Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual: Terminals Of Ecu

Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual / Vehicle Interior / Theft Deterrent / Keyless Entry / Immobiliser System / Terminals Of Ecu

TERMINALS OF ECU

CHECK ENGINE SWITCH

(a) Measure the voltage and resistance according to the value(s) in the table below.

Terminal No. (Symbol)	Input/Output	Wiring Color	Terminal Description	Condition	Specified Condition	Related Data List Item/DTC
J14-6 (AGND) - Body ground	-	R - Body ground	Transponder key amplifier ground	Always	Below 1 Ω	-
J14-7 (TXCT) - J14-6 (AGND)	Input	L - R	Immobiliser communication input	Engine switch off, brake pedal not depressed, 30 seconds or more after driver door opened and then closed	Below 1 V	-
J14-8 (CODE) - J14-6 (AGND)	Output	G - R	Immobiliser communication output	Engine switch off, brake pedal not depressed, 30 seconds or more after driver door opened and then closed	Below 1 V	-
J14-10 (VC5) - J14-6 (AGND)	Input	R - R	Transponder key amplifier power supply	Engine switch off, brake pedal not depressed, 30 seconds or more after driver door opened and then closed	Below 1 V	-

(b) Check for pulses according to the value(s) in the table below.

Terminal No. (Symbol)	Input/Output	Wiring Color	Terminal Description	Condition	Specified Condition	Related Data List Item/DTC
J14-7 (TXCT) - J14-6 (AGND)	Input	L - R	Signal input from certification ECU (smart key ECU assembly) (Code sent from certification ECU (smart key ECU assembly) to transponder key amplifier built into engine switch, and then transmitted by transponder key amplifier antenna as radio waves)	Engine switch off, electrical key transmitter sub-assembly not in cabin, within 30 seconds of engine switch pressed	Pulse generation (See waveform 1)	BCC Malfunction Abnormal Status Different Encrypt Code Different Serial Number Frame Error Response HINT: If immobiliser key code verification communication is not performed correctly, the malfunction may be indicated by one or more of the Data List items listed above
J14-8 (CODE) - J14-6 (AGND)	Output	G - R	Signal output to certification ECU (smart key ECU assembly) (Radio waves from transponder key amplifier built into engine switch used to detect key information. Key information then sent to certification ECU (smart key ECU assembly))	Engine switch off, engine switch pressed with electrical key transmitter sub-assembly held near engine switch*	Pulse generation (See waveform 2)
J14-10 (VC5) - J14-6 (AGND)	Input	R - R	Transponder key amplifier power supply (Power supplied from certification ECU (smart key ECU assembly) when transponder key amplifier built into engine switch activated)	Engine switch off, electrical key transmitter sub-assembly not in cabin, within 30 seconds of engine switch pressed	Pulse generation (See waveform 3)

Terminal No. (Symbol)

Input/Output

Wiring Color

Terminal Description

Condition

Specified Condition

Related Data List Item/DTC

J14-7 (TXCT) - J14-6 (AGND)

Input

L - R

Signal input from certification ECU (smart key ECU assembly)

(Code sent from certification ECU (smart key ECU assembly) to transponder key amplifier built into engine switch, and then transmitted by transponder key amplifier antenna as radio waves)

Engine switch off, electrical key transmitter sub-assembly not in cabin, within 30 seconds of engine switch pressed

Pulse generation

(See waveform 1)

BCC Malfunction
Abnormal Status
Different Encrypt Code
Different Serial Number
Frame Error
Response
HINT:

If immobiliser key code verification communication is not performed correctly, the malfunction may be indicated by one or more of the Data List items listed above

J14-8 (CODE) - J14-6 (AGND)

Output

G - R

Signal output to certification ECU (smart key ECU assembly)

(Radio waves from transponder key amplifier built into engine switch used to detect key information. Key information then sent to certification ECU (smart key ECU assembly))

Engine switch off, engine switch pressed with electrical key transmitter sub-assembly held near engine switch*

Pulse generation

(See waveform 2)

J14-10 (VC5) - J14-6 (AGND)

Input

R - R

Transponder key amplifier power supply

(Power supplied from certification ECU (smart key ECU assembly) when transponder key amplifier built into engine switch activated)

Engine switch off, electrical key transmitter sub-assembly not in cabin, within 30 seconds of engine switch pressed

Pulse generation

(See waveform 3)

HINT:

*: Remove the transmitter battery before performing this inspection.

NOTICE:

The waveform shown in the illustration is an example for reference only. Noise, chattering, etc. are not shown.

(1) Waveform 1 (Reference)

Measurement Condition

Item	Content
Tester Connection	J14-7 (TXCT) - J14-6 (AGND)
Tool Setting	2 V/DIV., 20 ms./DIV.
Condition	Engine switch off, electrical key transmitter sub-assembly not in cabin, within 30 seconds of engine switch pressed

(2) Waveform 2 (Reference)

*a	Waveform
*b	Waveform (detail)

Measurement Condition

Item	Content
Tester Connection	J14-8 (CODE) - J14-6 (AGND)
Tool Setting	Waveform 1 V/DIV., 20 ms./DIV. Waveform (detail) 2 V/DIV., 100 μs./DIV.
Condition	Engine switch off, engine switch pressed with electrical key transmitter sub-assembly held near engine switch*

HINT:

*: Remove the transmitter battery before performing this inspection.

(3) Waveform 3 (Reference)

Measurement Condition

Item	Content
Tester Connection	J14-10 (VC5) - J14-6 (AGND)
Tool Setting	2 V/DIV., 200 ms./DIV.
Condition	Engine switch off, electrical key transmitter sub-assembly not in cabin, within 30 seconds of engine switch pressed

CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

(a) Disconnect the J41 certification ECU (smart key ECU assembly) connector.

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

Terminal No. (Symbol)	Input/Output	Wiring Color	Terminal Description	Condition	Specified Condition	Related Data List Item/DTC
J41-4 (+B) - J41-18 (E)	Input	V - W-B	+B power supply	Always	11 to 14 V	-
J41-18 (E) - Body ground	-	W-B - Body ground	Ground	Always	Below 1 Ω	-

(d) Measure the voltage and resistance, and check for pulses according to the value(s) in the table below.

Terminal No. (Symbol)	Input/Output	Wiring Color	Terminal Description	Condition	Specified Condition	Related Data List Item/DTC
J41-17 (IG1D) - J41-18 (E)	Output	G - W-B	Ignition power supply	Engine switch off	Below 1 V	-
J41-17 (IG1D) - J41-18 (E)	Output	G - W-B	Ignition power supply	Engine switch on (IG)	11 to 14 V	-
J41-5 (TXCT) - J41-11 (AGND)	Output	L - R	Signal output to transponder key amplifier	Engine switch off, brake pedal not depressed, 30 seconds or more after driver door opened and then closed	Below 1 V	BCC Malfunction Abnormal Status Different Encrypt Code Different Serial Number Frame Error Response
J41-6 (CODE) - J41-11 (AGND)	Input	G - R	Signal input from transponder key amplifier	Engine switch off, brake pedal not depressed, 30 seconds or more after driver door opened and then closed	Below 1 V
J41-7 (VC5) - J41-11 (AGND)	Output	R - R	Transponder key amplifier power supply	Engine switch off, brake pedal not depressed, 30 seconds or more after driver door opened and then closed	Below 1 V
J41-11 (AGND) - Body ground	-	R - Body ground	Transponder key amplifier ground	Always	Below 1 Ω
J41-20 (IND) - J41-18 (E)	Output	L - W-B	Security indicator output	Engine switch off → on (IG)	Pulse generation → Below 2 V	-

(e) Check for pulses according to the value(s) in the table below.

Terminal No. (Symbol)	Input/Output	Wiring Color	Terminal Description	Condition	Specified Condition	Related Data List Item/DTC
J41-5 (TXCT) - J41-11 (AGND)	Output	L - R	Signal output to transponder key amplifier (Code sent from certification ECU (smart key ECU assembly) to transponder key amplifier built into engine switch, and then transmitted by transponder key amplifier antenna as radio waves)	Engine switch off, electrical key transmitter sub-assembly not in cabin, within 30 seconds of engine switch pressed	Pulse generation (See waveform 1)	BCC Malfunction Abnormal Status Different Encrypt Code Different Serial Number Frame Error Response
J41-6 (CODE) - J41-11 (AGND)	Input	G - R	Signal input from transponder key amplifier (Radio waves from transponder key amplifier built into engine switch used to detect key information. Key information then sent to certification ECU (smart key ECU assembly))	Engine switch off, engine switch pressed with electrical key transmitter sub-assembly held near engine switch HINT: Remove the transmitter battery before performing this inspection.	Pulse generation (See waveform 2)
J41-7 (VC5) - J41-11 (AGND)	Output	R - R	Transponder key amplifier power supply (Power supplied from certification ECU (smart key ECU assembly) when transponder key amplifier built into engine switch activated)	Engine switch off, electrical key transmitter sub-assembly not in cabin, within 30 seconds of engine switch pressed	Pulse generation (See waveform 3)

Terminal No. (Symbol)

Input/Output

Wiring Color

Terminal Description

Condition

Specified Condition

Related Data List Item/DTC

J41-5 (TXCT) - J41-11 (AGND)

Output

L - R

Signal output to transponder key amplifier

(Code sent from certification ECU (smart key ECU assembly) to transponder key amplifier built into engine switch, and then transmitted by transponder key amplifier antenna as radio waves)

Engine switch off, electrical key transmitter sub-assembly not in cabin, within 30 seconds of engine switch pressed

Pulse generation

(See waveform 1)

BCC Malfunction
Abnormal Status
Different Encrypt Code
Different Serial Number
Frame Error
Response

J41-6 (CODE) - J41-11 (AGND)

Input

G - R

Signal input from transponder key amplifier

(Radio waves from transponder key amplifier built into engine switch used to detect key information. Key information then sent to certification ECU (smart key ECU assembly))

Engine switch off, engine switch pressed with electrical key transmitter sub-assembly held near engine switch

HINT:

Remove the transmitter battery before performing this inspection.

Pulse generation

(See waveform 2)

J41-7 (VC5) - J41-11 (AGND)

Output

R - R

Transponder key amplifier power supply

(Power supplied from certification ECU (smart key ECU assembly) when transponder key amplifier built into engine switch activated)

Engine switch off, electrical key transmitter sub-assembly not in cabin, within 30 seconds of engine switch pressed

Pulse generation

(See waveform 3)

(f) Using an oscilloscope, check the waveform.

NOTICE:

The waveform shown in the illustration is an example for reference only. Noise, chattering, etc. are not shown.

(1) Waveform 1 (Reference)

Measurement Condition

Item	Content
Tester Connection	J41-5 (TXCT) - J41-11 (AGND)
Tool Setting	2 V/DIV., 20 ms./DIV.
Condition	Engine switch off, electrical key transmitter sub-assembly not in cabin, within 30 seconds of engine switch pressed

(2) Waveform 2 (Reference)

*a	Waveform
*b	Waveform (detail)

Measurement Condition

Item	Content
Tester Connection	J41-6 (CODE) - J41-11 (AGND)
Tool Setting	Waveform 1 V/DIV., 20 ms./DIV. Waveform (detail) 2 V/DIV., 100 μs./DIV.
Condition	Engine switch off, engine switch pressed with electrical key transmitter sub-assembly held near engine switch*

HINT:

*: Remove the transmitter battery before performing this inspection.

(3) Waveform 3 (Reference)

Measurement Condition

Item	Content
Tester Connection	J41-7 (VC5) - J41-11 (AGND)
Tool Setting	2 V/DIV., 200 ms./DIV.
Condition	Engine switch off, electrical key transmitter sub-assembly not in cabin, within 30 seconds of engine switch pressed

CHECK ID CODE BOX (IMMOBILISER CODE ECU)

(a) Disconnect the J36 ID code box (immobiliser code ECU) connector.

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

Terminal No. (Symbol)	Input/Output	Wiring Color	Terminal Description	Condition	Specified Condition	Related Data List Item/DTC
J36-1 (+B) - Body ground	Input	B - Body ground	+B power supply	Always	11 to 14 V	B2789
J36-5 (GND) - Body ground	-	B - Body ground	Ground	Always	Below 1 Ω	B2789

(d) Measure the voltage and check for pulses according to the value(s) in the table below.

Terminal No. (Symbol)	Input/Output	Wiring Color	Terminal Description	Condition	Specified Condition	Related Data List Item/DTC
J36-3 (EFII) - J36-5 (GND)	Input	B - B	EFI communication input (Signal input from ECM to ID code box (immobiliser code ECU))	Engine switch off	11 to 14 V	B279986 B279A12 EFI Code Receive Engine Start Request
J36-4 (EFIO) - J36-5 (GND)	Output	B - B	EFI communication output (Signal output from ID code box (immobiliser code ECU) to ECM)	Engine switch off	11 to 14 V
J36-3 (EFII) - J36-5 (GND)	Input	B - B	EFI communication input (Signal input from ECM to ID code box (immobiliser code ECU))	Within 3 seconds of engine start or within 3 seconds of engine switch turned on (IG) after cable disconnected and reconnected to battery	Pulse generation (See waveform 1)
J36-4 (EFIO) - J36-5 (GND)	Output	B - B	EFI communication output (Signal output from ID code box (immobiliser code ECU) to ECM)	Engine switch turned on (IG) using registered electrical key transmitter sub-assembly	Pulse generation (See waveform 2)

(e) Using an oscilloscope, check the waveform.

NOTICE:

The waveform shown in the illustration is an example for reference only. Noise, chattering, etc. are not shown.

(1) Waveform 1 (Reference)

Approximately 160 ms.

Approximately 270 ms.

Measurement Condition

Item	Content
Tester Connection	J36-3 (EFII) - J36-5 (GND)
Tool Setting	2 V/DIV., 500 ms./DIV.
Condition	Within 3 seconds of engine start or within 3 seconds of engine switch turned on (IG) after cable disconnected and reconnected to battery

(2) Waveform 2 (Reference)

Approximately 160 ms.

Approximately 270 ms.

Measurement Condition

Item	Content
Tester Connection	J36-4 (EFIO) - J36-5 (GND)
Tool Setting	2 V/DIV., 500 ms./DIV.
Condition	Engine switch turned on (IG) using registered electrical key transmitter sub-assembly

CHECK STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY)

(a) Measure the voltage and resistance, and check for pulses according to the value(s) in the table below.

Terminal No. (Symbol)	Input/Output	Wiring Color	Terminal Description	Condition	Specified Condition	Related Data List Item/DTC
L1-1 (GND) - Body ground	-	W-B - Body ground	Ground	Always	Below 1 Ω	-
L1-3 (IGE) - L1-1 (GND)	Input	SB - W-B	Steering lock motor operation permission signal (motor operation permission signal supplied by certification ECU (smart key ECU assembly))	Steering lock motor operating when all conditions met, and then door opened: Shift lever in P Steering unlocked Engine switch turned off	Pulse generation (See waveform 1)	Power Supply Short Unlock Request Receive Lock Request Receive
L1-4 (SLP1) - L1-1 (GND)	Output	GR - W-B	Steering lock bar position signal (signal output from steering unlock sensor)	Steering locked → unlocked*	11 to 14 V → Below 1.5 V	Sensor Value
L1-6 (IG2) - L1-1 (GND)	Input	P - W-B	IG signal (IG2 power supply input for steering lock motor)	Engine switch off	Below 1 V	B2788
L1-6 (IG2) - L1-1 (GND)	Input	P - W-B	IG signal (IG2 power supply input for steering lock motor)	Engine switch on (IG)	11 to 14 V	B2788
L1-7 (B) - Body ground	Input	V - Body ground	Constant power supply	Always	11 to 14 V	B2788

HINT:

*: The steering locks when any door is opened with the shift lever in P and the engine switch off. The steering unlocks when the engine switch is turned on (ACC).

(b) Using an oscilloscope, check the waveform.

NOTICE:

The waveform shown in the illustration is an example for reference only. Noise, chattering, etc. are not shown.

(1) Waveform 1 (Reference)

*a	Steering lock motor not operating
*b	Steering lock motor operating

Measurement Condition

Item	Content
Tester Connection	L1-3 (IGE) - L1-1 (GND)
Tool Setting	2 V/DIV., 200 ms./DIV.
Condition	Steering lock motor operating when all conditions met, and then door opened: Shift lever in P Steering unlocked Engine switch turned off

CHECK ECM

(a) Measure the voltage and resistance, and check for pulses according to the value(s) in the table below.

Terminal No. (Symbol)	Input/Output	Wiring Color	Terminal Description	Condition	Specified Condition	Related Data List Item/DTC
A37-3 (+B2) - D2-53 (E1)	Input	L - BR	Ignition power supply	Engine switch on (IG)	11 to 14 V	-
A37-2 (+B) - D2-53 (E1)	Input	R - BR	Ignition power supply	Engine switch on (IG)	11 to 14 V	-
A37-46 (MREL) - D2-51 (E01)	Input	Y - W-B	Ignition power supply	Engine switch on (IG)	11 to 14 V	-
A37-1 (BATT) - D2-53 (E1)	Input	G - BR	+B power supply	Always	11 to 14 V	-
D2-51 (E01) - Body ground	-	W-B - Body ground	Ground	Always	Below 1 Ω	-
D2-53 (E1) - Body ground	-	BR - Body ground	Ground	Always	Below 1 Ω	-
D2-20 (E02) - Body ground	-	W-B - Body ground	Ground	Always	Below 1 Ω	-
A37-45 (IMO) - D2-53 (E1)	Output	G - BR	ID code box (immobiliser code ECU) communication output	Engine switch off	11 to 14 V	-
A37-45 (IMO) - D2-53 (E1)	Output	G - BR	ID code box (immobiliser code ECU) communication output	Within 3 seconds of engine start or within 3 seconds of engine switch turned on (IG) after cable disconnected and reconnected to battery	Pulse generation (See waveform 1)	-
A37-59 (IMI) - D2-53 (E1)	Input	L - BR	ID code box (immobiliser code ECU) communication input	Engine switch off	11 to 14 V	-
A37-59 (IMI) - D2-53 (E1)	Input	L - BR	ID code box (immobiliser code ECU) communication input	Engine switch turned on (IG) using registered electrical key transmitter sub-assembly	Pulse generation (See waveform 2)	-

(b) Using an oscilloscope, check the waveform.

NOTICE:

The waveform shown in the illustration is an example for reference only. Noise, chattering, etc. are not shown.

(1) Waveform 1 (Reference)

Approximately 160 ms.

Approximately 270 ms.

Measurement Condition

Item	Content
Tester Connection	A37-45 (IMO) - D2-53 (E1)
Tool Setting	2 V/DIV., 500 ms./DIV.
Condition	Within 3 seconds of engine start or within 3 seconds of engine switch turned on (IG) after cable disconnected and reconnected to battery

(2) Waveform 2 (Reference)

Approximately 160 ms.

Approximately 270 ms.

Measurement Condition

Item	Content
Tester Connection	A37-59 (IMI) - D2-53 (E1)
Tool Setting	2 V/DIV., 500 ms./DIV.
Condition	Engine switch turned on (IG) using registered electrical key transmitter sub-assembly

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