Last Modified: 07-31-2024 6.11:8.1.0 Doc ID: RM1000000028VAH
Model Year Start: 2023 Model: GR Corolla Prod Date Range: [11/2022 -           ]
Title: METER / GAUGE / DISPLAY: METER / GAUGE SYSTEM (for 12.3 Inch Display): Speed Signal Circuit; 2023 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [11/2022 -        ]

Speed Signal Circuit

DESCRIPTION

SPEED SIGNAL CIRCUIT CONTROL

(a) The wheel speed sensors produce an output that varies according to the vehicle speed.

(b) 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.

(c) The vehicle speed signal is output from the skid control ECU (brake actuator assembly) to the certification ECU (smart key ECU assembly) and then to the combination meter assembly.

(d) To create this signal, 12 V is output from terminal SI of the combination meter assembly to the certification ECU (smart key ECU assembly).

(e) The pulse signal is created by switching the transistor in the certification ECU (smart key ECU assembly) on and off, making the voltage on the wire drop to 0 V.

(f) A similar system is used for the output of this signal from the combination meter assembly via terminal +S.

(g) A voltage of 12 V or 5 V is applied to terminal +S from each ECU or relay that is connected to this terminal.

(h) The transistor in the combination meter assembly is controlled by the signal from the certification ECU (smart key ECU 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.

(i) Each ECU connected to terminal +S of the combination meter assembly controls its respective system based on this pulse signal.

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.
  • When replacing any of the following ECUs, update the ECU security key.

    Click here 2023 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [09/2022 -        ]; SETUP: WHEN REPLACING OR REMOVING/INSTALLING PARTS: UPDATE ECU SECURITY KEY

    • Combination meter assembly
    • ECM
    • Certification ECU (smart key ECU assembly)
  • When the electronically controlled brake system is malfunctioning, a correct vehicle speed signal may not be received. Before preforming this procedure, confirm that the electronically controlled brake system is not malfunctioning.

    Click here 2023 - 2025 MY Corolla Corolla Hatchback GR Corolla [11/2022 -        ]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for Gasoline Model without Electric Parking Brake System TMC Made): HOW TO PROCEED WITH TROUBLESHOOTING

  • Before replacing any of the following ECUs, refer to Registration.

    Click here 2023 - 2025 MY Corolla Corolla Hatchback GR Corolla [11/2022 -        ]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): REGISTRATION

    • ECM
    • Certification ECU (smart key ECU assembly)

PROCEDURE

1.

INSPECT COMBINATION METER ASSEMBLY (INPUT WAVEFORM)

*a

Component with harness connected

(Combination Meter Assembly)

*b

Input Waveform

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

Item

Condition

Tester connection

I4-25 (SI) - Body ground

Tool setting

5 V/DIV., 20 ms./DIV.

Condition

Ignition switch ON, wheel being rotated

NOTICE:

Perform the inspection from the back of the connector with the connector connected.

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 9

A

2.

INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)

*a

Component with harness connected

(Combination Meter Assembly)

*b

Output Waveform

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

Item

Condition

Tester connection

I4-8 (+S) - Body ground

Tool setting

5 V/DIV., 20 ms./DIV.

Condition

Ignition switch ON, wheel being rotated

NOTICE:

Perform the inspection from the back of the connector with the connector connected.

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

A

3.

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

(a) Disconnect the A139 ECM connector.

(b) Disconnect the I55 radio and display receiver assembly connector.

(c) Disconnect the I68 stereo component amplifier assembly* connector.

(d) Disconnect the I4 combination meter assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A139-42 (SPD) - I4-8 (+S)

Always

Below 1 Ω

I55-8 (SPD) - I4-8 (+S)

Always

Below 1 Ω

I68-11 (SPD) - I4-8 (+S)*

Always

Below 1 Ω
  • *: for JBL Model
OK

CHECK THE VOLTAGE AT TERMINAL SPD OF EACH ECU
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.

INSPECT EACH ECU (INTERNAL SHORT)

(a) Disconnect one of the connectors below.

NOTICE:

After disconnecting a connector, perform all steps with all other devices connected.

Connector

ECU

A139

ECM

I55

Radio and display receiver assembly

I68*

Stereo component amplifier assembly
  • *: for JBL Model

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

NOTICE:

  • Make sure to perform this inspection with the wheels stopped.
  • Perform the inspection from the back of the connector with the connector connected.

Standard Voltage:

Tester Connection

Condition

Specified Condition

I4-8 (+S) - Body ground

Ignition switch ON

4.5 to 14 V

*a

Component with harness connected

(Combination Meter Assembly)

(c) Repeat steps (a) and (b) for each connected ECU.

HINT:

If the waveform changes to the waveform shown in the illustration 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 radio and display receiver assembly, the voltage changed to the specified voltage

C

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

(for JBL Model)

D
B

REPLACE ECM

C

REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY

D

REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY

A

5.

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

(a) Disconnect the A139 ECM connector.

(b) Disconnect the I55 radio and display receiver assembly connector.

(c) Disconnect the I68 stereo component amplifier assembly* connector.

(d) Disconnect the I4 combination meter assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A139-42 (SPD), I55-8 (SPD), I68-11 (SPD)* - I4-8 (+S)

Always

Below 1 Ω

A139-42 (SPD), I55-8 (SPD), I68-11 (SPD)* or I4-8 (+S) - Body ground

Always

10 kΩ or higher
  • *: for JBL Model
OK

REPLACE COMBINATION METER ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

6.

CHECK FOR DTC (SMART KEY SYSTEM (FOR START FUNCTION))

(a) Check if smart key system (for start function) DTCs are output.

Body Electrical > Power Source Control > Trouble Codes

Result

Proceed to

DTCs are not output

A

DTCs are output

B
B

GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START (FOR START FUNCTION) 2023 MY Corolla Corolla Hatchback GR Corolla [11/2022 - 03/2023]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): DIAGNOSTIC TROUBLE CODE CHART 2023 - 2025 MY Corolla Corolla Hatchback GR Corolla [03/2023 -        ]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): DIAGNOSTIC TROUBLE CODE CHART

A

7.

INSPECT COMBINATION METER ASSEMBLY

HINT:

This procedure is performed to check the diode inside the combination meter assembly.

(a) Remove the combination meter assembly.

Click here 2023 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [11/2022 -        ]; METER / GAUGE / DISPLAY: COMBINATION METER: REMOVAL

(b) Measure the internal resistance of the combination meter assembly.

Standard Resistance:

Tester Connection

Tester Connection

Condition

Measured Value

I4-6 (IG+) - I4-25 (SI)
  • Positive (+) tester probe → I4-6 (IG+)
  • Negative (-) tester probe → I4-25 (SI)

Always

A

I4-6 (IG+) - I4-25 (SI)
  • Positive (+) tester probe → I4-25 (SI)
  • Negative (-) tester probe → I4-6 (IG+)

Always

B

OK:

There is a large difference between the measured value (A) and the measured value (B).

NG

REPLACE COMBINATION METER ASSEMBLY

OK

8.

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - COMBINATION METER ASSEMBLY)

(a) Disconnect the I167 certification ECU (smart key ECU assembly) connector.

(b) Disconnect the I4 combination meter assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I167-28 (SPDO) or I4-25 (SI) - Body ground

Always

10 kΩ or higher
OK

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

9.

CHECK FOR DTC (SMART KEY SYSTEM (FOR START FUNCTION))

(a) Check if smart key system (for start function) DTCs are output.

Body Electrical > Power Source Control > Trouble Codes

Result

Proceed to

DTCs are not output

A

DTCs are output

B
B

GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START (FOR START FUNCTION) 2023 MY Corolla Corolla Hatchback GR Corolla [11/2022 - 03/2023]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): DIAGNOSTIC TROUBLE CODE CHART 2023 - 2025 MY Corolla Corolla Hatchback GR Corolla [03/2023 -        ]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): DIAGNOSTIC TROUBLE CODE CHART

A

10.

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - COMBINATION METER ASSEMBLY)

(a) Disconnect the I167 certification ECU (smart key ECU assembly) connector.

(b) Disconnect the I4 combination meter assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I167-28 (SPDO) - I4-25 (SI)

Always

Below 1 Ω
OK

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR