Component Tests and General Diagnostics

METER / GAUGE / DISPLAY: METER / GAUGE SYSTEM: Speed Signal Circuit
- Speed Signal Circuit

DESCRIPTION

The vehicle speed signal consists of pulses sent to the combination meter assembly from the brake actuator assembly (skid control ECU).

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR)

(a) Check for a short in the circuit that is connected to the junction block connector shown in the wiring diagram.

HINT
If the voltage is not as specified, 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 C59 junction connector.

(2) Disconnect the C58 junction connector.





Text in Illustration





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

Standard Voltage:





*1: w/ Tire Pressure Warning System

*2: w/ Smart Key System

Result





B -- CHECK ECU TERMINAL VOLTAGE (INPUT VOLTAGE)
A -- Continue to next step.

2. SYSTEM CHECK

(a) Select the circuit for which the voltage was not as specified in the previous step.

Result





*1: w/ Tire Pressure Warning System

*2: w/ Smart Key System

*3: for Automatic Transaxle

C -- SYSTEM CHECK

B -- CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR - POWER SOURCE CONTROL ECU)
A -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR - TIRE PRESSURE WARNING ECU)

(a) Disconnect the C59 junction connector.

(b) Disconnect the C40 tire pressure warning ECU connector.

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

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE TIRE PRESSURE WARNING ECU Removal

4. CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR - POWER SOURCE CONTROL ECU)

(a) Disconnect the C58 junction connector.

(b) Disconnect the C43 power source control ECU connector.

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

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE POWER SOURCE CONTROL ECU Removal

5. SYSTEM CHECK

(a) Check the vehicle type.

Result





B -- CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR - JUNCTION CONNECTOR)
A -- Continue to next step.

6. CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR - ECM)

(a) Disconnect the C58 junction connector.

(b) Disconnect the A35 ECM connector.

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

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE ECM Removal

7. CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR - JUNCTION CONNECTOR)

(a) Disconnect the C58 junction connector.

(b) Disconnect the A33 junction connector.

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

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

8. CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR)

(a) Check for a short in the circuit that is connected to the junction connector shown in the wiring diagram.

(1) Disconnect the A33 junction connector.

(2) Disconnect the A32 junction connector.





Text in Illustration





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

Standard Voltage:





Result





C -- REPAIR OR REPLACE HARNESS OR CONNECTOR (JUNCTION CONNECTOR IS DEFECTIVE)

B -- CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR - TCM)
A -- Continue to next step.

9. CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR - ECM)

(a) Disconnect the A33 junction connector.

(b) Disconnect the A35 ECM connector.

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

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE ECM Removal

10. CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR - TCM)

(a) Disconnect the A32 junction connector.

(b) Disconnect the B31 TCM connector.

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

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE TCM Removal

11. CHECK ECU TERMINAL VOLTAGE (INPUT VOLTAGE)

(a) Disconnect the C50 meter connector.





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

Standard Voltage:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

12. CHECK COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE)

(a) Disconnect the A36 skid control ECU connector.





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

Standard Voltage:





Text in Illustration





NG -- CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - SKID CONTROL ECU)
OK -- Continue to next step.

13. CHECK COMBINATION METER ASSEMBLY (SPEED SIGNAL)

(a) Check the input waveform.





(1) Reconnect the C50 meter connector.

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

(3) Connect an oscilloscope to terminal C50-31 (SI) and body ground.

(4) Turn the ignition switch to ON.

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

Measurement Condition





OK:

The waveform displayed is 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.

NG -- REPLACE BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU) Removal

OK -- REPLACE COMBINATION METER ASSEMBLY Removal

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

(a) Disconnect the C50 meter connector.

(b) Disconnect the A36 skid control ECU connector.

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

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE COMBINATION METER ASSEMBLY Removal