Lexus NX: Driver Side Seat Position Sensor (B1653)
DESCRIPTION
The seat position airbag sensor circuit consists of the airbag ECU assembly and seat position airbag sensor.
DTC B1653 is stored when a malfunction is detected in the seat position airbag sensor circuit.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area |
|---|---|---|---|
| B1653 | Driver Side Seat Position Sensor | One of the following conditions is met:
|
|
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
-
After the power switch is turned off, there may be a waiting time before disconnecting 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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-
After replacing the airbag ECU assembly, refer to initialization.
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PROCEDURE
| 1. | CHECK CONNECTION OF CONNECTORS |
(a) Turn the power switch off.
(b) Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 90 seconds.
(c) Check that the connectors are properly connected to the airbag ECU assembly and seat position airbag sensor.
| Connectors are not properly connected | .gif) | CONNECT CONNECTORS PROPERLY |
|
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| 2. | CHECK CONNECTORS |
| (a) Disconnect the connectors from the airbag ECU assembly and seat position airbag sensor. |
|
(b) Check that the connectors (on the airbag ECU assembly side and seat position airbag sensor side) are not damaged.
| Connectors are deformed or damaged | | REPLACE NO. 2 FLOOR WIRE OR FRONT SEAT INNER BELT ASSEMBLY LH |
|
| 3. | CHECK SEAT POSITION AIRBAG SENSOR CIRCUIT |
(a) Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.
| *1 | Seat Position Airbag Sensor | *2 | Airbag ECU Assembly |
| *3 | Connector E | *4 | Connector B |
| *5 | Service Wire | - | - |
| *a | Front view of wire harness connector (to Seat Position Airbag Sensor) | *b | Rear view of wire harness connector (to Airbag ECU Assembly) |
(b) Turn the power switch on (IG).
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Switch Condition | Specified Condition |
|---|---|---|
| 1 (LSP-) - Body ground | Power switch on (IG) | Below 1 V |
| 2 (LSP+) - Body ground | Power switch on (IG) | Below 1 V |
(d) Turn the power switch off.
(e) Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 90 seconds.
(f) Using a service wire, connect terminals 24 (LSP-) and 16 (LSP+) of connector B.
NOTICE:
Do not forcibly insert the service wire into the terminals of the connector when connecting a service wire.
(g) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| 1 (LSP-) - 2 (LSP+) | Always | Below 1 Ω |
(h) Disconnect the service wire from connector B.
(i) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| 1 (LSP-) - 2 (LSP+) | Always | 1 MΩ or higher |
| 1 (LSP-) - Body ground | Always | 1 MΩ or higher |
| 2 (LSP+) - Body ground | Always | 1 MΩ or higher |
| NG | | GO TO STEP 7 |
|
| 4. | CHECK DTC |
| (a) Connect the connectors to the airbag ECU assembly and seat position airbag sensor. |
|
(b) Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.
(c) Turn the power switch on (IG), and wait for at least 60 seconds.
(d) Clear the DTCs.
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(e) Turn the power switch off.
(f) Turn the power switch on (IG), and wait for at least 60 seconds.
(g) Check for DTCs.
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HINT:
Codes other than DTC B1653 may be output at this time, but they are not related to this check.
| DTC B1653 is not output | | USE SIMULATION METHOD TO CHECK |
|
| 5. | REPLACE SEAT POSITION AIRBAG SENSOR |
(a) Turn the power switch off.
(b) Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 90 seconds.
(c) Replace the seat position airbag sensor.
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HINT:
Perform the inspection using parts from a normal vehicle if possible.
|
| 6. | CHECK DTC |
| (a) Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds. |
|
(b) Turn the power switch on (IG), and wait for at least 60 seconds.
(c) Clear the DTCs.
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(d) Turn the power switch off.
(e) Turn the power switch on (IG), and wait for at least 60 seconds.
(f) Check for DTCs.
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HINT:
Codes other than DTC B1653 may be output at this time, but they are not related to this check.
| DTC B1653 is not output | | END (SEAT POSITION AIRBAG SENSOR WAS DEFECTIVE) |
| DTC B1653 is output | | REPLACE AIRBAG ECU ASSEMBLY |
| 7. | CHECK NO. 2 FLOOR WIRE |
(a) Disconnect the No. 2 floor wire connector from the front seat inner belt assembly LH.
| *1 | Seat Position Airbag Sensor | *2 | Airbag ECU Assembly |
| *3 | Front Seat Inner Belt Assembly LH | *4 | No. 2 Floor Wire |
| *5 | Connector C | *6 | Connector B |
| *7 | Service Wire | - | - |
| *a | Front view of wire harness connector (to Front Seat Inner Belt Assembly LH) | *b | Rear view of wire harness connector (to Airbag ECU Assembly) |
(b) Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.
(c) Turn the power switch on (IG).
(d) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Switch Condition | Specified Condition |
|---|---|---|
| Q45-4 (LSP+) - Body ground | Power switch on (IG) | Below 1 V |
| Q45-3 (LSP-) - Body ground | Power switch on (IG) | Below 1 V |
(e) Turn the power switch off.
(f) Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 90 seconds.
(g) Using a service wire, connect terminals 24 (LSP-) and 16 (LSP+) of connector B.
NOTICE:
Do not forcibly insert the service wire into the terminals of the connector when connecting a service wire.
(h) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| Q45-4 (LSP+) - Q45-3 (LSP-) | Always | Below 1 Ω |
(i) Disconnect the service wire from connector B.
(j) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| Q45-4 (LSP+) - Q45-3 (LSP-) | Always | 1 MΩ or higher |
| Q45-4 (LSP+) - Body ground | Always | 1 MΩ or higher |
| Q45-3 (LSP-) - Body ground | Always | 1 MΩ or higher |
| OK | | REPLACE FRONT SEAT INNER BELT ASSEMBLY LH |
| NG | | REPLACE NO. 2 FLOOR WIRE |
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