troubleshooting in accordance with the PROBLEM SYMPTOMS TABLE.)	B
      NG	C

   A: REPLACE ECM 

   B: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE 

   C: GO TO NEXT STEP 

3. INSPECT STOP LIGHT SWITCH ASSEMBLY 
   1. Disconnect the S8 stop light switch connector.
   2. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      STOP LIGHT SWITCH ASSEMBLY STANDARD RESISTANCE SPECIFICATIONS
      
      

      Tester Connection	Condition	Specified Condition
      1-2	Switch pin free	Below 1 Ω
      3-4	Switch pin free	10 kΩ or higher
      1-2	Switch pin pushed In	10 kΩ or higher
      3-4	Switch pin pushed in	Below 1 Ω

   NG: REPLACE STOP LIGHT SWITCH ASSEMBLY 

   Fig 1: Inspecting Stop Light Switch Assembly

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: GO TO NEXT STEP 

4. CHECK WIRE HARNESS (STOP LIGHT SWITCH - BATTERY) 
   1. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      WIRE HARNESS STANDARD VOLTAGE SPECIFICATIONS
      
      

      Tester Connection	Condition	Specified Condition
      2 - Body ground	Always	10 to 14 V
      3 - Body ground	Ignition switch ON	10 to 14 V

   NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

   Fig 2: Checking Wire Harness (Stop Light Switch - Battery)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: GO TO NEXT STEP 

5. CHECK WIRE HARNESS (ECM - STOP LIGHT SWITCH) 
   1. Reconnect the S8 stop light switch connector.
   2. Disconnect the E4 and E5 connectors from the ECM.
   3. Turn the ignition switch to the ON position.
   4. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      WIRE HARNESS STANDARD VOLTAGE SPECIFICATIONS
      
      

      Tester Connection	Condition	Specified Condition
      E4-16 (ST1-)-Body ground	Brake pedal depressed	Below 1 V
      E4-16 (ST1-)-Body ground	Brake pedal released	10 to 14 V
      E5-4 (STP) - Body ground	Brake pedal depressed	10 to 14 V
      E5-4 (STP) - Body ground	Brake pedal released	Below 1 V

   NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

   Fig 3: Disconnecting E4 And E5 Connectors From ECM

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: REPLACE ECM