Speed Signal Circuit: Procedure

1. Disconnect the G1 combination meter assembly connector.
   Fig 1: G1 Combination Meter Assembly Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   G1-39 (+S) - Body ground	Power switch on (IG)	4.5 to 14 V

   TEXT IN ILLUSTRATION
   
   

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

   HINT: 

   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.

NG → See step   5 

OK: Go to next step 

1. Reconnect the G1 combination meter assembly connector.
2. Disconnect the A41 skid control ECU connector.
   Fig 2: A41 Skid Control ECU Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A41-11 (SP1) - Body ground	Power switch on (IG)	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

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

NG → See step   4 

OK: Go to next step 

1. Check the input waveform.
   Fig 3: G1 Connector & Waveform

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. Reconnect the A41 skid control ECU connector.
   2. Remove the combination meter assembly with the connector(s) still connected.
   3. Connect an oscilloscope to terminal G1-40 (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	Wheel being rotated

      TEXT IN ILLUSTRATION
      
      

      *a	Component with harness connected (Combination Meter Assembly)

      OK

      The waveform is similar to that shown in the illustration.

      HINT: 

      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.

NG → See step   11 

OK → See step   12 

1. Disconnect the G1 combination meter assembly connector.
2. Disconnect the A41 skid control ECU connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A41-11 (SP1) - G1-40 (SI)	Always	Below 1 Ω
   A41-11 (SP1) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   12 

1. Disconnect the 3B junction connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   G1-39 (+S) - 3B-15	Always	Below 1 Ω
   G1-39 (+S) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Inspect for a short in the circuit that is connected to the junction block connector shown in the wiring diagram.

   HINT: 

   If voltage is not present, it is possible that an ECU or circuit has a malfunction. The malfunctioning ECU or circuit will be diagnosed in the following steps.

   1. Disconnect the 3A junction connector.
   2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection	Condition	Specified Condition
      3A-16 - Body ground	Power switch on (IG)	4.5 to 14 V
      3A-37 - Body ground	Power switch on (IG)	4.5 to 14 V
      3A-38 - Body ground	Power switch on (IG)	4.5 to 14 V

      Result

      Result	Proceed to
      Voltage is not present in one circuit.	A
      Voltage is present in all the circuits.	B

B → REPLACE JUNCTION CONNECTOR (INSTRUMENT PANEL WIRE) 

A: Go to next step 

1. Select the circuit for which voltage was not present in step 6.

   Result

   Tester Connection	System that uses the circuit	Proceed to
   3A-16 - Body ground	Audio/Visual system*1, *2	A
   3A-37 - Body ground	Hybrid control system	B
   3A-38 - Body ground	Vehicle proximity notification system	C

   • *1: for Radio Receiver Type
   • *2: for Radio and Display Type

B → See step   9 

C → See step   10 

A: Go to next step 

1. Disconnect the G41 radio receiver assembly*1 or G78 radio and display receiver assembly*2
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   G41-17 (SPD)*1 - Body ground	Always	10 kΩ or higher
   G78-17 (SPD)*2 - Body ground	Always	10 kΩ or higher

   • *1: for Radio Receiver Type
   • *2: for Radio and Display Type

   Result

   Result	Proceed to
   OK (for Radio Receiver Type)	A
   OK (for Radio and Display Type)	B
   NG	C

B → See step   16 

C → REPAIR OR REPLACE HARNESS OR CONNECTOR 

A → See step   14 

1. Disconnect the G57 power management control ECU assembly connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   G57-14 (SPDI) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   13 

1. Disconnect the G66 vehicle approaching speaker controller connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   G66-6 (SPD) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   15