Lexus NX: Parking Assist ECU Communication Stop Mode

Lexus NX Service Manual / Power Source & Network / Networking / Can Communication System / Parking Assist ECU Communication Stop Mode

DESCRIPTION

Detection Item	Symptom	Trouble Area
Parking Assist ECU Communication Stop Mode	Any of the following conditions are met: Communication stop for "Panoramic View Monitor / Circumference Monitoring Camera Control Module" is indicated on "Communication Bus Check". Click here Communication system DTCs (DTCs that start with U) that are output correspond to "Parking Assist ECU Communication Stop Mode" in "DTC Combination Table". Click here	Parking assist ECU branch wire or connector Power source circuit of parking assist ECU Parking assist ECU CAN branch wire or connector Parking assist ECU

WIRING DIAGRAM

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

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 power switch off and leave the vehicle for 1 minute or more without operating the key, switches or opening or closing the doors. After that, disconnect the cable from the negative (-) auxiliary battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal.
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When disconnecting and reconnecting the auxiliary battery.
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HINT:

When disconnecting and reconnecting the auxiliary battery, there is an automatic learning function that completes learning when the respective system is used.

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Some parts must be initialized and set when replacing or removing and installing parts.
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Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.
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After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.
DTC check procedure: Turn the power switch on (IG), wait for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes or more.
After the repair, perform CAN Bus Check and check that all the ECUs and sensors connected to the CAN communication system are displayed as normal.
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HINT:

Operating the power switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.
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

1.	CHECK FOR OPEN IN CAN BUS WIRE (PARKING ASSIST ECU CAN BRANCH WIRE)

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

(b) Disconnect the parking assist ECU connector.

*a	Front view of wire harness connector (to Parking Assist ECU)

Standard Resistance:

Tester Connection	Condition	Specified Condition
P44-11 (CANH) - P44-12 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	54 to 69 Ω

REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR

2.	CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
P44-4 (GND1) - Body ground	Cable disconnected from negative (-) auxiliary battery terminal	Below 1 Ω

*a	Front view of wire harness connector (to Parking Assist ECU)

(b) Reconnect the cable to the negative (-) auxiliary battery terminal.

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
P44-1 (+B) - Body ground	Power switch off	11 to 14 V
P44-2 (ACC) - Body ground	Power switch on (ACC)	11 to 14 V
P44-2 (ACC) - Body ground	Power switch off	Below 1 V
P44-3 (IG) - Body ground	Power switch on (IG)	11 to 14 V
P44-3 (IG) - Body ground	Power switch off	Below 1 V

REPLACE PARKING ASSIST ECU

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

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Lexus NX: Parking Assist ECU Communication Stop Mode

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