Supplemental Restraint System: Overview Mitsubishi Eclipse IV рестайлинг

GENERAL DESCRIPTION

Note. In this service information , the part names are changed from the names in owner's manual into the following names. Driver's seat position sensor --> Seat slide sensor Passenger's seat weight sensor --> Occupant classification sensor Seat belt buckle switch --> Seat belt switch Passenger air bag off indicator --> Passenger air bag OFF indicator light Front passenger seat belt warning light --> Passenger seat belt warning light

The SRS is designed to supplement the front seat belts. It reduces injury to the driver(s) and the front passenger(s) by deploying air bag(s) in case of a head-on collision.

The SRS front air bags form an advanced air bag system together with sensors at the vehicle and sensors attached to the front seats.

Side-airbag systems in the front seats are activated when side impacts exceed criteria to protect the occupants' upper bodies.

The curtain air bag systems are activated when side impacts applied to the vehicle exceed criteria, to protect the heads of the occupants in the front seats.

The seat belts with pre-tensioner work simultaneously with the SRS. The seat belt incorporating the pre-tensioner automatically winds the seat belt upon front impact to reduce forward shifting of the driver's and passenger's. The seat belt use status controls the activation and deactivation of the pre-tensioner.

The SRS consists of six air bag modules, SRS air bag control unit (SRS-ECU), two front impact sensors, two side impact sensors, SRS warning light, passenger air bag OFF indicator light, passenger seat belt warning light, clock spring, seat belt pre-tensioner, seat belt switch, seat slide sensor, occupant classification sensor and occupant classification-ECU. Air bag modules are located in the center of the steering wheel and above the glove box. Side-airbags are located inside the front seatback assemblies. The curtain air bag module consists of an air bag, an inflator, and the fixing gear relating to those parts, and is installed in the roof side sections (from the driver's and the passenger's front pillars to the rear pillars). Each air bag consists of a folded air bag and an inflator unit. The SRS-ECU placed on the forefront of the floor monitors the system and has a front air bag safing G-sensor, front air bag analog G-sensor and a side-airbag safing G-sensor. The front impact sensor is assembled in the radiator support panel to monitor impact in case of front impact. The side impact sensors inside the center pillars monitor the shock incurred by the sides of the vehicle. The SRS warning light on the combination meter indicates the operational status of the SRS. The clock spring is installed in the steering column. The seat belt pre-tensioner is built into the driver's and passenger's front seat belt retractor. The seat slide sensor is installed at the seat adjuster section of the driver seat in order to detect the driver seat slide position. The occupant classification sensor is installed underneath a rail of the passenger seat to detect the load on the seat. The passenger air bag OFF indicator light is installed to the lower left of the multi-center display, and illuminates when the passenger seat air bag is inactive. The passenger seat belt warning light is installed to the lower right of the multi-center display, and illuminates when the passenger is not wearing the seat belt. The seat belt switch detects whether the seat belt is used.

Only authorized service personnel should do work on or around the SRS components. Those service personnel should read this service information carefully before starting any such work.

INTRODUCTION TO DIAGNOSIS

The SRS system is controlled by the SRS-ECU. The SRS-ECU judges how severe a collision is by detecting signals from the left and right front impact sensors and side impact sensors, front air bag analog G-sensor and front air bag safing G-sensor and side-airbag safing G-sensor. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the safing G-sensor is on, the SRS air bag will inflate. (The passenger's air bag may not inflate according to the occupant detection data from the occupant classification-ECU). The SRS warning light in the combination meter alerts a malfunction of the SRS system. If the following symptoms occur even when the vehicle has not been in a collision, there may be a malfunction in the SRS system.

1. The SRS warning light does not go off within approximately seven seconds after the ignition switch has been turned to the "ON" position.
2. The SRS warning light does not illuminate when the ignition switch is turned to the "ON" position.

Refer to Post-collision Diagnosis when inspecting and servicing a vehicle that has been in a collision (Refer to POST-COLLISION DIAGNOSIS ).

CIRCUIT OPERATION

1. The SRS-ECU judges how severe a collision is by detecting signals from the front impact sensors and the front air bag analog G-sensor. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the front air bag safing G-sensor is on, the SRS air bag will inflate.
2. The ignition signal is input to the air bag module via the clock spring to inflate the air bag.

1. The SRS-ECU judges how severe a collision is by detecting signals from the front impact sensors and the front air bag analog G-sensor. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the front air bag safing G-sensor is on, the SRS air bag will inflate.
2. The ignition signal is input to the air bag module via the clock spring to inflate the air bag.

1. The SRS-ECU judges how severe a collision is by detecting signals from the front impact sensors and the front air bag analog G-sensor. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the front air bag safing G-sensor is on, the SRS air bag will inflate.
2. The ignition signal is sent to the air bag module via the clock spring to inflate the air bag.

1. The SRS-ECU judges how severe a collision is by detecting signals from the front impact sensors and the front air bag analog G-sensor. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the front air bag safing G-sensor is on, the SRS air bag will inflate.
2. The ignition signal is input to the air bag module via the clock spring to inflate the air bag.

The front impact sensor includes an analog G-sensor and CPU, etc. The CPU monitors the analog G-sensor output signal. If the CPU judges that the front air bags should be deployed, it sends a fire signal to the SRS-ECU to deploy the front air bags. In addition, the CPU diagnoses the internal components of the front impact sensor. If a malfunction occurs, it requests the SRS-ECU to set a diagnostic trouble code.

The front impact sensor includes an analog G-sensor and CPU, etc. The CPU monitors the analog G-sensor output signal. If the CPU judges that the front air bags should be deployed, it sends a fire signal to the SRS-ECU to deploy the front air bags. In addition, the CPU diagnoses the internal components of the front impact sensor. If a malfunction occurs, it requests the SRS-ECU to set a diagnostic trouble code.

1. The SRS-ECU judges how severe a collision is by detecting signals from the front impact sensors and the front air bag analog G-sensor. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the front air bag safing G-sensor is on, the SRS air bag will inflate.
2. The ignition signal is input to the air bag module via the clock spring to inflate the air bag.

1. The SRS-ECU judges how severe a collision is by detecting signals from the front impact sensors and the front air bag analog G-sensor. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the front air bag safing G-sensor is on, the SRS air bag will inflate.
2. The ignition signal is input to the air bag module via the clock spring to inflate the air bag.

1. The SRS-ECU judges how severe a collision is by detecting signals from the front impact sensors and the front air bag analog G-sensor. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the front air bag safing G-sensor is on, the SRS air bag will inflate.
2. The ignition signal is input to the air bag module via the clock spring to inflate the air bag.

1. The SRS-ECU judges how severe a collision is by detecting signals from the front impact sensors and the front air bag analog G-sensor. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the front air bag safing G-sensor is on, the SRS air bag will inflate.
2. The ignition signal is input to the air bag module via the clock spring to inflate the air bag.

The front impact sensor includes an analog G-sensor and CPU, etc. The CPU monitors the analog G-sensor output signal. If the CPU judges that the front air bags should be deployed, it sends a fire signal to the SRS-ECU to deploy the front air bags. In addition, the CPU diagnoses the internal components of the front impact sensor. If a malfunction occurs, it requests the SRS-ECU to set a diagnostic trouble code.

The front impact sensor includes an analog G-sensor and CPU, etc. The CPU monitors the analog G-sensor output signal. If the CPU judges that the front air bags should be deployed, it sends a fire signal to the SRS-ECU to deploy the front air bags. In addition, the CPU diagnoses the internal components of the front impact sensor. If a malfunction occurs, it requests the SRS-ECU to set a diagnostic trouble code.

1. The SRS-ECU judges how severe a collision is by detecting signals from the left and right side impact sensors. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the side-airbag safing G-sensor is on, the SRS side-airbag will inflate.
2. The ignition signal is input to the side-airbag module to inflate the side-airbag.

1. The SRS-ECU judges how severe a collision is by detecting signals from the left and right side impact sensors. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the side-airbag safing G-sensor is on, the SRS side-airbag will inflate.
2. The ignition signal is input to the side-airbag module to inflate the side-airbag.

1. The SRS-ECU judges how severe a collision is by detecting signals from the left and right side impact sensors. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the side-airbag safing G-sensor is on, the SRS side-airbag will inflate.
2. The ignition signal is input to the side-airbag module to inflate the side-airbag.

1. The SRS-ECU judges how severe a collision is by detecting signals from the left and right side impact sensors. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the side-airbag safing G-sensor is on, the SRS side-airbag will inflate.
2. The ignition signal is input to the side-airbag module to inflate the side-airbag.

The side impact sensor includes an analog G-sensor and CPU, etc. The CPU monitors the analog G-sensor output signal. If the CPU judges that the side-airbags should be deployed, it sends a fire signal to the SRS-ECU to deploy the side-airbags. In addition, the CPU diagnoses the internal components of the side impact sensor. If a malfunction occurs, it requests the SRS-ECU to set a diagnostic trouble code.

The side impact sensor includes an analog G-sensor and CPU, etc. The CPU monitors the analog G-sensor output signal. If the CPU judges that the side-airbags should be deployed, it sends a fire signal to the SRS-ECU to deploy the side-airbags. In addition, the CPU diagnoses the internal components of the side impact sensor. If a malfunction occurs, it requests the SRS-ECU to set a diagnostic trouble code.

1. The SRS-ECU judges how severe a collision is by detecting signals from the left and right side impact sensors. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the side-airbag safing G-sensor is on, the SRS side-airbag will inflate.
2. The ignition signal is input to the side-airbag module to inflate the side-airbag.

1. The SRS-ECU judges how severe a collision is by detecting signals from the left and right side impact sensors. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the side-airbag safing G-sensor is on, the SRS side-airbag will inflate.
2. The ignition signal is input to the side-airbag module to inflate the side-airbag.

1. The SRS-ECU judges how severe a collision is by detecting signals from the left and right side impact sensors. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the side-airbag safing G-sensor is on, the SRS side-airbag will inflate.
2. The ignition signal is input to the side-airbag module to inflate the side-airbag.

1. The SRS-ECU judges how severe a collision is by detecting signals from the left and right side impact sensors. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the side-airbag safing G-sensor is on, the SRS side-airbag will inflate.
2. The ignition signal is input to the side-airbag module to inflate the side-airbag.

The side impact sensor includes an analog G-sensor and CPU, etc. The CPU monitors the analog G-sensor output signal. If the CPU judges that the side-airbags should be deployed, it sends a fire signal to the SRS-ECU to deploy the side-airbags. In addition, the CPU diagnoses the internal components of the side impact sensor. If a malfunction occurs, it requests the SRS-ECU to set a diagnostic trouble code.

The side impact sensor includes an analog G-sensor and CPU, etc. The CPU monitors the analog G-sensor output signal. If the CPU judges that the side-airbags should be deployed, it sends a fire signal to the SRS-ECU to deploy the side-airbags. In addition, the CPU diagnoses the internal components of the side impact sensor. If a malfunction occurs, it requests the SRS-ECU to set a diagnostic trouble code.

1. The SRS-ECU judges how severe a collision is by detecting signals from the left and right side impact sensors. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the side-airbag safing G-sensor is on, the SRS side-airbag will inflate.
2. The ignition signal is input to the curtain air bag module (RH) to inflate the curtain air bag.

1. The SRS-ECU judges how severe a collision is by detecting signals from the left and right side impact sensors. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the side-airbag safing G-sensor is on, the SRS side-airbag will inflate.
2. The ignition signal is input to the curtain air bag module to inflate the curtain air bag.

1. The SRS-ECU judges how severe a collision is by detecting signals from the left and right side impact sensors. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the side-airbag safing G-sensor is on, the SRS side-airbag will inflate.
2. The ignition signal is input to the curtain air bag module (RH) to inflate the curtain air bag.

1. The SRS-ECU judges how severe a collision is by detecting signals from the left and right side impact sensors. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the side-airbag safing G-sensor is on, the SRS side-airbag will inflate.
2. The ignition signal is input to the curtain air bag module to inflate the curtain air bag.

1. The SRS-ECU judges how severe a collision is by detecting signals from the left and right side impact sensors. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the side-airbag safing G-sensor is on, the SRS side-airbag will inflate.
2. The ignition signal is input to the curtain air bag module (LH) to inflate the curtain air bag.

1. The SRS-ECU judges how severe a collision is by detecting signals from the left and right side impact sensors. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the side-airbag safing G-sensor is on, the SRS side-airbag will inflate.
2. The ignition signal is input to the curtain air bag module (LH) to inflate the curtain air bag.

1. The SRS-ECU judges how severe a collision is by detecting signals from the left and right side impact sensors. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the side-airbag safing G-sensor is on, the SRS side-airbag will inflate.
2. The ignition signal is input to the curtain air bag module (LH) to inflate the curtain air bag.

1. The SRS-ECU judges how severe a collision is by detecting signals from the left and right side impact sensors. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the side-airbag safing G-sensor is on, the SRS side-airbag will inflate.
2. The ignition signal is input to the curtain air bag module (LH) to inflate the curtain air bag.

The SRS-ECU judges how severe a collision is by detecting signals from the front impact sensors and the front air bag analog G-sensor. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the front air bag safing G-sensor is on, the pre-tensioner will deploy.

The SRS-ECU judges how severe a collision is by detecting signals from the front impact sensors and the front air bag analog G-sensor. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the front air bag safing G-sensor is on, the pre-tensioner will deploy.

The SRS-ECU judges how severe a collision is by detecting signals from the front impact sensors and the front air bag analog G-sensor. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the front air bag safing G-sensor is on, the pre-tensioner will deploy.

The SRS-ECU judges how severe a collision is by detecting signals from the front impact sensors and the front air bag analog G-sensor. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the front air bag safing G-sensor is on, the pre-tensioner will deploy.

The SRS-ECU judges how severe a collision is by detecting signals from the front impact sensors and the front air bag analog G-sensor. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the front air bag safing G-sensor is on, the pre-tensioner will deploy.

The SRS-ECU judges how severe a collision is by detecting signals from the front impact sensors and the front air bag analog G-sensor. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the front air bag safing G-sensor is on, the pre-tensioner will deploy.

The SRS-ECU judges how severe a collision is by detecting signals from the front impact sensors and the front air bag analog G-sensor. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the front air bag safing G-sensor is on, the pre-tensioner will deploy.

The SRS-ECU judges how severe a collision is by detecting signals from the front impact sensors and the front air bag analog G-sensor. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the front air bag safing G-sensor is on, the pre-tensioner will deploy.

1. The SRS-ECU is powered from the ignition switch (IG1).
2. The SRS-ECU power is supplied from two circuits. Even if one circuit is shut off, the air bag can inflate.

1. Power for the passenger seat belt warning light is supplied from the ignition switch (IG1).
2. The passenger seat belt warning light illuminates when the ignition switch is turned to the "ON" position and goes out after approximately seven seconds if there is not a malfunction in the SRS system.

1. Power for the passenger seat belt warning light is supplied from the ignition switch (IG1).
2. The passenger seat belt warning light illuminates when the ignition switch is turned to the "ON" position and goes out after approximately seven seconds if there is not a malfunction in the SRS system.
3. If a failure occurs in the system, the SRS-ECU will stop sending that SRS warning light "OFF" signal, thus causing the combination meter to illuminate the SRS warning light.
4. The SRS warning light "OFF" signal is not sent to the combination meter in the cases below, either. Therefore, the combination meter will illuminate the SRS warning light.
5. The SRS-ECU connector is disconnected.
6. The SRS-ECU is not working normally due to a failure in its power supply lines.
7. The wiring harness between the passenger seat belt warning light and the SRS-ECU is broken.

1. Power for the passenger seat belt warning light is supplied from the ignition switch (IG1).
2. The passenger seat belt warning light illuminates when the ignition switch is turned to the "ON" position and goes out after approximately seven seconds if there is not a malfunction in the SRS system.
3. If a failure occurs in the system, the SRS-ECU will stop sending that SRS warning light "OFF" signal, thus causing the combination meter to illuminate the SRS warning light.
4. The SRS warning light "OFF" signal is not sent to the combination meter in the cases below, either. Therefore, the combination meter will illuminate the SRS warning light. The SRS-ECU connector is disconnected.
5. The SRS-ECU is not working normally due to a failure in its power supply lines.
6. The wiring harness between the passenger seat belt warning light and the SRS-ECU is broken.

1. Power for the passenger air bag OFF indicator light is supplied from the ignition switch (IG1).
2. The passenger air bag OFF indicator light illuminates when the ignition switch is turned to the "ON" position and goes out after approximately seven seconds if there is not a malfunction in the SRS system.

1. Power for the passenger air bag OFF indicator light is supplied from the ignition switch (IG1).
2. The passenger air bag OFF indicator light illuminates when the ignition switch is turned to the "ON" position and goes out after approximately seven seconds if there is not a malfunction in the SRS system.
3. If a failure occurs in the system, the SRS-ECU will stop sending that SRS warning light "OFF" signal, thus causing the combination meter to illuminate the SRS warning light.
4. The SRS warning light "OFF" signal is not sent to the combination meter in the cases below, either. Therefore, the combination meter will illuminate the SRS warning light.
5. The SRS-ECU connector is disconnected.
6. The SRS-ECU is not working normally due to a failure in its power supply lines.
7. The wiring harness between the passenger air bag OFF indicator light and the SRS-ECU is broken.

1. Power for the passenger air bag OFF indicator light is supplied from the ignition switch (IG1).
2. The passenger air bag OFF indicator light illuminates when the ignition switch is turned to the "ON" position and goes out after approximately seven seconds if there is not a malfunction in the SRS system.
3. If a failure occurs in the system, the SRS-ECU will stop sending that SRS warning light "OFF" signal, thus causing the combination meter to illuminate the SRS warning light.
4. The SRS warning light "OFF" signal is not sent to the combination meter in the cases below, either. Therefore, the combination meter will illuminate the SRS warning light.
5. The SRS-ECU connector is disconnected.
6. The SRS-ECU is not working normally due to a failure in its power supply lines.
7. The wiring harness between the passenger air bag OFF indicator light and the SRS-ECU is broken.

1. The seat slide sensor sets the current value Hi or Low determined by the seat position.
2. The SRS-ECU determines the seat position according to the current value from the seat slide sensor.

1. The seat slide sensor sets the current value Hi or Low determined by the seat position.
2. The SRS-ECU determines the seat position according to the current value from the seat slide sensor.

1. The seat slide sensor sets the current value Hi or Low determined by the seat position.
2. The SRS-ECU determines the seat position according to the current value from the seat slide sensor.

The SRS-ECU determines whether the seat belt is fastened or not according to the connection location of the seat belt switch in the seat buckle.

The SRS-ECU determines whether the seat belt is fastened or not according to the connection location of the seat belt switch in the seat buckle.

The load data from the occupant classification sensor is classified with the occupant classification-ECU, and its classified information is send to SRS-ECU. The SRS-ECU determines the air bag deployment based on this classified information, and controls the power supply circuit to the inflator.

TECHNICAL DESCRIPTION (COMMENT)

The wiring harness wire or connectors may have loose, corroded, or damage terminals, or terminals pushed back in the connector, or the SRS-ECU may be defective.

The wiring harness wire or connectors may have loose, corroded, or damage terminals, or terminals pushed back in the connector, or the SRS-ECU may be defective.

If the scan tool (MUT-III Sub Assembly) can not communicate with the SRS system, the CAN bus lines may be defective. If the SRS system does not work, the SRS-ECU or its power supply circuit may be defective.

1. The SRS-ECU is energized by the ignition switch (IG1) through multipurpose fuse 3 and the SRS-ECU terminal 23 and multipurpose fuse 2 and the SRS-ECU terminal 24.
2. If the power supply to the SRS-ECU has failed, scan tool (MUT-III Sub Assembly) will not be able to communicate with it.

1. The SRS-ECU sends the SRS warning light signal to the combination meter via the CAN communication.
2. This may be caused by faults in the CAN bus line, the combination meter or the SRS-ECU.