DESCRIPTION
Detection Item | Symptom | Trouble Area |
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Main Body ECU Communication Stop Mode | Either condition is met:
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WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
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HINT:
PROCEDURE
1. | CHECK FOR OPEN IN CAN BUS LINES (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) BRANCH LINE) |
(a) Disconnect the cable from the negative (-) battery terminal.
(b) Disconnect the J8 main body ECU (multiplex network body ECU) connector. |
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(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection | Condition | Specified Condition |
---|---|---|
J8-14 (CANH) - J8-13 (CANL) | Cable disconnected from negative (-) battery terminal | 54 to 69 Ω |
NG | ![]() | REPAIR OR REPLACE CAN BRANCH LINES OR CONNECTOR (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)) |
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2. | CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) |
(a) Remove the main body ECU (multiplex network body ECU).
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(b) Measure the resistance according to the value(s) in the table below. Standard Resistance:
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(c) Reconnect the cable to the negative (-) battery terminal.
(d) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Tester Connection | Condition | Specified Condition |
---|---|---|
MB-30 (ACC) - Body ground | Engine switch on (ACC) | 11 to 14 V |
MB-31 (BECU) - Body ground | Always | 11 to 14 V |
MB-32 (IG) - Body ground | Engine switch on (IG) | 11 to 14 V |
Result | Proceed to |
---|---|
OK | A |
NG (BECU) | B |
NG (ACC) | C |
NG (IG) | D |
NG (GND1) | E |
A | ![]() | REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) |
C | ![]() | GO TO LIGHTING (INT) SYSTEM (ACC SIGNAL CIRCUIT) |
D | ![]() | GO TO LIGHTING (INT) SYSTEM (IG SIGNAL CIRCUIT) |
E | ![]() | GO TO STEP 4 |
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3. | CHECK HARNESS AND CONNECTOR (BECU SIGNAL CIRCUIT) |
(a) Disconnect the 2C instrument panel junction block assembly connector.
(b) Measure the voltage according to the value(s) in the table below. Standard Voltage:
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OK | ![]() | REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY |
NG | ![]() | REPAIR OR REPLACE HARNESS OR CONNECTOR (BECU SIGNAL CIRCUIT) |
4. | CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT) |
(a) Disconnect the cable from the negative (-) battery terminal.
(b) Disconnect the 2B instrument panel junction block assembly connector.
(c) Measure the resistance according to the value(s) in the table below. Standard Resistance:
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OK | ![]() | REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY |
NG | ![]() | REPAIR OR REPLACE HARNESS OR CONNECTOR (GROUND CIRCUIT) |
Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Automatic Transaxle System: Initialization
INITIALIZATION RESET TRANSAXLE COMPENSATION CODE NOTICE:
If the following parts have been replaced, initialize the ECM and perform Reset Memory and Perform Road Test to Allow ECM to Learn.
ECM
Transmission valve body assembly
Shift solenoid valve SL3
Shift solenoid valve SL4
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Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Smart Access System With Push-button Start (for Start Function): Lost Communication with ECM / PCM (U0100,U0140,U0142,U0155,U1117)
DESCRIPTION These DTCs are stored when there is a CAN communication malfunction between the certification ECU (smart key ECU assembly), ECM, main body ECU (multiplex network body ECU) or combination meter assembly, and data from the option connector (bus buffer ECU) cannot be received. DTC No. ...