Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Emission Gas NOx Sensor Circuit (B1461/61)
DESCRIPTION
The smog ventilation sensor is installed to the front of the cooler condenser assembly to automatically control the air inlet mode (fresh, recirculation/fresh, and recirculation).
This sensor detects NOx in the ambient air and transmits signals to the air conditioning amplifier assembly.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | Memory |
|---|---|---|---|---|
| B1461/61 | Emission Gas NOx Sensor Circuit | Open or short in emission gas NOx sensor circuit (w/ Smog Ventilation Sensor) |
| - |
WIRING DIAGRAM
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CAUTION / NOTICE / HINT
NOTICE:
- Inspect the fuses for circuits related to this system before performing the following procedure.
- If DTCs B1418/18 and B1461/61 are stored simultaneously, there may be a malfunction in the smog ventilation sensor power source circuit.
PROCEDURE
| 1. | READ VALUE USING TECHSTREAM |
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Allow exhaust gas (NOx) to travel to the sensing portion of the smog ventilation sensor.
(e) Enter the following menus: Body Electrical / Air Conditioner / Data List.
(f) Read the Data List according to the display on the Techstream.
Body Electrical > Air Conditioner > Data List| Tester Display | Measurement Item | Range | Normal Condition | Diagnostic Note |
|---|---|---|---|---|
| Emission Gas Nox Sensor | Emission gas (NOx) | Min.: 0 Max.: 255 | Smog ventilation sensor value increases as gas amount increases | - |
| Tester Display |
|---|
| Emission Gas Nox Sensor |
OK:
The display is as specified in the normal condition column.
| Result | Proceed to |
|---|---|
| NG | A |
| OK (When troubleshooting according to Problem Symptoms Table) | B |
| OK (When troubleshooting according to the DTC) | C |
| B | .gif) | PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
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| C | | REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY |
|
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| 2. | CHECK HARNESS AND CONNECTOR (SMOG VENTILATION SENSOR - IG POWER SOURCE AND BODY GROUND) |
(a) Disconnect the A71 smog ventilation sensor connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| A71-3 (IG) - Body ground | Engine switch on (IG) | 11 to 14 V |
| A71-3 (IG) - Body ground | Engine switch off | Below 1 V |
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| A71-6 (E) - Body ground | Always | Below 1 Ω |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 3. | CHECK HARNESS AND CONNECTOR (SMOG VENTILATION SENSOR - AIR CONDITIONING AMPLIFIER ASSEMBLY) |
(a) Disconnect the J42 air conditioning amplifier assembly connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| A71-1 (SG) - J42-2 (SG-2) | Always | Below 1 Ω |
| A71-4 (DGS1) - J42-27 (DGS1) | Always | Below 1 Ω |
| J42-2 (SG-2) or A71-1 (SG) - Body ground | Always | 10 kΩ or higher |
| J42-27 (DGS1) or A71-4 (DGS1) - Body ground | Always | 10 kΩ or higher |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 4. | INSPECT SMOG VENTILATION SENSOR |
| (a) Remove the smog ventilation sensor. Click here |
|
(b) Connect a positive (+) lead from the battery to terminal 3 (IG) and a negative (-) lead to terminal 6 (E).
(c) Allow exhaust gas (NOx) to travel to the sensing portion of the smog ventilation sensor, and measure the resistance between terminals 1 (SG) and 4 (DGS1).
OK:
When the sensor is exposed to exhaust gas, the resistance increases.
HINT:
The resistance of the sensor before being exposed to exhaust gas is 10 kΩ to 40 kΩ.
| OK | | REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY |
| NG | | REPLACE SMOG VENTILATION SENSOR |
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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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