Home Vehicle Interior Supplemental Restraint Systems AIRBAG SYSTEM
Last Modified: 11-27-2007 1.6 C
Service Category: Vehicle Interior Section: Supplemental Restraint Systems
Model Year: 2008 Model: LX570 Doc ID: RM0000038E8003X
Title: SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: DESCRIPTION (2008 LX570)

DTC

B1840/59

Short in Curtain Shield Squib RH 2nd Step Circuit

DTC

B1841/59

Open in Curtain Shield Squib RH 2nd Step Circuit

DTC

B1842/59

Short to GND in Curtain Shield Squib RH 2nd Step Circuit

DTC

B1843/59

Short to B+ in Curtain Shield Squib RH 2nd Step Circuit

DESCRIPTION

The curtain shield squib RH 2nd step circuit consists of the center airbag sensor and the curtain shield airbag RH.

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

These DTCs are stored when a malfunction is detected in the rear curtain shield squib RH 2nd step circuit.

DTC Code

DTC Detection Condition

Trouble Area

B1840/59

When one of the following conditions is met:

  • The center airbag sensor receives a line short circuit signal 5 times in the curtain shield squib RH 2nd step circuit during the primary check.
  • A curtain shield squib RH 2nd step malfunction.
  • A center airbag sensor malfunction.
  • No. 2 floor wire
  • Curtain shield airbag assembly RH (Curtain shield squib RH 2nd step)
  • Center airbag sensor assembly

B1841/59

When one of the following conditions is met:

  • The center airbag sensor receives an open circuit signal in the curtain shield squib RH 2nd step circuit for 2 seconds.
  • A curtain shield squib RH 2nd step malfunction.
  • A center airbag sensor malfunction.
  • No. 2 floor wire
  • Curtain shield airbag assembly RH (Curtain shield squib RH 2nd step)
  • Center airbag sensor assembly

B1842/59

When one of the following conditions is met:

  • The center airbag sensor receives a short circuit to ground signal in the curtain shield squib RH 2nd step circuit for 0.5 seconds.
  • A curtain shield squib RH 2nd step malfunction.
  • A center airbag sensor malfunction.
  • No. 2 floor wire
  • Curtain shield airbag assembly RH (Curtain shield squib RH 2nd step)
  • Center airbag sensor assembly

B1843/59

When one of the following conditions is met:

  • The center airbag sensor receives a short circuit to B+ signal in the curtain shield squib RH 2nd step circuit for 0.5 seconds.
  • A curtain shield squib RH 2nd step malfunction.
  • A center airbag sensor malfunction.
  • No. 2 floor wire
  • Curtain shield airbag assembly RH (Curtain shield squib RH 2nd step)
  • Center airbag sensor assembly

WIRING DIAGRAM



INSPECTION PROCEDURE

HINT:

To perform the simulation method, enter the "check mode (signal check) with the Techstream SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: CHECK MODE PROCEDURE (2008 LX570) , and then wiggle each connector of the airbag system or drive the vehicle on various type of road SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: DIAGNOSIS SYSTEM (2008 LX570) .

PROCEDURE

1.

CHECK CURTAIN SHIELD AIRBAG RH (CURTAIN SHIELD SQUIB RH 2ND STEP)



(a) Turn the engine switch off.

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

(c) Disconnect the connector from the curtain shield squib RH 2nd step.

(d) Connect the white wire side of SST (resistance: 2.1 Ω) to connector C.

CAUTION:

Never connect the tester to the curtain shield airbag RH (curtain shield squib RH 2nd step) for measurement, as this may lead to a serious injury due to airbag deployment.

NOTICE:

  • Do not forcibly insert SST into the terminals of the connector when connecting SST.
  • Insert SST straight into the terminals of the connector.

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

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

(g) Clear the DTCs SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: DTC CHECK / CLEAR (2008 LX570) .

(h) Turn the engine switch off.

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

(j) Check for DTCs SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: DTC CHECK / CLEAR (2008 LX570) .

OK:

DTC B1840, B1841, B1842 or B1843 is not output.

HINT:

Codes other than DTC B1840, B1841, B1842 and B1843 may be output at this time, but they are not related to this check.

OK

2.

CHECK CONNECTOR

(a) Turn the engine switch off.

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

(c) Disconnect SST from connector C.

(d) Check that the No. 2 floor wire connector (on the curtain shield squib RH 2nd step side) is not damaged.

OK:

The lock button is not disengaged, and the claw of the lock is not deformed or damaged.

OK

3.

CHECK NO. 2 FLOOR WIRE (CURTAIN SHIELD SQUIB RH 2ND STEP CIRCUIT)



(a) Disconnect the connectors from the center airbag sensor.

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

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

L20-1 (CR2+) - Body ground

Engine switch on (IG)

Below 1 V

L20-2 (CR2-) - Body ground

Engine switch on (IG)

Below 1 V

(d) Turn the engine switch off.

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

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

L20-1 (CR2+) - L20-2 (CR2-)

Always

Below 1 Ω

(g) Release the activation prevention mechanism built into connector B SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: DIAGNOSIS SYSTEM (2008 LX570) .

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

L20-1 (CR2+) - L20-2 (CR2-)

Always

1 MΩ or higher

L20-1 (CR2+) - Body ground

Always

1 MΩ or higher

L20-2 (CR2-) - Body ground

Always

1 MΩ or higher

OK

4.

CHECK CENTER AIRBAG SENSOR



(a) Connect the connectors to the curtain shield squib RH 2nd step and the center airbag sensor.

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

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

(d) Clear the DTCs SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: DTC CHECK / CLEAR (2008 LX570) .

(e) Turn the engine switch off.

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

(g) Check for DTCs SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: DTC CHECK / CLEAR (2008 LX570) .

OK:

DTC B1840, B1841, B1842 or B1843 is not output.

HINT:

Codes other than DTC B1840, B1841, B1842 and B1843 may be output at this time, but they are not related to this check.

OK