P0270
2004 ELANTRA SUPPLEMENTAL RESTRAINT SYSTEMDESCRIPTION: This bulletin provides general information for the Supplemental Restraint System (SRS) that is installed in 2004 MY Elantra vehicles produced beginning in July 2003.
The dual-stage front airbags provide two levels of inflation. A first stage inflation is provided for moderate impacts, while a second stage inflation is provided for more severe impacts.
In order to determine whether a first or second stage deployment should occur, the SRS uses several sensors to obtain information regarding the impact speed, seat belt usage and front seat position.
See the 2004 Elantra Shop Manual Restraints Section and the Owner's Manual for further information about supplemental restraint systems.
SRS COMPONENT LOCATIONS:
SRS COMPONENTS LISTING:
Driver Airbag (DAB):
The driver airbag is a dual output type. Airbag inflation is determined by the impact speed, seat belt usage and driver seat position.
Since the dual-stage front airbag system has two (2) circuits, the DAB has two (2) connectors for the circuits. The two connectors are of a different style and are not interchangeable.
Passenger Airbag (PAB):
The passenger airbag is also a dual output type. Airbag inflation is determined by the impact speed, seat belt usage and front passenger seat position.
Although the PAB is a dual-stage airbag (like the DAB), it has one connector (4 pins) for the two circuits.
The PAB connector is located behind the dash panel, directly above the HVAC blower motor.
Occupant Classification System (OCS):
The Occupant Classification System detects the presence of a passenger in the front passenger's seat and will turn off the front passenger's airbag under certain conditions. The driver's airbag and the driver's side impact airbag are not affected by the OCS.
The OCS is designed to detect the presence of a properly seated occupant (sitting upright with the seat in an upright position, centered on the seat cushion, with legs comfortably extended) and determine if the passenger's airbag and the passenger's side impact airbag should be enabled (may inflate) or not.
Located at the center of the instrument panel, the "PASSENGER AIRBAG OFF" warning lamp provides the passenger airbag status. If the front passenger seat is unoccupied or occupied by someone lighter than approximately 55 pounds (24.9 kg), the indicator "PASSENGER AIRBAG OFF" will be displayed and the front passenger's airbag and side impact airbag will be turned off and will not deploy in frontal or side impacts.
The OCS's force sensor resistor (FSR) cells are located in the front passenger seat. The FSR's resistance values decrease with increasing weight. When a person sits in the passenger seat, the resistance in each FSR cell will decrease relative to the load. When a predetermined number of these cells have been detected, the PAB circuitry is activated and the "PASSENGER AIRBAG OFF" lamp is turned off.
Weight Sensing Detector:
Seat Track Position Sensor (STPS):
The Seat Track Position Sensor is located on the inside seat rail of both front seats. The STPS resistance changes depending on its location relative to a vane mounted on the seat rail. When the STPS is positioned over the vane (9 latching positions or more rearward of the forward-most position), its resistance is approximately 900 ohms. When it is positioned off of the vane (within 8 latching positions from the forward most position), the sensor's resistance is approximately 300 ohms. (The STPS resistance values are measured without requiring power to the circuit).
In the event of a frontal impact severe enough to deploy the airbags, if one of the front seats is placed within 8 latching positions from the forward-most position (STPS off of the vane), only the first stage circuit will be activated for that airbag. If the front seat is placed 9 latching positions or more rearward of the forward-most position (STPS over the vane), then the SRS Control Module will deploy the bag with either the first or second circuit (depending on seat belt usage and the severity of the impact).
If an STPS condition prevents the SRSCM from determining the position of the seat, a Seat Track Sensor Fault Code is generated and the SRS warning light will illuminate until erased from the SRSCM memory by using a Hi-Scan Pro (the fault code will remain even if the condition has been corrected).
Front Impact Sensor (FIS):
The front impact sensor is mounted under the radiator support panel. The FIS aids in the airbag deployment decision.
Side Impact Airbag (SAB):
The side impact airbags (installed in both driver and passenger front seats) are the single output type. Side airbag equipped vehicles have "SRS AIRBAG" imprinted on the side of the front seats. The two satellite sensors are located at the bottom of the B-pillar, behind the seat belt pretensioner assembly.
NOTE: Any modification(s) of the seats may prevent proper operation of the side impact airbags when they are intended to deploy in a collision and can result in serious injury or death. See TSB# 01-90-012 ("Side Impact Airbags") for more details.
SPECIAL SERVICE TOOL (SST) FOR DUAL-STAGE AIRBAG:
See 2004 Elantra Shop Manual, Restraints Section, for complete dual stage airbag SST information.
SSTs are available through SPX/Kent-Moore at 1-800-345-2233.
CAUTION: Review the safety rules noted in the shop manual before working on vehicles equipped with an airbag system.
DISPOSAL INSTRUCTIONS FOR DUAL-STAGE AIRBAGS:
In a moderate-severity impact requiring deployment of only the first stage of the dualstage airbag, after the first stage of the dual-stage airbag has been deployed, the second stage will be deployed by the SRSCM after the collision event has been completed. Therefore, the airbag second stage does not need to be deployed intentionally for disposal after deployment of the first stage.
In a severe impact, both stages are deployed at the same time.
When scrapping a car or intentionally deploying airbag modules that are to be replaced, deploy each stage individually.