Interpretation ID: nht91-5.42

DATE: September 9, 1991

FROM: None (Confidential)

TO: Paul Jackson Rice -- Office of Chief Counsel, NHTSA

TITLE: Re Request for Interpretation-FMVSS 101 "Controls and Displays and FMVSS 208, "Occupant Crash Protection"

ATTACHMT: Attached to letter dated 11-27-91 from Paul Jackson Rice (A38; Std. 208; Std. 101)

TEXT:

A major automobile manufacturer (hereafter referred to as "The Company") is seeking an interpretation relating to the applicability of a seat belt pretensioner system indicator display with respect to the requirements of FMVSS No. 101; "Controls and Displays" FMVSS No.208; "Occupant Crash Protection".

The Company is planning to incorporate a seat belt "pretensioning" system for active seat belt systems for the front outboard seating positions in some of its future models. The pretensioner system is a device that is designed to retract the belt webbing into the retractor when the vehicle experiences certain frontal area impacts. It is The Company's intention to provide an on board diagnostic system including a malfunction display that will allow the vehicle operator to assess the functional status of the seat belt pretensioner system.

The Company has proposed three alternatives to provide a visual display to illustrate the operational status for the seat belt pretensioner system Those proposals are set forth below.

Proposal #1

The Company proposes to utilize the existing seat belt telltale display field location. Presently, the seat belt telltale illuminates for a period of six seconds following ignition "key on", regardless of whether the seat belt is fastened prior to or following ignition actuation and, in conjunction with a six second audible warning accomplished by either chime or buzzer, signals the occupant to fasten the lap belt webbing of the seat belt. In the event of a pretensioner system failure, a five second period of lamp non-illumination will follow the "fasten belt message, followed by a one second illumination /0.5 second non-illumination cycle which will continue until the ignition key in the lock cylinder is moved to the "off" position. If there is no malfunction in pretensioner system, the only message displayed in the seat belt telltale field will be the "fasten seat belt" message.

Case I - No malfunction in the seat belt pretensioner system

(Text and graphics omitted)

Case II - Malfunction in the seat belt pretensioner system

(Text and graphics omitted)

Seat Belt Telltale Illumination Schematic For Proposal # 1

Proposal # 7

The second proposal also involves combining the "fasten belt" message and the "pretensioner malfunction", thus creating a condition of "non-discrete" messages for cases where a malfunction in the pretensioner system occurs. In the case of no pretensioner malfunction, two conditions exist: one in which the seat belt is fastened prior to ignition on, and one in which the seat belt is fastened following ignition, In the case where the seat belt is fastened prior to ignition, the fasten belt message will illuminate for seven seconds and then be extinguished. In the case where the ignition is activated prior to belt fastening, the "fasten belt" message is displayed until the belt is fastened. The Company believes that this complies with S4.5.3.3 of FMVSS 208.

Case IA - No malfunction in the pretensioner system. Belt fastened prior to ignition on.

(Text and graphics omitted)

Case IB - No malfunction in the pretensioner system. Belt fastened after ignition on.

(Text and graphics omitted)

Seat Belt Telltale Illumination Schematic For Proposal # 2

Proposal # 2 (Continued)

In the case of a pretensioner system malfunction, two conditions will also exist: one in which the belts are fastened after the ignition is activated. In the case where the belts are fastened prior to ignition, the display will illuminate continuously for a seven second period, followed by a non-illuminated period that will last from zero to 28 seconds. A pretensioner system diagnostic period will begin with ignition key on and will be completed within a seven to 35 second time period Following the diagnostic period, the malfunction in the pretensioner will be identified by a 0.5 on / 0,5 off illumination cycle. In the case where the belts are fastened after ignition, a 7 to 35 second illuminated period of diagnostics will occur, followed by a cycle that includes a 0.5 second period of non-illumination, 0.5 period of illumination, 0.5 second period of non-illumination, and a three second period of illumination. This cycle will continue until the seat belt is fastened, or the ignition is turned to the "key-off" position.

Case IIA - Malfunction in the pretensioner system. Belt fastened prior to ignition.

(Text and graphics omitted)

Case IIB - Malfunction in the pretensioner system. Belt fastened after ignition.

Seat Belt Telltale Illumination Schematic For Proposal # 2

Proposal # 3

The third proposal involves the use of the Supplemental Restraint System (SRS) telltale field that is required under the provisions set forth in FMVSS No. 208, Section 4.5.2, "Readiness Indicator" for devices that deploy upon impact. If there is no malfunction in the pretensioner system and/or the air bag system, the SRS telltale will illuminate for 7 seconds and then extinguish. In the event of a pretensioner system malfunction, the SRS telltale will illuminate for seven seconds, experience a non-illuminated zero to 28 second diagnostic assessment period, and then provide a malfunction message by completing a 0.5 second on / 0.5 second off illumination pattern that will be defeated by moving the ignition key to the "off" position. It should be noted that, in the event of an air bag malfunction, the SRS telltale will also provide the identical message, which will not be distinguishable from a malfunction message for the pretensioner system by the customer. However, the malfunction message will be distinguishable to a trained service technician using diagnostic tools.

Case I - No malfunction in the air bag and / or pretensioner system

(Text and graphics omitted)

Case II - Malfunction in the air bag and / or pretensioner system

(Text and graphics omitted)

SRS Readiness Indicator Illumination Schematic for proposal # 3

The Company requests that the NHTSA Office of Chief Counsel provide interpretation regarding the proposals as follows:

Proposals # 1 and # 2

1) Does Proposal # 1 and / or Proposal # 2 comply with the requirements of FMVSS 101, S5.4 for use of common space to display messages?

2) Does Proposal # 1 comply with FMVSS 208, 57.3?

3) Does Proposal # 2 comply with FMVSS 208, S4.5.3.3(b)?

4) Is the pretensioner system malfunction message applicable to the "Readiness Indicator" requirements of FMVSS 208, S4.5.2?

5) If the seat belt pretensioner malfunction is interpreted as a "Readiness Indicator" as defined in FMVSS 208, S4.5.2 as a device that deploys upon impact, can its telltale be displayed in a common telltale display field that is required pursuant to FMVSS 101?

Proposal # 3

1) Is it necessary to provide two distinctive messages to indicate an air bag system malfunction and a seat belt pretensioner system malfunction, or is the general message indicating a malfunction in the air bag system and / or belt pretensioner system acceptable?

2) If the pretensioner system malfunction message is interpreted to be a readiness indicator, is it subject to FMVSS 101, S5.4.2. (Are readiness indicators also subject to FMVSS 101 requirements.)?

3) If the seat belt pretensioner malfunction is interpreted as a "Readiness Indicator" as defined as a device that deploys upon impact, can its telltale be displayed in a common telltale display field that is required pursuant to FMVSS 101?

General

Will The Company be required to furnish a separate display field for the pretensioner system operational status if all three proposals are interpreted as not complying with FMVSS 101 or FMVSS 208?