| Last Modified: 08-21-2023 | 6.11:8.1.0 | Doc ID: RM100000001AJJR |
| Model Year Start: 2019 | Model: Avalon HV | Prod Date Range: [04/2018 - 08/2020] |
| Title: METER / GAUGE / DISPLAY: METER / GAUGE SYSTEM (for HV Model): Speed Signal Circuit; 2019 - 2020 MY Avalon HV [04/2018 - 08/2020] | ||
|
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 (brake booster with master cylinder assembly) which uses this information to create the vehicle speed signal*. The vehicle speed signal consists of pulses sent to the combination meter assembly from the skid control ECU (brake booster with master cylinder assembly). 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 (brake booster with master cylinder assembly). The pulse signal is created by switching the transistor in the skid control ECU (brake booster with master cylinder assembly) 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 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 (brake booster with master cylinder assembly). 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 this pulse signal.
- *: This vehicle speed signal is created by the skid control ECU (brake booster with master cylinder assembly). There is no actual component that is referred to as the vehicle speed sensor. In addition, for some systems, vehicle speed information may be received via 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
CAUTION / NOTICE / HINT
NOTICE:
- When replacing the combination meter assembly, always replace it with a new one. If a combination meter assembly which was installed to another vehicle is used, the information stored in it will not match the information from the vehicle and a DTC may be stored.
-
Before replacing the certification ECU (smart key ECU assembly), refer to Registration.
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![2019 - 2020 MY Avalon HV [04/2018 - 08/2020]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, HV Model): REGISTRATION](/t3Portal/stylegraphics/info.gif)
PROCEDURE
|
1. |
INSPECT COMBINATION METER ASSEMBLY (INPUT WAVEFORM) |
|
*a |
Component with harness connected (Combination Meter Assembly) |
|
*b |
Waveform |
(a) Check the signal waveform according to the condition(s) in the table below.
|
Item |
Condition |
|---|---|
|
Tester connection |
G16-5 (SI) - Body ground |
|
Tool setting |
5 V/DIV., 20 ms./DIV. |
|
Condition |
Power switch on (IG), wheel being rotated |
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 |
|---|---|
|
The measured waveform is similar to that in the illustration |
A |
|
The measured waveform is not similar to that in the illustration (Stuck low) |
B |
|
The measured waveform is not similar to that in the illustration (Stuck high) |
C |
| B |
|
| C |
|
|
|
2. |
INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM) |
|
*a |
Component with harness connected (Combination Meter Assembly) |
|
*b |
Waveform |
(a) Check the signal waveform according to the condition(s) in the table below.
|
Item |
Condition |
|---|---|
|
Tester connection |
G16-6 (+S) - Body ground |
|
Tool setting |
5 V/DIV., 20 ms./DIV. |
|
Condition |
Power switch on (IG), wheel being rotated |
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.
- The waveform (B) changes depending on the connected ECUs.
Result |
Proceed to |
|---|---|
|
The measured waveform is similar to that in the illustration |
A |
|
The measured waveform is not similar to that in the illustration (Stuck low) |
B |
|
The measured waveform is not similar to that in the illustration (Stuck high) |
C |
| B |
|
| C |
|
|
|
3. |
CHECK HARNESS AND CONNECTOR (EACH ECU - COMBINATION METER ASSEMBLY) |
(a) Disconnect the G38 vehicle approaching speaker controller connector.
(b) Disconnect the A39 parking brake ECU (brake actuator assembly) connector.
(c) Disconnect the G40 certification ECU (smart key ECU assembly) connector.
(d) Disconnect the G9 DCM (telematics transceiver) connector.
(e) Disconnect the G3 radio and display receiver assembly connector.
(f) Disconnect the G8 stereo component amplifier assembly*1 connector.
(g) Disconnect the G13 navigation ECU*2 connector.
(h) Disconnect the G16 combination meter assembly connector.
(i) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
G38-6 (SPD) - G16-6 (+S) |
Always |
Below 1 Ω |
|
A39-27 (SPD) - G16-6 (+S) |
Always |
Below 1 Ω |
|
G40-19 (SPD) - G16-6 (+S) |
Always |
Below 1 Ω |
|
G9-10 (SPDP) - G16-6 (+S) |
Always |
Below 1 Ω |
|
G3-27 (SPD) - G16-6 (+S) |
Always |
Below 1 Ω |
|
G8-11 (SPD) - G16-6 (+S)*1 |
Always |
Below 1 Ω |
|
G13-9 (SPD) - G16-6 (+S)*2 |
Always |
Below 1 Ω |
- *1: for 14 Speakers
- *2: w/ Navigation System
| OK |
|
CHECK THE VOLTAGE AT TERMINAL SPD OR SPDP OF EACH ECU |
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
4. |
INSPECT EACH ECU (INTERNAL SHORT) |
|
*a |
Component with harness connected (Combination Meter Assembly) |
(a) Disconnect one of the connectors below.
NOTICE:
After disconnecting a connector, perform all steps with all other ECUs connected.
|
Terminal No. (Symbol) |
ECU |
|---|---|
|
G38 |
Vehicle approaching speaker controller |
|
A39 |
Parking brake ECU (brake actuator assembly) |
|
G40 |
Certification ECU (smart key ECU assembly) |
|
G9 |
DCM (telematics transceiver) |
|
G3 |
Radio and display receiver assembly |
|
G8*1 |
Stereo component amplifier assembly |
|
G13*2 |
Navigation ECU |
- *1: for 14 Speakers
- *2: w/ Navigation System
(b) Measure the voltage according to the value(s) in the table below.
NOTICE:
Make sure to perform this inspection with the wheels stopped.
Standard Voltage:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
G16-6 (+S) - Body ground |
Power switch on (IG) |
4.5 to 14 V |
(c) Repeat steps (a) and (b) for each connected ECU.
HINT:
If the voltage changed to the specified voltage after disconnecting a connector, an internal short in the disconnected ECU is suspected.
Result |
Proceed to |
|---|---|
|
After performing the inspection procedure for all connectors, the voltage did not change to the specified voltage |
A |
|
When disconnecting the connector of the vehicle approaching speaker controller, the voltage changed to the specified voltage |
B |
|
When disconnecting the connector of the parking brake ECU (brake actuator assembly), the voltage changed to the specified voltage |
C |
|
When disconnecting the connector of the certification ECU (smart key ECU assembly), the voltage changed to the specified voltage |
D |
|
When disconnecting the connector of the DCM (telematics transceiver), the voltage changed to the specified voltage |
E |
|
When disconnecting the connector of the radio and display receiver assembly, the voltage changed to the specified voltage |
F |
|
When disconnecting the connector of the stereo component amplifier assembly, the voltage changed to the specified voltage (for 14 Speakers) |
G |
|
When disconnecting the connector of the navigation ECU, the voltage changed to the specified voltage (w/ Navigation System) |
H |
| B |
|
| C |
|
| D |
|
| E |
|
| F |
|
| G |
|
| H |
|
|
|
5. |
CHECK HARNESS AND CONNECTOR (EACH ECU - COMBINATION METER ASSEMBLY) |
(a) Disconnect the G38 vehicle approaching speaker controller connector.
(b) Disconnect the A39 parking brake ECU (brake actuator assembly) connector.
(c) Disconnect the G40 certification ECU (smart key ECU assembly) connector.
(d) Disconnect the G9 DCM (telematics transceiver) connector.
(e) Disconnect the G3 radio and display receiver assembly connector.
(f) Disconnect the G8 stereo component amplifier assembly*1 connector.
(g) Disconnect the G13 navigation ECU*2 connector.
(h) Disconnect the G16 combination meter assembly connector.
(i) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
G38-6 (SPD), A39-27 (SPD), G40-19 (SPD), G9-10 (SPDP), G3-27 (SPD), G8-11 (SPD)*1 or G13-9 (SPD)*2 - G16-6 (+S) |
Always |
Below 1 Ω |
|
G38-6 (SPD), A39-27 (SPD), G40-19 (SPD), G9-10 (SPDP), G3-27 (SPD), G8-11 (SPD)*1, G13-9 (SPD)*2 or G16-6 (+S) - Body ground |
Always |
10 kΩ or higher |
- *1: for 14 Speakers
- *2: w/ Navigation System
| OK |
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
6. |
INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE) |
|
*a |
Front view of wire harness connector (to Skid Control ECU (Brake Booster with Master Cylinder Assembly)) |
(a) Disconnect the A35 skid control ECU (brake booster with master cylinder assembly) connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
A35-11 (SP1) - Body ground |
Power switch on (IG) |
11 to 14 V |
| OK |
|
REPLACE SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) |
|
|
7. |
CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - COMBINATION METER ASSEMBLY) |
(a) Disconnect the G16 combination meter assembly connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
A35-11 (SP1) or G16-5 (SI) - Body ground |
Always |
10 kΩ or higher |
| OK |
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
8. |
CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - COMBINATION METER ASSEMBLY) |
(a) Disconnect the A35 skid control ECU (brake booster with master cylinder assembly) connector.
(b) Disconnect the G16 combination meter assembly connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
A35-11 (SP1) - G16-5 (SI) |
Always |
Below 1 Ω |
| OK |
|
REPLACE SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) |
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|