Interpretation ID: Alliance.1

Robert Strassburger, Vice President
Vehicle Safety & Harmonization
Alliance of Automobile Manufacturers
1401 Eye Street, NW, Suite 900
Washington, DC20005-6562

Dear Mr. Strassburger:

This acknowledges receipt of your October 24, 2005, letter regarding our September 7, 2005, final rule responding to petitions for reconsideration under Federal Motor Vehicle Safety Standard (FMVSS) No. 138, Tire Pressure Monitoring Systems (TPMS)(70 FR 53079). Specifically, your letter raised an issue with paragraph S4.4(c)(2) of the standard, which sets requirements for flashing a combined low tire pressure/TPMS malfunction telltale for a period of 60-90 seconds to indicate to the driver when one or more malfunctions in the TPMS have occurred. The Alliance believes that this provision of the standard, as explained in the final rule, is design restrictive to the extent that the flashing sequence for a combined TPMS telltale is permitted only once per ignition cycle, regardless of the number of TPMS malfunctions encountered. Your letter also, argued that there is not a safety need to restrict the combined TPMS telltale to a single flashing sequence in the rare event of multiple TPMS malfunctions.

According to the Alliance, many current TPMSs have design architectures that automatically send a TPMS malfunction alert each time a new malfunction is detected, and you suggested that for manufacturers using such systems, a redesign would not be practicable before the September 1, 2007, compliance date for the TPMS malfunction indicator requirement. Consequently, your letter requested that the agency permit, but not require, vehicle manufacturers to install TPMSs with combined telltales that reinitiate the prescribed flashing sequence upon detection of subsequent TPMS malfunctions. Your letter sought this result either through a letter of interpretation of S4.4(c)(2), or alternatively, you asked that your letter be treated as a petition for reconsideration of the September 7, 2005, final rule.

Given the language of the standard and the preambles generally clear explanation of the agencys expectations regarding the requirements of S4.4(c)(2), we do not believe that the issue you have raised is amenable to a response via a letter of interpretation. Accordingly, we have decided to treat your letter as a petition for reconsideration of the final rule, and after careful consideration of the issue you have raised, we will respond accordingly.

If you have further questions, please feel free to contact Mr. Eric Stas of my staff at (202) 366-2992.

Sincerely,

Stephen P. Wood
Acting Chief Counsel

cc: Docket No. NHTSA-2005-22251
ref:138
d.12/21/05