Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Pressure Sensor Difference for Front Door (B166A)

DESCRIPTION

The door side airbag sensor LH and door side airbag sensor RH detect impacts to the vehicle through changes in pressure inside the front doors caused by deformation of the outer side of the front doors and send signals to the airbag sensor assembly.

Based on the signals sent by the door side airbag sensors, the airbag sensor assembly determines if the airbags, pretensioners and selectable force limiter should be deployed.

If the difference between the pressure detected by the door side airbag sensor LH and the pressure detected by the door side airbag sensor RH exceeds a certain value a certain number of times, the airbag sensor assembly will store DTC B166A.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Warning Indicate	Test Mode / Check Mode
B166A	Pressure Sensor Difference for Front Door	The difference between the pressure detected by the door side airbag sensor LH and the door side airbag sensor RH exceeds a certain value a certain number of times.	Door side airbag sensor LH Door side airbag sensor RH Airbag sensor assembly	Comes on	Does not apply to test/check mode

CAUTION / NOTICE / HINT

NOTICE:

After turning the engine switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.

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PROCEDURE

1.

CHECK DTC

(a) Check for DTCs.

Body Electrical > SRS Airbag > Trouble Codes

OK:

DTCs B1633, B1642, B1643, B166D, B166E, B1638, B1647, B1648, B167B and B167C are not output.

HINT:

If DTC B1633, B1642, B1643, B166D, B166E, B1638, B1647, B1648, B167B or B167C is output, perform troubleshooting for the DTC first.

NG

GO TO DIAGNOSTIC TROUBLE CODE CHART

OK

2.	CHECK DOOR SIDE AIRBAG SENSOR LH

(a) Turn the engine switch off.

(b) Disconnect the cable from the negative (-) battery terminal.

CAUTION:

Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

(c) Replace the door side airbag sensor LH with a known good one.

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HINT:

Perform the following inspection using known good parts from another vehicle if possible.

(d) Connect the cable to the negative (-) battery terminal.

(e) Turn the engine switch on (IG), and wait for at least 60 seconds.

(f) Clear the DTCs stored in memory.

Body Electrical > SRS Airbag > Clear DTCs

(g) Turn the engine switch off.

(h) Turn the engine switch on (IG), and wait for at least 60 seconds.

(i) Check for DTCs.

Body Electrical > SRS Airbag > Trouble Codes

OK:

DTC B166A is not output.

HINT:

Codes other than DTC B166A may be output at this time, but they are not related to this check.

(j) Turn the engine switch off.

(k) Disconnect the cable from the negative (-) battery terminal.

CAUTION:

Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

(l) Restore the door side airbag sensor LH that was installed for testing to its original location.

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OK

REPLACE DOOR SIDE AIRBAG SENSOR LH

NG

3.	CHECK DOOR SIDE AIRBAG SENSOR RH

(a) Replace the door side airbag sensor RH with a known good one.

Click here

HINT:

Perform the following inspection using known good parts from another vehicle if possible.

(b) Connect the cable to the negative (-) battery terminal.

(c) Turn the engine switch on (IG), and wait for at least 60 seconds.

(d) Clear the DTCs stored in memory.

Body Electrical > SRS Airbag > Clear DTCs

(e) Turn the engine switch off.

(f) Turn the engine switch on (IG), and wait for at least 60 seconds.

(g) Check for DTCs.

Body Electrical > SRS Airbag > Trouble Codes

OK:

DTC B166A is not output.

HINT:

Codes other than DTC B166A may be output at this time, but they are not related to this check.

(h) Turn the engine switch off.

(i) Disconnect the cable from the negative (-) battery terminal.

CAUTION:

Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

(j) Restore the door side airbag sensor RH that was installed for testing to its original location.

Click here

OK

REPLACE DOOR SIDE AIRBAG SENSOR RH

NG

REPLACE AIRBAG SENSOR ASSEMBLY