Dtc B1825/56 Short In Front Passenger Side - Side Squib Circuit

Lexus IS250 IS220d GSE20 ALE20 - SUPPLEMENTAL RESTRAINT SYSTEM

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK FRONT SEAT SIDE AIRBAG ASSEMBLY (FRONT PASSENGER SIDE - SIDE SQUIB)

CHECK FLOOR WIRE (FRONT PASSENGER SIDE - SIDE SQUIB CIRCUIT)

CHECK CENTER AIRBAG SENSOR ASSEMBLY

DTC B1825/56 Short in Front Passenger Side - Side Squib Circuit

DTC B1826/56 Open in Front Passenger Side - Side Squib Circuit

DTC B1827/56 Short to GND in Front Passenger Side - Side Squib Circuit

DTC B1828/56 Short to B+ in Front Passenger Side - Side Squib Circuit

DESCRIPTION

The front passenger side - side squib circuit consists of the center airbag sensor assembly and the front seat side airbag assembly (passenger side).


The circuit instructs the SRS to deploy when deployment conditions are met.


These DTCs are recorded when a malfunction is detected in the front passenger side - side squib circuit.

DTC No.DTC Detection ConditionTrouble Area
B1825/56
The center airbag sensor assembly receives a line short circuit signal 5 times in the front passenger side - side squib circuit during primary check.
Front passenger side - side squib malfunction
Center airbag sensor assembly malfunction
Floor wire
Front seat side airbag assembly (Front passenger side - side squib)
Center airbag sensor assembly
B1826/56
The center airbag sensor assembly receives an open circuit signal in the front passenger side - side squib circuit for 2 seconds.
Front passenger side - side squib malfunction
Center airbag sensor assembly malfunction
Floor wire
Front seat side airbag assembly (Front passenger side - side squib)
Center airbag sensor assembly
B1827/56
The center airbag sensor assembly receives a short circuit to ground signal in the front passenger side - side squib circuit for 0.5 seconds.
Front passenger side - side squib malfunction
Center airbag sensor assembly malfunction
Floor wire
Front seat side airbag assembly (Front passenger side - side squib)
Center airbag sensor assembly
B1828/56
The center airbag sensor assembly receives a short circuit to B+ signal in the front passenger side - side squib circuit for 0.5 seconds.
Front passenger side - side squib malfunction
Center airbag sensor assembly malfunction
Floor wire
Front seat side airbag assembly (Front passenger side - side squib)
Center airbag sensor assembly

WIRING DIAGRAM

Dtc B1825/56 Short In Front Passenger Side - Side Squib Circuit. SUPPLEMENTAL RESTRAINT SYSTEM. Lexus IS250 IS220d GSE20 ALE20

INSPECTION PROCEDURE

  • HINT:
Perform the simulation method by selecting the "check mode" (signal check) with the intelligent tester .
After selecting the "check mode" (signal check), perform the simulation method by wiggling each connector of the airbag system or driving the vehicle on a city or rough road .
1.CHECK FRONT SEAT SIDE AIRBAG ASSEMBLY (FRONT PASSENGER SIDE - SIDE SQUIB)
Dtc B1825/56 Short In Front Passenger Side - Side Squib Circuit. SUPPLEMENTAL RESTRAINT SYSTEM. Lexus IS250 IS220d GSE20 ALE20

Turn the engine switch off.

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

Disconnect the connector from the front seat side airbag assembly (front passenger side).

Connect the black wire side of SST (resistance 2.1 Ω) to connector "C".

  • CAUTION:
  • Never connect a tester to the front seat side airbag assembly (front passenger side - side squib) for measurement, as this may lead to a serious injury due to airbag deployment.
  • NOTICE:
Do not forcibly insert the SST into the terminals of the connector when connecting.
Insert straight the SST into the terminals of the connector.

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

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

Clear the DTCs stored in the memory .

Turn the engine switch off.

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

Check for DTCs .

  • OK:
  • DTC B1825, B1826, B1827, B1828 or 56 is not output.
  • HINT:
  • Codes other than DTC B1825, B1826, B1827, B1828 and 56 may be output at this time, but they are not related to this check.
NG
REPLACE FRONT SEAT ASSEMBLY (PASSENGER SIDE)
OK
2.CHECK FLOOR WIRE (FRONT PASSENGER SIDE - SIDE SQUIB CIRCUIT)
Dtc B1825/56 Short In Front Passenger Side - Side Squib Circuit. SUPPLEMENTAL RESTRAINT SYSTEM. Lexus IS250 IS220d GSE20 ALE20

Turn the engine switch off.

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

Disconnect the SST from connector "C".

Disconnect the connectors from the center airbag sensor assembly.

Check for a short to B+ in the circuit.


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

Turn the engine switch on (IG).

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

  • Standard voltage:
  • LHD:
  • Tester connectionConditionSpecified condition
    Pc1-1 (SFR+) - Body groundEngine switch on (IG)Below 1 V
    Pc1-2 (SFR-) - Body groundEngine switch on (IG)Below 1 V
  • RHD:
  • Tester connectionConditionSpecified condition
    Qd1-1 (SFL+) - Body groundEngine switch on (IG)Below 1 V
    Qd1-2 (SFL-) - Body groundEngine switch on (IG)Below 1 V

Check for an open in the circuit.


Turn the engine switch off.

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

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

  • Standard resistance:
  • LHD:
  • Tester connectionConditionSpecified condition
    Pc1-1 (SFR+) - Pc1-2 (SFR-)AlwaysBelow 1 Ω
  • RHD:
  • Tester connectionConditionSpecified condition
    Qd1-1 (SFL+) - Qd1-2 (SFL-)AlwaysBelow 1 Ω

Check for a short to ground in the circuit.


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

  • Standard resistance:
  • LHD:
  • Tester connectionConditionSpecified condition
    Pc1-1 (SFR+) - Body groundAlways1 MΩ or higher
    Pc1-2 (SFR-) - Body groundAlways1 MΩ or higher
  • RHD:
  • Tester connectionConditionSpecified condition
    Qd1-1 (SFL+) - Body groundAlways1 MΩ or higher
    Qd1-2 (SFL-) - Body groundAlways1 MΩ or higher

Check for a short in the circuit.


Release the activation prevention mechanism built into connector "B" .

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

  • Standard resistance:
  • LHD:
  • Tester connectionConditionSpecified condition
    Pc1-1 (SFR+) - Pc1-2 (SFR-)Always1 MΩ or higher
  • RHD:
  • Tester connectionConditionSpecified condition
    Qd1-1 (SFL+) - Qd1-2 (SFL-)Always1 MΩ or higher
NG
REPAIR OR REPLACE FLOOR WIRE
OK
3.CHECK CENTER AIRBAG SENSOR ASSEMBLY
Dtc B1825/56 Short In Front Passenger Side - Side Squib Circuit. SUPPLEMENTAL RESTRAINT SYSTEM. Lexus IS250 IS220d GSE20 ALE20

Connect the connectors to the front seat side airbag assembly (front passenger side) and the center airbag sensor assembly.

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

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

Clear the DTCs stored in the memory .

Turn the engine switch off.

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

Check for DTCs .

  • OK:
  • DTC B1825, B1826, B1827, B1828 or 56 is not output.
  • HINT:
  • Codes other than DTC B1825, B1826, B1827, B1828 and 56 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