Speed Signal Circuit: Procedure

1. Disconnect the combination meter assembly connector.
   Fig 1: Measuring Voltage Of 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	Switch Condition	Specified Condition
   C1-16 (+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.

3. Reconnect the combination meter assembly connector.

NG → See step   5 

OK: Go to next step 

1. Reconnect the C1 combination meter assembly connector.
   Fig 2: Measuring Voltage Of Master Cylinder Assembly (Skid Control ECU) Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Disconnect the brake booster with master cylinder assembly (skid control ECU) connector.
3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   A20-11 (SP1) - Body ground	Power switch on (IG)	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to Brake Booster with Master Cylinder Assembly - Skid Control ECU)

4. Reconnect the brake booster with master cylinder assembly (skid control ECU) connector.

NG → See step   4 

OK: Go to next step 

1. Check the input waveform.
   Fig 3: Identifying Combination Meter Assembly Connector Terminals With Waveform

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. Remove the combination meter assembly with the connector(s) still connected.
   2. Connect an oscilloscope to terminal C1-17 (SI) and body ground.
   3. Turn the power switch on (IG).
   4. Turn the wheel slowly.
   5. 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	Driving at approx. 20 km/h (12 mph)

      OK

      The waveform is displayed as 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.

      TEXT IN ILLUSTRATION
      
      

      *a	Component with harness connected (Combination Meter Assembly)

NG → See step   14 

OK → See step   15 

1. Disconnect the C1 combination meter assembly and A20 brake booster with master cylinder assembly (skid control ECU) connectors.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A20-11 (SP1) - C1-17 (SI)	Always	Below 1 Ω
   A20-11 (SP1) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   16 

1. Disconnect the C46 junction connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   C1-16 (+S) - C46-71	Always	Below 1 Ω
   C1-16 (+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 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 C46 junction connector.
   2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection	Condition	Specified Condition	Connected to
      C46-61 - Body ground	Power switch on (IG)	4.5 to 14 V	Junction connector
      C46-91 - Body ground	Power switch on (IG)	4.5 to 14 V	Power management control ECU
      C46-92 - Body ground	Power switch on (IG)	4.5 to 14 V	Tire pressure warning ECU

      RESULT
      
      

      Result	Proceed to
      OK	A
      NG (Between junction connector to junction connector)	B
      NG (Between junction connector to power management control ECU)	C
      NG (Between junction connector to tire pressure warning ECU)	D

B → See step   7 

C → See step   9 

D → See step   10 

A → REPLACE JUNCTION CONNECTOR (INSTRUMENT PANEL WIRE) 

1. Disconnect the C49 connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   C46-61 - C49-14	Always	Below 1 Ω
   C46-61 - 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 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. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection	Condition	Specified Condition	Connected to
      C49-12 - Body ground	Power switch on (IG)	4.5 to 14 V	Vehicle approaching speaker controller
      C49-13 - Body ground	Power switch on (IG)	4.5 to 14 V	Radio and display receiver assembly
      C49-15 - Body ground	Power switch on (IG)	4.5 to 14 V	DCM (telematics transceiver)

      RESULT
      
      

      Result	Proceed to
      OK	A
      NG (Between junction connector to vehicle approaching speaker controller)	B
      NG (Between junction connector to radio and display receiver assembly)	C
      NG (Between junction connector to DCM (telematics transceiver)	D

B → See step   11 

C → See step   12 

D → See step   13 

A → REPLACE JUNCTION CONNECTOR (INSTRUMENT PANEL WIRE) 

1. Disconnect the C22 connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   C22-22 (SPDI) - C46-91	Always	Below 1 Ω
   C22-22 (SPDI) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   17 

1. Disconnect the C67 connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   C67-2 (SPD) - C46-92	Always	Below 1 Ω
   C67-2 (SPD) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   18 

1. Disconnect the C64 connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   C64-6 (SPD) - C49-12	Always	Below 1 Ω
   C64-6 (SPD) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   19 

1. Disconnect the C43 connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   C43-17 (SPD) - C49-13	Always	Below 1 Ω
   C43-17 (SPD) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   20 

1. Disconnect the C70 connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   C70-10 (SPDP) - C49-15	Always	Below 1 Ω
   C70-10 (SPDP) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   21