Lexus ES: Lost Communication with Blind Spot Monitor Slave Module (U0232,U0233)

Lexus ES (XZ10) Service Manual / Audio & Visual & Telematics / Park Assist / Monitoring / Parking Support Brake System (for Gasoline Model) / Lost Communication with Blind Spot Monitor Slave Module (U0232,U0233)

DESCRIPTION

This DTC is stored when the blind spot monitor sensor LH judges that there is a communication problem with the blind spot monitor sensor RH.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area
U0232	Lost Communication with Blind Spot Monitor Slave Module	The clearance warning ECU assembly cannot receive signals from the blind spot monitor sensor (slave)	Open or short in CAN bus main wire or connector Open or short in CAN bus wire or connector Open or short in No. 24 junction connector Clearance warning ECU assembly Blind spot monitor sensor LH Power source circuit of blind spot monitor sensor LH Blind spot monitor sensor LH ground circuit Blind spot monitor sensor RH
U0233	Lost Communication with Blind Spot Monitor Master Module	The clearance warning ECU assembly cannot receive signals from the blind spot monitor sensor (master)	Open or short in CAN bus main wire or connector Open or short in CAN bus wire or connector Open or short in No. 24 junction connector Clearance warning ECU assembly Blind spot monitor sensor RH Power source circuit of blind spot monitor sensor RH Blind spot monitor sensor RH ground circuit Blind spot monitor sensor LH

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.
Before measuring the resistance of the CAN bus, turn the engine switch off and leave the vehicle for 1 minute or more without operating the key or any switches, or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
After turning the engine switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.
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HINT:

Operating the engine switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.
Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.

PROCEDURE

CHECK DTC

(a) Check for DTCs.

Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Trouble Codes

Result	Proceed to
DTC U0232 is only output	A
DTC U0233 is only output	B
DTC U0232 and U0233 are output	C

GO TO STEP 5

GO TO STEP 8

2.	CHECK CAN BUS MAIN WIRE

(a) Disconnect the cable from the negative (-) battery terminal.

(b) Disconnect the R5 blind spot monitor sensor LH connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
R5-1 (CA2P) - R5-6 (CA2N)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

*a	Front view of wire harness connector (to blind spot monitor sensor LH)

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR LH - No. 24 JUNCTION CONNECTOR)

3.	CHECK HARNESS AND CONNECTOR (BLIND SPOT MONITOR SENSOR LH - BODY GROUND)

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REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR LH - No. 24 JUNCTION CONNECTOR)

4.	CHECK HARNESS AND CONNECTOR (BLIND SPOT MONITOR SENSOR LH POWER SOURCE)

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REPLACE BLIND SPOT MONITOR SENSOR LH

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.	CHECK CAN BUS MAIN WIRE

(a) Disconnect the cable from the negative (-) battery terminal.

(b) Disconnect the R4 blind spot monitor sensor RH connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
R4-1 (CA2P) - R4-6 (CA2N)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

*a	Front view of wire harness connector (to blind spot monitor sensor RH)

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR RH - No. 24 JUNCTION CONNECTOR)

6.	CHECK HARNESS AND CONNECTOR (BLIND SPOT MONITOR SENSOR RH - BODY GROUND)

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REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR RH - No. 24 JUNCTION CONNECTOR)

7.	CHECK HARNESS AND CONNECTOR (BLIND SPOT MONITOR SENSOR RH POWER SOURCE)

Click here

REPLACE BLIND SPOT MONITOR SENSOR RH

REPAIR OR REPLACE HARNESS OR CONNECTOR

8.	CHECK CAN BUS MAIN WIRE (BLIND SPOT MONITOR SENSOR LH)

(a) Turn the engine switch off.

(b) Disconnect the cable from the negative (-) battery terminal.

Standard Resistance:

Tester Connection	Condition	Specified Condition	Result
N100-1 (CANH) - N100-12 (CANL)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω	Below 54 Ω: Short circuit between bus lines
N100-1 (CANH) - N100-12 (CANL)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω	70 Ω or more: Open circuit in main bus lines
N100-1 (CANH) - G57-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Below 200 Ω: CANH short to ground
N100-12 (CANL) - G57-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Below 200 Ω: CANL short to ground
N100-1 (CANH) - G57-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Below 6 kΩ: CANH +B short
N100-12 (CANL) - G57-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Below 6 kΩ: CANL +B short

DLC3

Component with harness connected

(No. 24 Junction Connector)

Result	Proceed to
OK	A
Open circuit in CAN main bus lines	B
Short circuit between bus lines	C
Short to ground +B short	D

GO TO STEP 11

GO TO STEP 15

GO TO STEP 19

9.	CONFIRM CAN BUS WIRE (CLEARANCE WARNING ECU ASSEMBLY)

(a) Disconnect the N41 clearance warning ECU assembly connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
N41-37 (CANH) - N41-38 (CANL)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω

*a	Front view of wire harness connector (to clearance warning ECU assembly)

REPAIR OR REPLACE CAN BUS WIRE (CLEARANCE WARNING ECU ASSEMBLY - No. 24 JUNCTION CONNECTOR)

10.

CHECK DTC

(a) Clear the DTCs.

Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Clear DTCs

(b) Check for DTCs.

Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Trouble Codes

Result	Proceed to
DTC U0232 and U0233 are output	A
DTC U0232 and U0233 are not output	B

REPLACE CLEARANCE WARNING ECU ASSEMBLY

USE SIMULATION METHOD TO CHECK

11.	CHECK FOR OPEN IN CAN BUS WIRE (No. 24 JUNCTION CONNECTOR)

(a) Disconnect the N100 No. 24 junction connector.

*a	Front view of wire harness connector (to No. 24 Junction Connector)
*b	to blind spot monitor sensor RH CAN main wire
*c	to blind spot monitor sensor LH CAN main wire
*d	to clearance warning ECU assembly CAN wire

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
N100-3 (CANH) - N100-14 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω
N100-2 (CANH) - N100-13 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω
N100-1 (CANH) - N100-12 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

Result	Proceed to
OK	A
NG (to blind spot monitor sensor RH CAN main wire)	B
NG (to blind spot monitor sensor LH CAN main wire)	C
NG (to clearance warning ECU assembly CAN wire)	D

REPLACE No. 24 JUNCTION CONNECTOR

GO TO STEP 13

GO TO STEP 14

12.	CHECK FOR OPEN IN CAN BUS MAIN WIRE (BLIND SPOT MONITOR SENSOR RH)

(a) Reconnect the N100 No. 24 junction connector.

(b) Disconnect the R4 blind spot monitor sensor RH connector.

*a	Front view of wire harness connector (to blind spot monitor sensor RH)

Standard Resistance:

Tester Connection	Condition	Specified Condition
R4-1 (CA2P) - R4-6 (CA2N)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

REPLACE BLIND SPOT MONITOR SENSOR RH

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR RH - No. 24 JUNCTION CONNECTOR)

13.	CHECK FOR OPEN IN CAN BUS MAIN WIRE (BLIND SPOT MONITOR SENSOR LH)

(a) Reconnect the N100 No. 24 junction connector.

(b) Disconnect the R5 blind spot monitor sensor LH connector.

*a	Front view of wire harness connector (to blind spot monitor sensor LH)

Standard Resistance:

Tester Connection	Condition	Specified Condition
R5-1 (CA2P) - R5-6 (CA2N)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

REPLACE BLIND SPOT MONITOR SENSOR LH

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR LH - No. 24 JUNCTION CONNECTOR)

14.	CHECK FOR OPEN IN CAN BUS WIRE (CLEARANCE WARNING ECU ASSEMBLY)

(a) Reconnect the N100 No. 24 junction connector.

(b) Disconnect the N41 clearance warning ECU assembly connector.

*a	Front view of wire harness connector (to clearance warning ECU assembly)

Standard Resistance:

Tester Connection	Condition	Specified Condition
N41-37 (CANH) - N41-38 (CANL)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω

REPLACE CLEARANCE WARNING ECU ASSEMBLY

REPAIR OR REPLACE CAN BUS WIRE (CLEARANCE WARNING ECU ASSEMBLY - No. 24 JUNCTION CONNECTOR)

15.	CHECK FOR SHORT IN CAN BUS WIRES (No. 24 JUNCTION CONNECTOR)

(a) Disconnect the N100 No. 24 junction connector.

*a	Front view of wire harness connector (to No. 24 Junction Connector)
*b	to blind spot monitor sensor RH CAN main wire
*c	to blind spot monitor sensor LH CAN main wire
*d	to clearance warning ECU assembly CAN wire

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
N100-3 (CANH) - N100-14 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω
N100-2 (CANH) - N100-13 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω
N100-1 (CANH) - N100-12 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

Result	Proceed to
OK	A
NG (to blind spot monitor sensor RH CAN main wire)	B
NG (to blind spot monitor sensor LH CAN main wire)	C
NG (to clearance warning ECU assembly CAN wire)	D

REPLACE No. 24 JUNCTION CONNECTOR

GO TO STEP 17

GO TO STEP 18

16.	CHECK FOR SHORT IN CAN BUS WIRES (BLIND SPOT MONITOR SENSOR RH)

(a) Reconnect the N100 No. 24 junction connector.

(b) Disconnect the R4 blind spot monitor sensor RH connector.

*a	Front view of wire harness connector (to blind spot monitor sensor RH)

Standard Resistance:

Tester Connection	Condition	Specified Condition
R4-1 (CA2P) - R4-6 (CA2N)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

REPLACE BLIND SPOT MONITOR SENSOR RH

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR RH - No. 24 JUNCTION CONNECTOR)

17.	CHECK FOR SHORT IN CAN BUS WIRES (BLIND SPOT MONITOR SENSOR LH)

(a) Reconnect the N100 No. 24 junction connector.

(b) Disconnect the R5 blind spot monitor sensor LH connector.

*a	Front view of wire harness connector (to blind spot monitor sensor LH)

Standard Resistance:

Tester Connection	Condition	Specified Condition
R5-1 (CA2P) - R5-6 (CA2N)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

REPLACE BLIND SPOT MONITOR SENSOR LH

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR LH - No. 24 JUNCTION CONNECTOR)

18.	CHECK FOR SHORT IN CAN BUS WIRES (CLEARANCE WARNING ECU ASSEMBLY)

(a) Reconnect the N100 No. 24 junction connector.

(b) Disconnect the N41 clearance warning ECU assembly connector.

*a	Front view of wire harness connector (to clearance warning ECU assembly)

Standard Resistance:

Tester Connection	Condition	Specified Condition
N41-37 (CANH) - N41-38 (CANL)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω

REPLACE CLEARANCE WARNING ECU ASSEMBLY

REPAIR OR REPLACE CAN BUS WIRE (CLEARANCE WARNING ECU ASSEMBLY - No. 24 JUNCTION CONNECTOR)

19.	CHECK FOR SHORT IN CAN BUS WIRES (No. 24 JUNCTION CONNECTOR)

(a) Disconnect the N100 No. 24 junction connector.

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

DLC3

Front view of wire harness connector

(to No. 24 Junction Connector)

to blind spot monitor sensor RH CAN main wire

to blind spot monitor sensor LH CAN main wire

to clearance warning ECU assembly CAN wire

Standard Resistance:

Tester Connection	Condition	Specified Condition
N100-3 (CANH) - G57-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
N100-14 (CANL) - G57-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
N100-3 (CANH) - G57-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
N100-14 (CANL) - G57-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
N100-1 (CANH) - G57-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
N100-12 (CANL) - G57-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
N100-1 (CANH) - G57-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
N100-12 (CANL) - G57-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
N100-2 (CANH) - G57-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
N100-13 (CANL) - G57-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
N100-2 (CANH) - G57-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
N100-13 (CANL) - G57-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher

Result	Proceed to
OK	A
NG (to blind spot monitor sensor RH CAN main wire)	B
NG (to blind spot monitor sensor LH CAN main wire)	C
NG (to clearance warning ECU assembly CAN wire)	D

REPLACE No. 24 JUNCTION CONNECTOR

GO TO STEP 21

GO TO STEP 22

20.	CHECK FOR SHORT IN CAN BUS WIRES (BLIND SPOT MONITOR SENSOR RH)

(a) Reconnect the N100 No. 24 junction connector.

(b) Disconnect the R4 blind spot monitor sensor RH connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
R4-1 (CA2P) - G57-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
R4-6 (CA2N) - G57-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
R4-1 (CA2P) - G57-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
R4-6 (CA2N) - G57-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher

DLC3

Front view of wire harness connector

(to blind spot monitor sensor RH)

REPLACE BLIND SPOT MONITOR SENSOR RH

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR RH - No. 24 JUNCTION CONNECTOR)

21.	CHECK FOR SHORT IN CAN BUS WIRES (BLIND SPOT MONITOR SENSOR LH)

(a) Reconnect the N100 No. 24 junction connector.

(b) Disconnect the R5 blind spot monitor sensor LH connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
R5-1 (CA2P) - G57-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
R5-6 (CA2N) - G57-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
R5-1 (CA2P) - G57-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
R5-6 (CA2N) - G57-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher

DLC3

Front view of wire harness connector

(to blind spot monitor sensor LH)

REPLACE BLIND SPOT MONITOR SENSOR LH

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR LH - No. 24 JUNCTION CONNECTOR)

22.	CHECK FOR SHORT IN CAN BUS WIRES (CLEARANCE WARNING ECU ASSEMBLY)

(a) Reconnect the N100 No. 24 junction connector.

(b) Disconnect the N41 clearance warning ECU assembly connector.

DLC3

Front view of wire harness connector

(to clearance warning ECU assembly)

Standard Resistance:

Tester Connection	Condition	Specified Condition
N41-37 (CANH) - G57-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
N41-38 (CANL) - G57-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
N41-37 (CANH) - G57-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
N41-38 (CANL) - G57-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher

REPLACE CLEARANCE WARNING ECU ASSEMBLY

REPAIR OR REPLACE CAN BUS WIRE (CLEARANCE WARNING ECU ASSEMBLY - No. 24 JUNCTION CONNECTOR)

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