Speed Signal Circuit
METER / GAUGE / DISPLAY: METER / GAUGE SYSTEM: Speed Signal Circuit
- 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 which uses this information to create the vehicle speed sensor signal*1. The vehicle speed sensor signal consists of pulses sent to the combination meter assembly from the skid control ECU. 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. The pulse signal is created by switching the transistor in the skid control ECU 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. 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 the pulse signal.
* *1: This vehicle speed sensor signal is created by the skid control ECU. There is no actual component that is referred to as the vehicle speed sensor. In addition, for some other systems, vehicle speed information may be exchanged using CAN communication.
HINT
This circuit is used for the systems connected to terminal +S. This signal is not used for combination meter assembly operation. Combination meter assembly components such as the speedometer operate using data received via CAN communication.
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:
Text in Illustration
Text in Illustration:
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 -- CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - E31 JUNCTION CONNECTOR)
OK -- Continue to next step.
2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE)
(a) Reconnect the E1 connector.
(b) Disconnect the A42 connector.
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Text in Illustration
Text in Illustration:
NG -- CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - SKID CONTROL ECU)
OK -- Continue to next step.
3. INSPECT SKID CONTROL ECU (INPUT WAVEFORM)
(a) Check the input waveform.
(1) Reconnect the A42 connector.
(2) Remove the combination meter assembly with the connector(s) still connected.
(3) Connect an oscilloscope to terminal E1-8 (SI) and body ground.
(4) Turn the ignition switch ON.
(5) Turn the wheel slowly.
(6) Check the signal waveform according to the condition(s) in the table below.
Text in Illustration
Text in Illustration:
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 ASSEMBLY Removal
4. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - SKID CONTROL ECU)
(a) Disconnect the E1 and A42 connectors.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
Text in Illustration:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE COMBINATION METER ASSEMBLY Removal
5. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - E31 JUNCTION CONNECTOR)
(a) Disconnect the E31 junction connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
Text in Illustration:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
6. CHECK D57, E31 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, 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 D57 junction connector.
(2) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Text in Illustration
Text in Illustration:
Result:
B -- REPLACE A43 JUNCTION CONNECTOR
A -- Continue to next step.
7. CHECK HARNESS AND CONNECTOR (D57 JUNCTION CONNECTOR - D55 JUNCTION CONNECTOR)
(a) Disconnect the D55 junction connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
Text in Illustration:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
8. CHECK A43 JUNCTION CONNECTOR
(a) Inspect for a short in the circuit that is connected to A43 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 A43 junction connector.
(2) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Text in Illustration
Text in Illustration:
Result:
B -- REPLACE JUNCTION CONNECTOR
A -- Continue to next step.
9. SYSTEM CHECK
(a) Select the circuit in which voltage is not present in step 6.
Result:
* *1: w/ Smart Key System
* *2: for Separate Type Amplifier System
* *3: w/ Navigation System
* *4: w/ Automatic Type Headlight Beam Level Control
E -- SYSTEM CHECK
D -- CHECK HARNESS AND CONNECTOR (RADIO RECEIVER CIRCUIT, NAVIGATION RECEIVER ASSEMBLY CIRCUIT)
C -- CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER CIRCUIT)
B -- CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU CIRCUIT)
A -- Continue to next step.
10. CHECK HARNESS AND CONNECTOR (TIRE PRESSURE WARNING ECU CIRCUIT)
(a) Disconnect the D31 connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
Text in Illustration:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE TIRE PRESSURE WARNING ECU Removal
11. CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU CIRCUIT)
(a) Disconnect the D43 connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
Text in Illustration:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE POWER MANAGEMENT CONTROL ECU Removal
12. CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER CIRCUIT)
(a) Disconnect the E14 connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration:
Text in Illustration
Text in Illustration:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE STEREO COMPONENT AMPLIFIER Removal
13. CHECK HARNESS AND CONNECTOR (RADIO RECEIVER CIRCUIT, NAVIGATION RECEIVER ASSEMBLY CIRCUIT)
(a) Disconnect the E6*1, E7*2 or E16*3 connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
* *1: for 6 Speakers
* *2: for 13 Speakers
* *3: w/ Navigation System
Text in Illustration
Text in Illustration:
Result:
C -- REPAIR OR REPLACE HARNESS OR CONNECTOR
B -- REPLACE NAVIGATION RECEIVER ASSEMBLY Removal
A -- REPLACE RADIO RECEIVER Removal
14. SYSTEM CHECK
(a) Select the circuit in which is not present voltage in step 8.
Result:
C -- CHECK HARNESS AND CONNECTOR (HEADLIGHT LEVELING ECU ASSEMBLY CIRCUIT)
B -- CHECK HARNESS AND CONNECTOR (TCM CIRCUIT)
A -- Continue to next step.
15. CHECK HARNESS AND CONNECTOR (ECM CIRCUIT)
(a) Disconnect the A41 connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
* *2: for 2GR-FE
* *3: for 1AR-FE
Text in Illustration
Text in Illustration:
Result:
C -- REPAIR OR REPLACE HARNESS OR CONNECTOR
B -- REPLACE ECM (for 1AR-FE) Removal
A -- REPLACE ECM (for 2GR-FE)
16. CHECK HARNESS AND CONNECTOR (TCM CIRCUIT)
(a) Disconnect the B40 connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
Text in Illustration:
Result:
E -- REPAIR OR REPLACE HARNESS OR CONNECTOR
D -- REPLACE TCM (for U760F)
C -- REPLACE TCM (for U760E)
B -- REPLACE TCM (for U660F) Removal
A -- REPLACE TCM (for U660E)
17. CHECK HARNESS AND CONNECTOR (HEADLIGHT LEVELING ECU ASSEMBLY CIRCUIT)
(a) Disconnect the A40 connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
Text in Illustration:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE HEADLIGHT LEVELING ECU ASSEMBLY Removal