Speed Signal Circuit

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

DESCRIPTION

The meter CPU receives vehicle speed signals from this circuit. The vehicle speed sensor detects the voltage that varies according to the vehicle speed. The skid control ECU supplies power to the vehicle speed sensor. The skid control ECU detects vehicle speed signals based on the pulses of the voltage. The skid control ECU transmits vehicle speed signals as pulses to the meter CPU. A voltage of 12 V is output from the combination meter assembly and then input to the skid control ECU. The signal is changed to a pulse signal at the transistor in the combination meter assembly.

A voltage of 12 V or 5 V is output from each ECU or relay and then input to the combination meter assembly.

Each ECU controls the respective system based on the pulse signal.

HINT
This circuit is used for another system, and is not used for combination meter operation.

WIRING DIAGRAM

1. for 2GR-FE

2. for 1AR-FE

INSPECTION PROCEDURE

PROCEDURE

1. INSPECT ECU TERMINAL VOLTAGE (INPUT VOLTAGE)

(a) Disconnect the E1 connector.

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

Standard voltage:

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

NG -- CHECK HARNESS AND CONNECTOR (COMBINATION METER - JUNCTION CONNECTOR)
OK -- Continue to next step.

2. INSPECT COMBINATION METER (OUTPUT VOLTAGE)

(a) Reconnect the E1 connector.

(b) Disconnect the A24 connector.

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

3. INSPECT SKID CONTROL ECU (INPUT WAVEFORM)

(a) Check the input waveform.

(1) Reconnect the A24 connector.

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

(3) Connect the oscilloscope to terminals E1-29 (SI) and body ground.

(4) Ignition switch on (IG).

(5) Turn the wheel slowly.

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

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.

NG -- REPLACE SKID CONTROL ECU Removal

OK -- REPLACE COMBINATION METER Removal

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

(a) Disconnect the E1 connector.

(b) 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 Removal

5. CHECK HARNESS AND CONNECTOR (COMBINATION METER - JUNCTION CONNECTOR)

(a) Disconnect the junction connector.

(b) 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.

6. CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR)

(a) 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, the circuit (ECU) was possibly the malfunctioning circuit. This is the circuit that will be diagnosed by following the A step that follows.

(1) Disconnect the junction connectors.

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

Standard voltage:

*1: w/ Smart Key System

*2: w/ Tire Pressure Warning System

*3: w/o Navigation System

*4: w/ Navigation System

*5: w/ Back Door Speaker

Result:

B -- REPLACE JUNCTION CONNECTOR
A -- Continue to next step.

7. SYSTEM CHECK

(a) Select the circuit that did not present the voltage in the step 6.

Result:

*1: w/ Smart Key System

*2: w/o Navigation System

*3: w/ Navigation System

*4: w/ Back Door Speaker

*5: w/ Tire Pressure Warning System

B -- CHECK HARNESS AND CONNECTOR (ECM CIRCUIT, TCM CIRCUIT)

C -- CHECK HARNESS AND CONNECTOR (RADIO RECEIVER CIRCUIT, NAVIGATION RECEIVER CIRCUIT)

D -- CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY CIRCUIT)

E -- CHECK HARNESS AND CONNECTOR (TIRE PRESSURE WARNING ECU CIRCUIT)
A -- Continue to next step.

8. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU CIRCUIT)

(a) Disconnect the D9 (*1) connector.

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

Standard resistance:

*1: w/ Smart Key System

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE MAIN BODY ECU

9. CHECK HARNESS AND CONNECTOR (ECM CIRCUIT, TCM CIRCUIT)

(a) Disconnect the B52 (*1), D61 (*2), or D60 (*3) connector.

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

Standard resistance:

*1: for U760E Automatic Transaxle System

*2: for 2GR-FE

*3: for 1AR-FE

Result:

B -- REPLACE ECM (for 1AR-FE) Removal

C -- REPLACE TCM (for U760E)

D -- REPAIR OR REPLACE HARNESS OR CONNECTOR

A -- REPLACE ECM (for 2GR-FE) Removal

10. CHECK HARNESS AND CONNECTOR (RADIO RECEIVER CIRCUIT, NAVIGATION RECEIVER CIRCUIT)

(a) Disconnect the E3 (*1) or E5 (*2) connector.

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

Standard resistance:

*1: w/o Navigation System

*2: w/ Navigation System

Result:

B -- REPLACE NAVIGATION RECEIVER Removal

C -- REPAIR OR REPLACE HARNESS OR CONNECTOR

A -- REPLACE RADIO RECEIVER Removal

11. CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY CIRCUIT)

(a) Disconnect the N14 (*1) connector.

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

Standard resistance:

*1: w/ Back Door Speaker

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY Removal

12. CHECK HARNESS AND CONNECTOR (TIRE PRESSURE WARNING ECU CIRCUIT)

(a) Disconnect the D33 (*1) connector.

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

Standard resistance:

*1: w/ Tire Pressure Warning System

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE TIRE PRESSURE WARNING ECU Removal