Airbag System (Diagnostic Codes & Symptom Tests): Overview Lexus LX J200

DESCRIPTION

The center airbag sensor consists of the airbag sensor, the safing sensor, the drive circuit, the diagnosis circuit, the ignition control, etc.

If the center airbag sensor receives signals from the airbag sensor, it determines whether the SRS should be activated.

DTC B1000/31 is output when a malfunction is detected in the center airbag sensor.

HINT

When a trouble code is output simultaneously with B1000/31, repair the malfunction indicated by the other code first.

The front airbag sensor RH circuit consists of the center airbag sensor and front airbag sensor RH.

The front airbag sensor RH detects impacts to the vehicle and sends signals to the center airbag sensor to determine if the airbag should be deployed.

DTC B1603/83, B1612/83 or B1613/83 is stored when a malfunction is detected in the front airbag sensor RH circuit.

Scheme 206

The front airbag sensor LH circuit consists of the center airbag sensor and front airbag sensor LH.

The front airbag sensor LH detects impacts to the vehicle and sends signals to the center airbag sensor to determine if the airbag should be deployed.

DTC B1608/84, B1617/84 or B1618/84 is stored when a malfunction is detected in the front airbag sensor LH circuit.

Scheme 207

The front airbag sensor RH consists of the diagnostic circuit and the frontal deceleration sensor, etc.

If the center airbag sensor receives signals from the frontal deceleration sensor, it determines whether the SRS should be activated.

DTC B1610/13 is stored when a malfunction is detected in the front airbag sensor RH circuit.

Scheme 208

The front airbag sensor LH consists of the diagnostic circuit and the frontal deceleration sensor, etc.

If the center airbag sensor receives signals from the frontal deceleration sensor, it determines whether the SRS should be activated.

DTC B1615/14 is stored when a malfunction is detected in the front airbag sensor LH circuit.

Scheme 209

HINT

"Door side airbag sensor LH" refers to the side airbag sensor LH.

1. The side airbag sensor LH or rear airbag sensor RH consists of the safing sensor, the diagnostic circuit, the lateral deceleration sensor, etc. If the center airbag sensor receives signals from the lateral deceleration sensor, it determines whether the SRS should be activated. DTC B1630/23 or B1695/16 is stored when a malfunction is detected in the side airbag sensor LH or rear airbag sensor RH circuit.

Scheme 210

Scheme 211

HINT

"Door side airbag sensor LH" refers to the side airbag sensor LH.

1. The circuit for the side collision sensor LH or RH (to determine deployment of the front seat airbag LH or RH, rear seat side airbag LH or RH and curtain shield airbag LH or RH) is composed of the center airbag sensor, side airbag sensor LH or RH, and rear airbag sensor LH or RH. The side airbag sensor LH or RH and rear airbag sensor LH or RH detect impacts to the vehicle and send signals to the center airbag sensor to determine if the airbag should be deployed. DTC B1632/81 or B1697/82 is stored when a malfunction is detected in the circuit for the side collision sensor LH or RH (to determine deployment of the front seat airbag LH or RH, rear seat side airbag LH or RH and curtain shield airbag LH or RH).

Scheme 212

Scheme 213

HINT

"Door side airbag sensor RH" refers to the side airbag sensor RH.

1. For DTC B1690 and B1635: The rear airbag sensor LH and side airbag sensor RH consists of the safing sensor, the diagnostic circuit, the lateral deceleration sensor, etc. If the center airbag sensor receives signals from the lateral deceleration sensor, it determines whether the SRS should be activated. DTC B1690/15 or B1635/24 is stored when a malfunction is detected in the rear airbag sensor LH or side airbag sensor RH circuit.
2. For DTC B1692 and B1637: The circuit for the side collision sensor RH or LH (to determine deployment of the front seat airbag RH or LH, rear seat side airbag RH or LH and curtain shield airbag RH or LH) is composed of the center airbag sensor, side airbag sensor RH or LH, and rear airbag sensor RH or LH. The side airbag sensor RH or LH, and rear airbag sensor RH or LH detect impacts to the vehicle and send signals to the center airbag sensor to determine if the airbag should be deployed. DTC B1692 or B1637 is stored when a malfunction is detected in the circuit for the side collision sensor RH or LH (to determine deployment of the front seat airbag RH or LH, rear seat side airbag RH or LH, and curtain shield airbag RH or LH).

HINT

"Door side airbag sensor RH" refers to the side airbag sensor RH.

1. The circuit for the side collision sensor LH or RH (to determine deployment of the front seat airbag LH or RH, rear seat side airbag LH or RH and curtain shield airbag LH or RH) is composed of the center airbag sensor, side airbag sensor LH or RH, and rear airbag sensor LH or RH. The side airbag sensor LH or RH and rear airbag sensor LH or RH detect impacts to the vehicle and send signals to the center airbag sensor to determine if the airbag should be deployed. DTC B1693/81 or B1648/82 is stored when a malfunction is detected in the circuit for the side collision sensor LH or RH (to determine deployment of the front seat airbag LH or RH and curtain shield airbag LH or RH). DTC B1643/81 or B1638/82 is stored when a malfunction is detected in the circuit for the rear collision sensor LH or RH (to determine deployment of the rear seat side airbag LH or RH and curtain shield airbag LH or RH).

The circuit for the side collision sensor LH or RH (to determine deployment of the front seat airbag LH or RH, rear seat side airbag LH or RH, and curtain shield airbag LH or RH) is composed of the center airbag sensor, side airbag sensor LH or RH, and rear airbag sensor LH or RH.

The side airbag sensor LH or RH, and rear airbag sensor LH or RH detect impacts to the vehicle and send signals to the center airbag sensor to determine if the airbag should be deployed.

DTC B1642/81 or B1647/82 is stored when a malfunction is detected in the circuit for the side collision sensor LH or RH (to determine deployment of the front seat airbag LH or RH, rear seat side airbag LH or RH and curtain shield airbag LH or RH).

The occupant classification system circuit consists of the center airbag sensor and the occupant classification system.

If the center airbag sensor receives signals from the occupant classification ECU, it determines whether the front passenger airbag, the front seat airbag RH and front seat outer belt should be operated.

DTC B1650/32 is stored when a malfunction is detected in the occupant classification system circuit.

Scheme 214

The seat position sensor circuit consists of the center airbag sensor and the seat position sensor.

DTC B1653/35 is stored when a malfunction is detected in the seat position sensor circuit.

Scheme 215

The seat belt buckle switch LH circuit consists of the center airbag sensor and the front seat inner belt LH.

DTC B1655/37 is stored when a malfunction is detected in the seat belt buckle switch LH circuit.

Scheme 216

The passenger airbag ON/OFF indicator circuit consists of the center airbag sensor and the passenger airbag ON/OFF indicator.

The passenger airbag ON/OFF indicator indicates the operation condition of the front passenger airbag, front passenger side knee airbag, front seat airbag RH and front seat outer belt RH.

DTC B1660/43 is stored when a malfunction is detected in the passenger airbag ON/OFF indicator circuit.

Scheme 217

The curtain shield airbag cutoff switch is a mechanism that operates both the right and left sides of the curtain shield airbag and the front seat outer belt when the center airbag sensor detects a roll-over.

The RSCA OFF indicator is installed in the combination meter.

If the curtain shield airbag cutoff switch is operated, the indicator comes on to inform the drive that the roll-over detection system is not working.

The initial setting of the roll-over detection system is on. It automatically operates every time the engine switch is turned on (IG).

Scheme 218

The indicator light circuit consists of the center airbag sensor and the combination meter.

When the center airbag sensor detects a malfunction in the SRS airbag system, the SRS warning light comes on to inform the driver. It also comes on when the source voltage drops, and automatically goes off in approximately 10 seconds after the source voltage returns to normal (DTC is not stored).

The SRS warning light comes on for 6 seconds after the engine switch is turned on (IG) and goes off if the system is normal.

When an open circuit is detected, such as when the connector between the combination meter and the center airbag sensor is disconnected, the SRS warning light remains on even when approximately 6 seconds elapsed after the engine switch is turned on (IG).

DTC B1662/45 is stored when a malfunction is detected in the indicator light circuit.

Scheme 219

The rear floor airbag sensor consists of the diagnostic circuit, the rear floor deceleration sensor, etc.

If the center airbag sensor receives signals from the rear floor deceleration sensor, it determines whether the SRS should be activated.

DTC B1675/82 is stored when a malfunction is detected in the rear floor airbag sensor circuit.

Scheme 220

HINT

"Rear floor airbag sensor RH" refers to the rear floor airbag sensor.

1. The rear floor airbag sensor circuit consists of the center airbag sensor and rear floor airbag sensor. The rear floor airbag sensor detects impacts to the vehicle and sends signals to the center airbag sensor to determine if the airbag should be deployed. DTC B1676/85, B1677/85 or B1694/85 is stored when a malfunction is detected in the rear floor airbag sensor circuit.

1. The driver side squib circuit consists of the center airbag sensor, the spiral cable, and the steering pad.
2. The circuit instructs the SRS to deploy when deployment conditions are met.
3. These DTCs are stored when a malfunction is detected in the driver side squib circuit.

Scheme 221

The front passenger side squib circuit consists of the center airbag sensor and the front passenger airbag.

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

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

Scheme 222

The driver side squib 2nd step circuit consists of the center airbag sensor, the spiral cable, and the steering pad.

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

These DTCs are stored when a malfunction is detected in the driver side squib 2nd step circuit.

Scheme 223

The front passenger side squib 2nd step circuit consists of the center airbag sensor and the front passenger airbag.

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

These DTCs are stored when a malfunction is detected in the front passenger side squib 2nd step circuit.

Scheme 224

The side squib RH circuit consists of the center airbag sensor and the front seat airbag RH.

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

These DTCs are stored when a malfunction is detected in the side squib RH circuit.

Scheme 225

The side squib LH circuit consists of the center airbag sensor and the front seat airbag LH.

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

These DTCs are stored when a malfunction is detected in the side squib LH circuit.

Scheme 226

The curtain shield squib RH 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 curtain shield squib RH circuit.

Scheme 227

The curtain shield squib LH circuit consists of the center airbag sensor and the curtain shield airbag LH.

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

These DTCs are stored when a malfunction is detected in the curtain shield squib LH circuit.

Scheme 228

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.

Scheme 229

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

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

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

Scheme 230

The rear side squib RH circuit consists of the center airbag sensor and the rear seat side airbag RH.

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

These DTCs are stored when a malfunction is detected in the rear side squib RH circuit.

Scheme 231

The rear side squib LH circuit consists of the center airbag sensor and the rear seat side airbag LH.

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

These DTCs are stored when a malfunction is detected in the rear side squib LH circuit.

Scheme 232

The driver side knee airbag squib circuit consists of the center airbag sensor and the driver side knee airbag.

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

These DTCs are stored when a malfunction is detected in the driver side knee airbag squib circuit.

Scheme 233

The front passenger side knee airbag squib circuit consists of the center airbag sensor and the front passenger side knee airbag.

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

These DTCs are stored when a malfunction is detected in the front passenger side knee airbag squib circuit.

Scheme 234

The front pretensioner squib RH circuit consists of the center airbag sensor and the front seat outer belt RH.

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

These DTCs are stored when a malfunction is detected in the front pretensioner squib RH circuit.

Scheme 235

The front pretensioner squib LH circuit consists of the center airbag sensor and the front seat outer belt LH.

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

These DTCs are stored when a malfunction is detected in the front pretensioner squib LH circuit.

Scheme 236

The rear pretensioner squib RH circuit consists of the center airbag sensor and the rear seat outer belt RH.

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

These DTCs are stored when a malfunction is detected in the rear pretensioner squib RH circuit.

Scheme 237

The rear pretensioner squib LH circuit consists of the center airbag sensor and the rear seat outer belt LH.

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

These DTCs are stored when a malfunction is detected in the rear pretensioner squib LH circuit.

Scheme 238

The SRS warning light is located on the combination meter.

When the SRS is normal, the SRS warning light comes on for approximately 6 seconds after the engine switch is turned from off to on (IG), and then goes off automatically.

If there is a malfunction in the SRS, the SRS warning light comes on to inform the driver of a problem.

When terminals TC and CG of the DLC3 are connected, DTCs are output by the blinking of the SRS warning light.

The SRS is equipped with a voltage-increase circuit (DC-DC converter) in the center airbag sensor in case the source voltage drops.

When the battery voltage drops, the voltage-increase circuit (DC-DC converter) functions to increase the voltage of the SRS to normal voltage.

A malfunction in this circuit is not recorded in the center airbag sensor. The SRS warning light automatically goes off when the source voltage returns to normal.

The signal to illuminate the SRS warning light is transmitted from the center airbag sensor to the combination meter through the CAN communication system.

Scheme 239

Refer to "SRS Warning Light Remains ON". Refer to «SRS Warning Light Remains ON».

DTC output mode is set by connecting terminals TC and CG of the DLC3.

DTCs are output by the blinking of the SRS warning light.

HINT

1. When each warning light stays blinking, a ground short in the wiring of terminal TC of the DLC3 or an internal ground short in each ECU is suspected.
2. A DTC output mode signal is transmitted through the CAN communication system to each ECU including the center airbag sensor. Thus, when all systems do not enter DTC output mode, there may be an ECM malfunction.

Scheme 240

See also:
• REMOVAL
• REMOVAL
• PRECAUTION