Toyota Corolla Cross: Speed Signal Circuit

DESCRIPTION

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. In addition, for some systems, vehicle speed information may be received via CAN communication.

W/ SMART KEY SYSTEM

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 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. To create this signal, 12 V is output from terminal SI of the combination meter assembly to the certification ECU (smart key ECU assembly). 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. 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 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. Each ECU connected to terminal +S of the combination meter assembly controls its respective system based on this pulse signal.

W/O SMART KEY SYSTEM

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 terminal SI of 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 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 (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.

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 the combination meter assembly, update the ECU security key.

  Click here

• Before replacing the certification ECU (smart key ECU assembly), refer to Registration.*1

  HEV Model Made: Click here

  Gasoline Model: Click here

  • *1: w/ Smart Key System

PROCEDURE

1.	CHECK COMBINATION METER ASSEMBLY (INPUT VOLTAGE)

(a) Disconnect the I4 combination meter assembly connector.

(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	Switch Condition	Specified Condition
I4-8 (+S) - Body ground	Ignition switch ON	4.5 to 14 V

(c) Connect the I4 combination meter assembly connector.

NG

GO TO STEP 13

OK

2.	CHECK COMBINATION METER ASSEMBLY (INPUT WAVEFORM)

(a) Connect the combination meter assembly connector.

(b) 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 OK: The waveform is similar to that 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.

*a Component with harness connected (Combination Meter Assembly) *b Waveform

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

A

REPLACE COMBINATION METER ASSEMBLY

C

GO TO STEP 9

B

3.	CONFIRM MODEL

(a) Choose the model to be inspected.

Result	Proceed to
w/ Smart Key System	A
w/o Smart Key System	B

B

GO TO STEP 7

A

4.	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 (for Gasoline Model)	A
DTCs are not output (for HEV Model)	B
DTCs are output	C

B

GO TO SMART KEY SYSTEM (FOR START FUNCTION)

C

GO TO SMART KEY SYSTEM (FOR START FUNCTION)

A

5.	CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (SHORT TO GROUND)

(a) Disconnect the I222 certification ECU (smart key ECU assembly) connector.

(b) Measure the voltage according to the value(s) in the table below. Standard Voltage: Tester Connection Switch Condition Specified Condition I222-28 (SPDO) - Body ground Ignition switch off 10 kΩ or higher

*a Component with harness connected (Certification ECU (Smart Key ECU Assembly))

OK

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

NG

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

(a) Disconnect the I4 combination meter assembly connector.

(b) Disconnect the I222 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
I222-28 (SPDO) or I4-25 (SI) - Body ground	Always	10 kΩ or higher

OK

REPLACE COMBINATION METER ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

7.	CHECK SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) (SHORT TO GROUND)

*a	Component with harness connected (Skid Control ECU (Brake Actuator Assembly))

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

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
A151-33 (SP1) - Body ground	Ignition switch off	10 kΩ or higher

OK

REPLACE SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)

NG

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

(a) Disconnect the I4 combination meter assembly connector.

(b) Disconnect the A151 skid control ECU (brake actuator assembly) connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A151-33 (SP1) or I4-25 (SI) - Body ground	Always	10 kΩ or higher

OK

REPLACE COMBINATION METER ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

9.	CONFIRM MODEL

(a) Choose the model to be inspected.

Result	Proceed to
w/ Smart Key System	A
w/o Smart Key System	B

B

GO TO STEP 12

A

10.	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 (for Gasoline Model)	A
DTCs are not output (for HEV Model)	B
DTCs are output	C

B

GO TO SMART KEY SYSTEM (FOR START FUNCTION)

C

GO TO SMART KEY SYSTEM (FOR START FUNCTION)

A

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

(a) Disconnect the I222 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
I222-28 (SPDO) - I4-25 (SI)	Always	Below 1 Ω

OK

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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

(a) Disconnect the A151 skid control ECU (brake actuator 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
A151-33 (SP1) - I4-25 (SI)	Always	Below 1 Ω

OK

REPLACE SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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

(a) Disconnect the A47 ECM connector.*1

• *1: for Gasoline Model

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

(c) Disconnect the I234 stereo component amplifier assembly connector.*1

• *1: w/ Stereo Component Amplifier

(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
A47-42 (SPD) - I4-8 (+S)*1	Always	Below 1 Ω
I55-8 (SPD) - I4-8 (+S)	Always	Below 1 Ω
I234-11 (SPD) - I4-8 (+S)*2	Always	Below 1 Ω
A47-42 (SPD)*1, I55-8 (SPD), I234-11 (SPD)*2 or I4-8 (+S) - Body ground	Always	10 kΩ or higher

• *1: for Gasoline Model
• *2: w/ Stereo Component Amplifier

OK

REPLACE DEFECTIVE ECU

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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