Last Modified: 08-21-2023 6.11:8.1.0 Doc ID: RM100000001Q41C
Model Year Start: 2021 Model: Avalon Prod Date Range: [08/2020 -           ]
Title: METER / GAUGE / DISPLAY: METER / GAUGE SYSTEM (for Gasoline Model): Speed Signal Circuit; 2021 - 2022 MY Avalon [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 actuator 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 actuator 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 actuator assembly). The pulse signal is created by switching the transistor in the skid control ECU (brake actuator 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 actuator 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 actuator 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.

    Click here 2021 - 2022 MY Avalon [08/2020 -        ]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): REGISTRATION

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

Engine 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

GO TO STEP 6

C

GO TO STEP 8

A

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

Engine 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

GO TO STEP 4

C

REPLACE COMBINATION METER ASSEMBLY 2021 MY Avalon Avalon HV [08/2020 - 08/2021]; METER / GAUGE / DISPLAY: COMBINATION METER: REMOVAL 2022 MY Avalon Avalon HV [08/2021 -        ]; METER / GAUGE / DISPLAY: COMBINATION METER: REMOVAL

A

3.

CHECK HARNESS AND CONNECTOR (EACH ECU - COMBINATION METER ASSEMBLY)

(a) Disconnect the A18*1 or A64*2 ECM connector.

(b) Disconnect the G40 certification ECU (smart key ECU assembly) connector.

(c) Disconnect the G3 radio and display receiver assembly connector.

(d) Disconnect the G8 stereo component amplifier assembly*3 connector.

(e) Disconnect the G13 navigation ECU*4 connector.

(f) Disconnect the G16 combination meter assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A18-39 (SPD) - G16-6 (+S)*1

Always

Below 1 Ω

A64-42 (SPD) - G16-6 (+S)*2

Always

Below 1 Ω

G40-19 (SPD) - G16-6 (+S)

Always

Below 1 Ω

G3-27 (SPD) - G16-6 (+S)

Always

Below 1 Ω

G8-11 (SPD) - G16-6 (+S)*3

Always

Below 1 Ω

G13-9 (SPD) - G16-6 (+S)*4

Always

Below 1 Ω
  • *1: for 2GR-FKS
  • *2: for A25A-FKS
  • *3: for 14 Speakers
  • *4: 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

A18*1

ECM

A64*2

G40

Certification ECU (smart key ECU assembly)

G3

Radio and display receiver assembly

G8*3

Stereo component amplifier assembly

G13*4

Navigation ECU
  • *1: for 2GR-FKS
  • *2: for A25A-FKS
  • *3: for 14 Speakers
  • *4: 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

Engine 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 ECM, the voltage changed to the specified voltage

B

When disconnecting the connector of the certification ECU (smart key ECU assembly), the voltage changed to the specified voltage

C

When disconnecting the connector of the radio and display receiver assembly, the voltage changed to the specified voltage

D

When disconnecting the connector of the stereo component amplifier assembly, the voltage changed to the specified voltage

(for 14 Speakers)

E

When disconnecting the connector of the navigation ECU, the voltage changed to the specified voltage

(w/ Navigation System)

F
B

REPLACE ECM

for 2GR-FKS: Click here 2019 - 2021 MY Avalon [04/2018 - 08/2021]; 2GR-FKS (ENGINE CONTROL): ECM: REMOVAL 2022 MY Avalon [08/2021 -        ]; 2GR-FKS (ENGINE CONTROL): ECM: REMOVAL

for A25A-FKS: Click here 2021 - 2022 MY Avalon [08/2020 -        ]; A25A-FKS (ENGINE CONTROL): ECM: REMOVAL

C

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) 2019 - 2021 MY Avalon Avalon HV [04/2018 - 08/2021]; THEFT DETERRENT / KEYLESS ENTRY: CERTIFICATION ECU: REMOVAL 2022 MY Avalon Avalon HV [08/2021 -        ]; THEFT DETERRENT / KEYLESS ENTRY: CERTIFICATION ECU: REMOVAL

D

REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY

E

REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY 2019 - 2021 MY Avalon Avalon HV [04/2018 - 08/2021]; AUDIO / VIDEO: STEREO COMPONENT AMPLIFIER: REMOVAL 2022 MY Avalon Avalon HV [08/2021 -        ]; AUDIO / VIDEO: STEREO COMPONENT AMPLIFIER: REMOVAL

F

REPLACE NAVIGATION ECU

A

5.

CHECK HARNESS AND CONNECTOR (EACH ECU - COMBINATION METER ASSEMBLY)

(a) Disconnect the A18*1 or A64*2 ECM connector.

(b) Disconnect the G40 certification ECU (smart key ECU assembly) connector.

(c) Disconnect the G3 radio and display receiver assembly connector.

(d) Disconnect the G8 stereo component amplifier assembly*3 connector.

(e) Disconnect the G13 navigation ECU*4 connector.

(f) Disconnect the G16 combination meter assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A18-39 (SPD)*1, A64-42 (SPD)*2, G40-19 (SPD), G3-27 (SPD), G8-11 (SPD)*3 or G13-9 (SPD)*4 - G16-6 (+S)

Always

Below 1 Ω

A18-39 (SPD)*1, A64-42 (SPD)*2, G40-19 (SPD), G3-27 (SPD), G8-11 (SPD)*3, G13-9 (SPD)*4 or G16-6 (+S) - Body ground

Always

10 kΩ or higher
  • *1: for 2GR-FKS
  • *2: for A25A-FKS
  • *3: for 14 Speakers
  • *4: w/ Navigation System
OK

REPLACE COMBINATION METER ASSEMBLY 2021 MY Avalon Avalon HV [08/2020 - 08/2021]; METER / GAUGE / DISPLAY: COMBINATION METER: REMOVAL 2022 MY Avalon Avalon HV [08/2021 -        ]; METER / GAUGE / DISPLAY: COMBINATION METER: REMOVAL

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 Actuator Assembly))

(a) Disconnect the A28 skid control ECU (brake actuator assembly) connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A28-34 (SP1) - Body ground

Engine switch on (IG)

11 to 14 V
OK

REPLACE SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) 2021 MY Avalon [08/2020 - 08/2021]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: BRAKE ACTUATOR (for Gasoline Model): REMOVAL 2022 MY Avalon [08/2021 -        ]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: BRAKE ACTUATOR (for Gasoline Model): REMOVAL

NG

7.

CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE ACTUATOR 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

A28-34 (SP1) or G16-5 (SI) - Body ground

Always

10 kΩ or higher
OK

REPLACE COMBINATION METER ASSEMBLY 2021 MY Avalon Avalon HV [08/2020 - 08/2021]; METER / GAUGE / DISPLAY: COMBINATION METER: REMOVAL 2022 MY Avalon Avalon HV [08/2021 -        ]; METER / GAUGE / DISPLAY: COMBINATION METER: REMOVAL

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

8.

CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) - COMBINATION METER ASSEMBLY)

(a) Disconnect the A28 skid control ECU (brake actuator 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

A28-34 (SP1) - G16-5 (SI)

Always

Below 1 Ω
OK

REPLACE SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) 2021 MY Avalon [08/2020 - 08/2021]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: BRAKE ACTUATOR (for Gasoline Model): REMOVAL 2022 MY Avalon [08/2021 -        ]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: BRAKE ACTUATOR (for Gasoline Model): REMOVAL

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR