METER / GAUGE SYSTEM Speed Signal Circuit

DESCRIPTION

The combination meter assembly receives the vehicle speed signal from this circuit. The wheel speed sensors produce an output that varies according to the vehicle speed. The wheel speed sensor output is received by the skid control ECU assembly which uses this information to create the vehicle speed signal*a. The vehicle speed signal consists of pulses sent to the combination meter assembly from the skid control ECU assembly. To create this signal, 12 V is output from IG2 which is behind a resistor in the combination meter assembly. This voltage is sent to the skid control ECU assembly. The pulse signal is created by switching the transistor in the skid control ECU assembly on and off, making the voltage on the wire drop to 0 V. A similar system is used for the output of this signal from the combination meter assembly via terminal +S. A voltage of 12 V or 5 V is applied to terminal +S from each ECU or relay that is connected to this terminal. The transistor in the combination meter assembly is controlled by the signal from the skid control ECU assembly. When this transistor is turned on, this transistor makes the voltage supplied by the various ECUs (via their respective internal resistors) drop to 0 V. Each ECU connected to terminal +S of the combination meter assembly controls its respective system based on this pulse signal.

• *a: This vehicle speed signal is created by the skid control ECU assembly. There is no actual component that is referred to as the vehicle speed sensor. In addition, for some systems, vehicle speed information may be received via CAN communication.

WIRING DIAGRAM

PROCEDURE

1. INSPECT ECU TERMINAL VOLTAGE (INPUT VOLTAGE)

   
   
   1. 

      *a	Front view of wire harness connector (to Combination Meter Assembly)

      Disconnect the K3 combination meter assembly connector.

   2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition K3-19 (+S) - Body ground Power switch on (IG) 4.5 to 14 V

      Tech Tips

      If any of the ECUs specified in the wiring diagram supplies power to the combination meter assembly, the combination meter assembly will output a waveform.

      Result
      Result Proceed to OK A NG (w/ Navigation System or Audio and Visual System with Parallel Parking Assist Function) B NG (w/ Audio and Visual System without Parallel Parking Assist Function) C NG (w/o Navigation System and Audio and Visual System) D

   
   

   B

   CHECK HARNESS AND CONNECTOR (EACH ECU - COMBINATION METER ASSEMBLY) Click here

   C

   CHECK HARNESS AND CONNECTOR (EACH ECU - COMBINATION METER ASSEMBLY) Click here

   D

   CHECK HARNESS AND CONNECTOR (EACH ECU - COMBINATION METER ASSEMBLY) Click here

   A

2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE)

   
   

   1. Reconnect the K3 combination meter assembly connector.

   2. 

      *a	Front view of wire harness connector (to Skid Control ECU Assembly)

      Disconnect the A24 skid control ECU assembly connector.

   3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition A24-23 (SP1) - Body ground Power switch on (IG) 11 to 14 V

      Result
      Proceed to OK NG

   
   

   NG

   CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - SKID CONTROL ECU ASSEMBLY) Click here

   OK

3. INSPECT SKID CONTROL ECU ASSEMBLY (INPUT WAVEFORM)

   
   
   1. 

      *a	Component with harness connected (Combination Meter Assembly)

      Check the input waveform.

      
      

      1. Reconnect the A24 skid control ECU assembly connector.

      2. Remove the combination meter assembly with the connector(s) still connected.

      3. Connect an oscilloscope to terminal K3-20 (SI) and body ground.

      4. Turn the power switch on (IG).

      5. Turn a wheel slowly.

      6. Check the signal waveform according to the condition(s) in the table below.

         Item	Condition
         Tool setting	5 V/DIV., 20 ms./DIV.
         Vehicle condition	Power switch on (IG), wheel being rotated

         OK
         The waveform is similar to that shown in the illustration.

         Tech Tips

         When the system is functioning normally, one wheel revolution generates 4 pulses. As the vehicle speed increases, the width indicated by (A) in the illustration narrows.

      Result
      Proceed to OK NG

   
   

   OK

   REPLACE COMBINATION METER ASSEMBLY Click here

   NG

   REPLACE SKID CONTROL ECU ASSEMBLY for LHD: Click here REPLACE SKID CONTROL ECU ASSEMBLY for RHD: Click here

4. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - SKID CONTROL ECU ASSEMBLY)

   
   

   1. Disconnect the K3 combination meter assembly connector.

   2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition K3-20 (SI) - A24-23 (SP1) Always Below 1 Ω K3-20 (SI) - Body ground Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   OK

   REPLACE COMBINATION METER ASSEMBLY Click here

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

5. CHECK HARNESS AND CONNECTOR (EACH ECU - COMBINATION METER ASSEMBLY)

   
   

   1. Disconnect the K137 certification ECU (smart key ECU assembly) connector.

   2. Disconnect the P23 stereo component amplifier assembly connector.

   3. Disconnect the K58 radio receiver assembly connector.

   4. Disconnect the K158 DCM (telematics transceiver) connector*1.

   5. Disconnect the K145 vehicle approaching speaker controller connector*2.

   6. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition K3-19 (+S) - Body ground Always 10 kΩ or higher

      
      

      • *1: w/ Manual (SOS) Switch

      • *2: w/ Vehicle Proximity Notification System

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

6. INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY (SHORT CIRCUIT IN STEREO COMPONENT AMPLIFIER ASSEMBLY)

   
   

   1. Connect the K137 certification ECU (smart key ECU assembly) connector.

   2. Connect the K58 radio receiver assembly connector.

   3. Connect the K158 DCM (telematics transceiver) connector*1.

   4. Connect the K145 vehicle approaching speaker controller connector*2.

      
      

      • *1: w/ Manual (SOS) Switch

      • *2: w/ Vehicle Proximity Notification System

   5. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition K3-19 (+S) - Body ground Power switch on (IG) 4.5 to 14 V

      Tech Tips

      If the result is as specified, there may be a short circuit in the stereo component amplifier assembly.

      Result
      Proceed to OK NG

   
   

   OK

   REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY Click here

   NG

7. INSPECT RADIO RECEIVER ASSEMBLY (SHORT CIRCUIT IN RADIO RECEIVER ASSEMBLY)

   
   

   1. Disconnect the K58 radio receiver assembly connector.

   2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition K3-19 (+S) - Body ground Power switch on (IG) 4.5 to 14 V

      Tech Tips

      If the result is as specified, there may be a short circuit in the radio receiver assembly.

      Result
      Proceed to OK NG

   
   

   OK

   REPLACE RADIO RECEIVER ASSEMBLY w/ Navigation System: Click here REPLACE RADIO RECEIVER ASSEMBLY w/ Audio and Visual System: Click here

   NG

   GO TO STEP 12 Click here

8. CHECK HARNESS AND CONNECTOR (EACH ECU - COMBINATION METER ASSEMBLY)

   
   

   1. Disconnect the K137 certification ECU (smart key ECU assembly) connector.

   2. Disconnect the K72 radio receiver assembly connector.

   3. Disconnect the P24 stereo component amplifier assembly connector*1.

   4. Disconnect the K158 DCM (telematics transceiver) connector*2.

   5. Disconnect the K145 vehicle approaching speaker controller connector*3.

   6. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition K3-19 (+S) - Body ground Always 10 kΩ or higher

      
      

      • *1: for 10 Speakers

      • *2: w/ Manual (SOS) Switch

      • *3: w/ Vehicle Proximity Notification System

      Result
      Result Proceed to OK (for 10 Speakers) A OK (except 10 Speakers) B NG C

   
   

   B

   INSPECT RADIO RECEIVER ASSEMBLY (SHORT CIRCUIT IN RADIO RECEIVER ASSEMBLY) Click here

   C

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   A

9. INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY (SHORT CIRCUIT IN STEREO COMPONENT AMPLIFIER ASSEMBLY)

   
   

   1. Connect the K137 certification ECU (smart key ECU assembly) connector.

   2. Connect the K72 radio receiver assembly connector.

   3. Connect the K158 DCM (telematics transceiver) connector*1.

   4. Connect the K145 vehicle approaching speaker controller connector*2.

      
      

      • *1: w/ Manual (SOS) Switch

      • *2: w/ Vehicle Proximity Notification System

   5. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition K3-19 (+S) - Body ground Power switch on (IG) 4.5 to 14 V

      Tech Tips

      If the result is as specified, there may be a short circuit in the stereo component amplifier assembly.

      Result
      Proceed to OK NG

   
   

   OK

   REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY Click here

   NG

10. INSPECT RADIO RECEIVER ASSEMBLY (SHORT CIRCUIT IN RADIO RECEIVER ASSEMBLY)

    
    

    1. Disconnect the K72 radio receiver assembly connector.

    2. Measure the voltage according to the value(s) in the table below.

       Standard Voltage
       Tester Connection Condition Specified Condition K3-19 (+S) - Body ground Power switch on (IG) 4.5 to 14 V

       Tech Tips

       If the result is as specified, there may be a short circuit in the radio receiver assembly.

       Result
       Proceed to OK NG

    
    

    OK

    REPLACE RADIO RECEIVER ASSEMBLY Click here

    NG

    GO TO STEP 12 Click here

11. INSPECT RADIO RECEIVER ASSEMBLY (SHORT CIRCUIT IN RADIO RECEIVER ASSEMBLY)

    
    

    1. Connect the K137 certification ECU (smart key ECU assembly) connector.

    2. Connect the K158 DCM (telematics transceiver) connector*1.

    3. Connect the K145 vehicle approaching speaker controller connector*2.

       
       

       • *1: w/ Manual (SOS) Switch

       • *2: w/ Vehicle Proximity Notification System

    4. Measure the voltage according to the value(s) in the table below.

       Standard Voltage
       Tester Connection Condition Specified Condition K3-19 (+S) - Body ground Power switch on (IG) 4.5 to 14 V

       Tech Tips

       If the result is as specified, there may be a short circuit in the radio receiver assembly.

       Result
       Proceed to OK NG

    
    

    OK

    REPLACE RADIO RECEIVER ASSEMBLY Click here

    NG

12. CONFIRM MODEL

    
    

    1. Choose the model to be inspected.

       Result
       Result Proceed to w/ Vehicle Proximity Notification System w/ Manual (SOS) Switch A w/o Manual (SOS) Switch B w/o Vehicle Proximity Notification System w/ Manual (SOS) Switch C w/o Manual (SOS) Switch D

    
    

    B

    GO TO STEP 18 Click here

    C

    INSPECT DCM (TELEMATICS TRANSCEIVER) (SHORT CIRCUIT IN STEREO COMPONENT AMPLIFIER ASSEMBLY) Click here

    D

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    A

13. INSPECT DCM (TELEMATICS TRANSCEIVER) (SHORT CIRCUIT IN STEREO COMPONENT AMPLIFIER ASSEMBLY)

    
    

    1. Disconnect the K158 DCM (telematics transceiver) connector.

    2. Measure the voltage according to the value(s) in the table below.

       Standard Voltage
       Tester Connection Condition Specified Condition K3-19 (+S) - Body ground Power switch on (IG) 4.5 to 14 V

       Tech Tips

       If the result is as specified, there may be a short circuit in the DCM (telematics transceiver).

       Result
       Proceed to OK NG

    
    

    OK

    REPLACE DCM (TELEMATICS TRANSCEIVER) Click here

    NG

    GO TO STEP 18 Click here

14. INSPECT DCM (TELEMATICS TRANSCEIVER) (SHORT CIRCUIT IN STEREO COMPONENT AMPLIFIER ASSEMBLY)

    
    

    1. Disconnect the K158 DCM (telematics transceiver) connector.

    2. Measure the voltage according to the value(s) in the table below.

       Standard Voltage
       Tester Connection Condition Specified Condition K3-19 (+S) - Body ground Power switch on (IG) 4.5 to 14 V

       Tech Tips

       If the result is as specified, there may be a short circuit in the DCM (telematics transceiver).

       Result
       Proceed to OK NG

    
    

    OK

    REPLACE DCM (TELEMATICS TRANSCEIVER) Click here

    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

15. CHECK HARNESS AND CONNECTOR (EACH ECU - COMBINATION METER ASSEMBLY)

    
    

    1. Disconnect the K137 certification ECU (smart key ECU assembly) connector.

    2. Disconnect the K158 DCM (telematics transceiver) connector*1.

    3. Disconnect the K145 vehicle approaching speaker controller connector*2.

    4. Measure the resistance according to the value(s) in the table below.

       Standard Resistance
       Tester Connection Condition Specified Condition K3-19 (+S) - Body ground Always 10 kΩ or higher

       
       

       • *1: w/ Manual (SOS) Switch

       • *2: w/ Vehicle Proximity Notification System

       Result
       Proceed to OK NG

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

16. CONFIRM MODEL

    
    

    1. Choose the model to be inspected.

       Result
       Result Proceed to w/ Vehicle Proximity Notification System w/ Manual (SOS) Switch A w/o Manual (SOS) Switch B w/o Vehicle Proximity Notification System w/ Manual (SOS) Switch C w/o Manual (SOS) Switch D

    
    

    B

    INSPECT VEHICLE APPROACHING SPEAKER CONTROLLER (SHORT CIRCUIT IN STEREO COMPONENT AMPLIFIER ASSEMBLY) Click here

    C

    INSPECT DCM (TELEMATICS TRANSCEIVER) (SHORT CIRCUIT IN STEREO COMPONENT AMPLIFIER ASSEMBLY) Click here

    D

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    A

17. INSPECT DCM (TELEMATICS TRANSCEIVER) (SHORT CIRCUIT IN STEREO COMPONENT AMPLIFIER ASSEMBLY)

    
    

    1. Connect the K137 certification ECU (smart key ECU assembly) connector.

    2. Connect the K145 vehicle approaching speaker controller connector.

    3. Measure the voltage according to the value(s) in the table below.

       Standard Voltage
       Tester Connection Condition Specified Condition K3-19 (+S) - Body ground Power switch on (IG) 4.5 to 14 V

       Tech Tips

       If the result is as specified, there may be a short circuit in the DCM (telematics transceiver).

       Result
       Proceed to OK NG

    
    

    OK

    REPLACE DCM (TELEMATICS TRANSCEIVER) Click here

    NG

18. INSPECT VEHICLE APPROACHING SPEAKER CONTROLLER (SHORT CIRCUIT IN STEREO COMPONENT AMPLIFIER ASSEMBLY)

    
    

    1. Disconnect the K145 vehicle approaching speaker controller connector.

    2. Measure the voltage according to the value(s) in the table below.

       Standard Voltage
       Tester Connection Condition Specified Condition K3-19 (+S) - Body ground Power switch on (IG) 4.5 to 14 V

       Tech Tips

       If the result is as specified, there may be a short circuit in the vehicle approaching speaker controller.

       Result
       Proceed to OK NG

    
    

    OK

    REPLACE VEHICLE APPROACHING SPEAKER CONTROLLER Click here

    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

19. INSPECT VEHICLE APPROACHING SPEAKER CONTROLLER (SHORT CIRCUIT IN STEREO COMPONENT AMPLIFIER ASSEMBLY)

    
    

    1. Connect the K137 certification ECU (smart key ECU assembly) connector.

    2. Measure the voltage according to the value(s) in the table below.

       Standard Voltage
       Tester Connection Condition Specified Condition K3-19 (+S) - Body ground Power switch on (IG) 4.5 to 14 V

       Tech Tips

       If the result is as specified, there may be a short circuit in the vehicle approaching speaker controller.

       Result
       Proceed to OK NG

    
    

    OK

    REPLACE VEHICLE APPROACHING SPEAKER CONTROLLER Click here

    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

20. INSPECT DCM (TELEMATICS TRANSCEIVER) (SHORT CIRCUIT IN STEREO COMPONENT AMPLIFIER ASSEMBLY)

    
    

    1. Connect the K137 certification ECU (smart key ECU assembly) connector.

    2. Measure the voltage according to the value(s) in the table below.

       Standard Voltage
       Tester Connection Condition Specified Condition K3-19 (+S) - Body ground Power switch on (IG) 4.5 to 14 V

       Tech Tips

       If the result is as specified, there may be a short circuit in the DCM (telematics transceiver).

       Result
       Proceed to OK NG

    
    

    OK

    REPLACE DCM (TELEMATICS TRANSCEIVER) Click here

    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)