Toyota Tacoma (2015-2018) Service Manual: 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
PROCEDURE
|
1. |
INSPECT COMBINATION METER ASSEMBLY (INPUT VOLTAGE) |
|
(a) Disconnect the combination meter assembly connector. |
|
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
|
Tester Connection |
Switch Condition |
Specified Condition |
|---|---|---|
|
C9-40 (+S) - Body ground |
Ignition switch ON |
4.5 to 14 V |
|
*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 | .gif) |
GO TO STEP 5 |
|
.gif)
|
2. |
INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE) |
|
(a) Disconnect the S1 brake actuator assembly (skid control ECU)*1 or brake booster with master cylinder assembly (skid control ECU)*2 connector.
|
|
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
|
Tester Connection |
Switch Condition |
Specified Condition |
|---|---|---|
|
A4-11 (SP1) - Body ground |
Ignition switch ON |
11 to 14 V |
|
*A |
for Vacuum Booster Type |
|
*B |
for Hydraulic Booster Type |
|
*a |
Front view of wire harness connector (to Brake Actuator Assembly) |
| NG | |
GO TO STEP 4 |
|
|
3. |
INSPECT BRAKE ACTUATOR ASSEMBLY (INPUT WAVEFORM) |
|
(a) Check the input waveform. (1) Remove the combination meter assembly with the connector(s) still connected. (2) Connect an oscilloscope to terminal C9-39 (SI) and body ground. (3) Turn the ignition switch to ON. (4) Turn the wheel slowly. (5) Check the signal waveform according to the condition(s) in the table below.
OK: The waveform is similar to that shown in the illustration. Text in 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. |
|
|
Result |
Proceed to |
|---|---|
|
OK |
A |
|
NG (for Vacuum Booster Type) |
B |
|
NG (for Hydraulic Booster Type) |
C |
| A | |
REPLACE COMBINATION METER ASSEMBLY |
| B | |
REPLACE BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU) |
| C | |
REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY (SKID CONTROL ECU) |
|
4. |
CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU) or BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY (SKID CONTROL ECU) - COMBINATION METER ASSEMBLY) |
(a) Disconnect the S1 brake actuator assembly (Skid control ECU)*1 or brake booster with master cylinder assembly (Skid control ECU)*2 connector.
- *1: for Vacuum Booster Type
- *2: for Hydraulic Booster Type
(b) Disconnect the C9 combination meter assembly connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
for Vacuum Booster Type|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
S1-14 (SP1) - C9-39 (SI) |
Always |
Below 1 Ω |
|
S1-14 (SP1) or C9-39 (SI) - Body ground |
Always |
10 kΩ or higher |
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
S1-12 (SP1) - C9-39 (SI) |
Always |
Below 1 Ω |
|
S1-12 (SP1) or C9-39 (SI) - Body ground |
Always |
10 kΩ or higher |
| OK | |
REPLACE COMBINATION METER ASSEMBLY |
| NG | |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
5. |
CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - JUNCTION CONNECTOR) |
(a) Disconnect the C9 combination meter assembly connector.
(b) Disconnect the J11 junction connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
C9-40 (+S) - J11-8 |
Always |
Below 1 Ω |
|
C9-40 (+S) or J11-8 - Body ground |
Always |
10 kΩ or higher |
| NG | |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
6. |
CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR) |
(a) Inspect for a short in the circuit that is connected to the instrument panel junction block assembly 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) Remove the junction connector with the connector(s) still connected.
Text in Illustration
|
*a |
Component with harness connected (Junction Connector) |
- |
- |
(2) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
|
Tester Connection |
Switch Condition |
Specified Condition |
|---|---|---|
|
J11-9 - Body ground |
Ignition switch ON |
4.5 to 14 V |
|
J11-10 - Body ground |
Ignition switch ON |
4.5 to 14 V |
|
J11-11 - Body ground |
Ignition switch ON |
4.5 to 14 V |
|
Result |
Proceed to |
|---|---|
|
Voltage is not as specified in one circuit |
A |
|
Voltage is as specified in all circuits |
B |
| B | |
REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY |
|
|
7. |
SYSTEM CHECK |
(a) Select the circuit for which voltage was not as specified in the previous step 6.
Result|
Tester Connection |
System that Uses the Circuit |
Proceed to |
|---|---|---|
|
J11-9 - Body ground |
Navigation system |
A |
|
J11-10 - Body ground |
Smart key system |
B |
|
J11-11 - Body ground |
Other system (voltage inverter) |
C |
|
E20-23 (SPD)*1 or E13-24 (SPD)*2 - Body ground |
2TR-FE Engine control system*1 2GR-FKS Engine control system*2 |
D |
|
N25-17 (SPD)*3 or R31-17 (SPD)*4 - Body ground |
Navigation system*3 Audio and visual system*4 |
E |
- *1: for 2TR-FE
- *2: for 2GR-FKS
- *3: for Navigation Receiver Type
- *4: for Radio and Display Type
| B | |
GO TO STEP 9 |
| C | |
GO TO STEP 10 |
| D | |
GO TO STEP 11 |
| E | |
GO TO STEP 12 |
|
|
8. |
CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR - STEREO COMPONENT AMPLIFIER ASSEMBLY) |
(a) Disconnect the J11 junction connector.
(b) Disconnect the S23 stereo component amplifier assembly connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
J11-9 - S23-11 (SPD) |
Always |
Below 1 Ω |
|
J11-9 or S23-11 (SPD) - Body ground |
Always |
10 kΩ or higher |
| OK | |
REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY |
| NG | |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
9. |
CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR - CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)) |
(a) Disconnect the J11 junction connector.
(b) Disconnect the C29 certification ECU (smart key ECU assembly) connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
J11-10 - C29-5 (SPD) |
Always |
Below 1 Ω |
|
J11-10 or C29-5 (SPD) - Body ground |
Always |
10 kΩ or higher |
| OK | |
REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) |
| NG | |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
10. |
CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR - VOLTAGE INVERTER ASSEMBLY) |
(a) Disconnect the J11 junction connector.
(b) Disconnect the V8 voltage inverter assembly connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
J11-11 - V8-2 (SPD) |
Always |
Below 1 Ω |
|
J11-11 or V8-2 (SPD) - Body ground |
Always |
10 kΩ or higher |
| OK | |
REPLACE VOLTAGE INVERTER ASSEMBLY |
| NG | |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
11. |
CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - ECM) |
(a) Disconnect the C9 combination meter assembly connector.
(b) Disconnect the E20*1 or E13*2 ECM connector.
- *1: for 2TR-FE
- *2: for 2GR-FKS
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
for 2TR-FE|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
C9-40 (+S) - E20-23 (SPD) |
Always |
Below 1 Ω |
|
C9-40 (+S) or E20-23 (SPD) - Body ground |
Always |
10 kΩ or higher |
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
C9-40 (+S) - E13-24 (SPD) |
Always |
Below 1 Ω |
|
C9-40 (+S) or E13-24 (SPD) - Body ground |
Always |
10 kΩ or higher |
| NG | |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
12. |
CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - NAVIGATION RECEIVER ASSEMBLY OR RADIO AND DISPLAY RECEIVER ASSEMBLY) |
(a) for Navigation Receiver Type
(1) Disconnect the C9 combination meter assembly connector.
(2) Disconnect the N25 navigation receiver assembly connector.
(3) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
C9-40 (+S) - N25-17 (SPD) |
Always |
Below 1 Ω |
|
C9-40 (+S) or N25-17 (SPD) - Body ground |
Always |
10 kΩ or higher |
(b) for Radio and Display Type
(1) Disconnect the C9 combination meter assembly connector.
(2) Disconnect the R31 radio and display receiver assembly connector.
(3) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
C9-40 (+S) - R31-17 (SPD) |
Always |
Below 1 Ω |
|
C9-40 (+S) or R31-17 (SPD) - Body ground |
Always |
10 kΩ or higher |
|
Result |
Proceed to |
|---|---|
|
NG |
A |
|
OK (for Navigation Receiver Type) |
B |
|
OK (for Radio and Display Type) |
C |
| A | |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
| B | |
REPLACE NAVIGATION RECEIVER ASSEMBLY |
| C | |
REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY |
Meter Illumination does not Dim at Night
DESCRIPTION
In this circuit, the combination meter assembly auto dimmer signals from the
main body ECU using the CAN communication system (CAN V1 Bus). When the combination
meter assembly an auto ...
Steering Pad Switch
Components
COMPONENTS
ILLUSTRATION
Removal
REMOVAL
PROCEDURE
1. REMOVE STEERING PAD
(See page
)
2. REMOVE STEERING PAD SWITCH ASSEMBLY
(a) Disconnect the 2 connectors.
...
Other materials:
Removal
REMOVAL
PROCEDURE
1. REMOVE REAR SEAT CUSHION ASSEMBLY
(a) Remove the 6 bolts and 2 rear seat cushion assemblies.
2. REMOVE NO. 4 ROOM PARTITION COVER LH
3. REMOVE NO. 4 ROOM PARTITION COVER RH
4. REMOVE NO. 3 ROOM PARTITION COVER
...
ABS Warning Light Remains ON
DESCRIPTION
If any of the following is detected, the ABS warning light remains on.
The skid control ECU (master cylinder solenoid) connectors are disconnected
from the skid control ECU (master cylinder solenoid).
There is a malfunction in the skid control ECU (master cylinder soleno ...
Vehicle Speed Sensor "A" No Signal (P050031)
DESCRIPTION
Vehicles, which are equipped with ABS (Anti-lock Brake System), detect the vehicle
speed using the skid control ECU (brake actuator assembly) and speed sensors. Each
speed sensor monitors the wheel rotation speed and sends a signal to the skid control
ECU. The skid control ECU con ...
