Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: IG Signal Circuit
DESCRIPTION
This circuit detects the engine switch on (IG) or off condition, and sends it to the main body ECU (multiplex network body ECU).
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
- Inspect the fuses for circuits related to this system before performing the following procedure.
-
Before replacing the main body ECU (multiplex network body ECU), refer to Registration.
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PROCEDURE
| 1. | CHECK FOR DTC (SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Start Function)) |
(a) Clear the DTCs.
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(b) Check for DTCs.
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| Result | Proceed to |
|---|---|
| Smart Access System with Push-button Start (for Start Function) DTCs are not output | A |
| Smart Access System with Push-button Start (for Start Function) DTCs are output | B |
| B | .gif) | GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Start Function) |
|
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| 2. | READ VALUE USING TECHSTREAM |
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Body Electrical / Main Body / Data List.
(e) Read the Data List according to the display on the Techstream.
Body Electrical > Main Body > Data List| Tester Display | Measurement Item | Range | Normal Condition | Diagnostic Note |
|---|---|---|---|---|
| IG SW | Engine switch on (IG) signal | ON or OFF | ON: Engine switch on (IG) OFF: Engine switch off | - |
| Tester Display |
|---|
| IG SW |
OK:
Normal conditions listed above are displayed.
| OK | | PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
|
| 3. | CHECK HARNESS AND CONNECTOR (POWER SOURCE - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY) |
(a) Disconnect the 2E instrument panel junction block assembly connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| 2E-1 - Body ground | Always | 11 to 14 V |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 4. | INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY |
(a) Remove the instrument panel junction block assembly.
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(b) Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.
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(c) Measure the resistance according to the value(s) in the table below.
| *a | Component without harness connected (Instrument Panel Junction Block Assembly) | - | - |
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| 2E-1 - MB-32 (IG) | Battery not connected to 2A-17 and 2B-3 | 10 kΩ or higher |
| 2E-1 - MB-32 (IG) | Battery positive (+) → 2A-17 Battery negative (-) → 2B-3 | Below 1 Ω |
| OK | | REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) |
| NG | | REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY |
Data List / Active Test
DATA LIST / ACTIVE TEST DATA LIST NOTICE: In the following table, the values listed under "Normal Condition" are reference values. Do not depend solely on these reference values when deciding whether ...
ACC Signal Circuit
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Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual
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Lexus RX (RX 350L, RX450h) 2016-{YEAR} Repair Manual
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