Lexus IS250 · Service Manual RESTRAINTS

B1651/33

Diagnostic trouble codes

DESCRIPTION

The manual cut off switch circuit consists of the center airbag sensor assembly and the airbag cut off switch cylinder.
The front passenger airbag assembly, front passenger side knee airbag assembly and the front seat side airbag assembly (passenger side) can be optionally deactivated via this circuit by turning the manual cut off switch to the OFF position.
If the front passenger airbag assembly, front passenger side knee airbag assembly and the front seat side airbag assembly (passenger side) are deactivated, the passenger airbag ON/OFF indicator ("OFF") comes on to inform the passengers.
DTC B1651/33 is recorded when a malfunction is detected in the manual cut off switch circuit.
DTC No.
 DTC Detecting Condition
 Trouble Area
B1651/33
  1. The center airbag sensor assembly receives a line short circuit signal, an open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the manual cut off switch circuit for 2 seconds.
  2. Manual cut off switch malfunction
  3. Center airbag sensor assembly malfunction
  1. Instrument panel wire
  2. Airbag cut off switch cylinder
  3. Center airbag sensor assembly

WIRING DIAGRAM

H045137E03

INSPECTION PROCEDURE

HINT:
The "B" J47-11 (MSW+) and J47-12 (MSW-) connectors in this circuit have an activation prevention mechanism.
This mechanism can be used to check for an open circuit in the wire harness. In case of other checks (check for short, short to ground or short to B+), this mechanism should be released.


1. CHECK INSTRUMENT PANEL WIRE (OPEN)

  1. C123636E01
    Turn the engine switch off.

  1. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.

  1. Disconnect the connectors from the center airbag sensor assembly and the airbag cut off switch cylinder.

  1. Measure the resistance according to the value(s) in the table below.

    Standard resistance:
    Tester connection
    		 Condition
    		 Specified condition
    J91-2 (PMC+) - J91-1 (PMC-)
    		 Always
    		 Below 1 Ω



NG
REPAIR OR REPLACE INSTRUMENT PANEL WIRE
OK


2. CHECK INSTRUMENT PANEL WIRE (SHORT)

  1. C123637E01
    Release the activation prevention mechanism built into connector "B" (Click here).

  1. Measure the resistance according to the value(s) in the table below.

    Standard resistance:
    Tester connection
    		 Condition
    		 Specified condition
    J91-2 (PMC+) - J91-1 (PMC-)
    		 Always
    		 1 MΩ or higher



NG
REPAIR OR REPLACE INSTRUMENT PANEL WIRE
OK


3. CHECK INSTRUMENT PANEL WIRE (SHORT TO GROUND)

  1. C123637E01
    Measure the resistance according to the value(s) in the table below.

    Standard resistance:
    Tester connection
    		 Condition
    		 Specified condition
    J91-2 (PMC+) - Body ground
    		 Always
    		 1 MΩ or higher
    J91-1 (PMC-) - Body ground
    		 Always
    		 1 MΩ or higher



NG
REPAIR OR REPLACE INSTRUMENT PANEL WIRE
OK


4. CHECK INSTRUMENT PANEL WIRE (SHORT TO B+)

  1. C123637E01
    Connect the negative (-) terminal cable to the battery, and wait for at least 2 seconds.

  1. Turn the engine switch on (IG).

  1. Measure the voltage according to the value(s) in the table below.

    Standard voltage:
    Tester connection
    		 Condition
    		 Specified condition
    J91-2 (PMC+) - Body ground
    		 Engine switch on (IG)
    		 Below 1 V
    J91-1 (PMC-) - Body ground
    		 Engine switch on (IG)
    		 Below 1 V



NG
REPAIR OR REPLACE INSTRUMENT PANEL WIRE
OK


5. CHECK AIRBAG CUT OFF SWITCH CYLINDER

  1. H045136E02
    Turn the engine switch off.

  1. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.

  1. Measure the resistance according to the value(s) in the table below.

    Standard resistance:
    Tester connection
    		 Manual cut off switch condition
    		 Specified condition
    J91-2 (PMC+) - J91-1 (PMC-)
    		 Cut off switch is in ON position (Front passenger side airbag is active)
    		 360 to 440 Ω
    J91-2 (PMC+) - J91-1 (PMC-)
    		 Cut off switch is in OFF position (Front passenger side airbag is not active)
    		 90 to 110 Ω



NG
REPLACE AIRBAG CUT OFF SWITCH CYLINDER
OK


6. CHECK CENTER AIRBAG SENSOR ASSEMBLY

  1. C123638E01
    Connect the connectors to the center airbag sensor assembly and the airbag cut off switch cylinder.

  1. Connect the negative (-) terminal cable to the battery, and wait for at least 2 seconds.

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

  1. Clear the DTCs stored in memory (Click here).

  1. Turn the engine switch off.

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

  1. Check for DTCs (Click here).

    OK:
    DTC B1651/33 is not output.

    HINT:
    Codes other than DTC B1651/33 may be output at this time, but they are not related to this check.



 NG
REPLACE CENTER AIRBAG SENSOR ASSEMBLY
OK

USE SIMULATION METHOD TO CHECK


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