§571.138 Standard No. 138; Tire pressure
monitoring systems.
S1 Purpose and scope.
This standard specifies performance requirements for tire pressure monitoring
systems (TPMSs)
to warn drivers of significant under-inflation of tires and the resulting
safety problems.
S2 Application. This
standard applies to passenger cars, multipurpose passenger vehicles, trucks,
and buses that have a gross vehicle weight rating of 4,536 kilograms (10,000
pounds) or less, except those vehicles with dual wheels on an axle, according
to the phase-in schedule specified in S7 of this standard.
S3 Definitions. The
following definitions apply to this standard:
Lightly loaded vehicle weight
means unloaded vehicle weight plus the weight of a mass of 180 kg (396 pounds),
including test driver and instrumentation.
Tire pressure monitoring system
means a system that detects when one or more of a vehicle's tires is significantly
under-inflated and illuminates a low tire pressure warning telltale.
Vehicle Placard and Tire inflation
pressure label mean the sources of information for the vehicle
manufacturer's recommended
cold tire inflation pressure pursuant to §571.110 of this Part.
S4 Requirements.
S4.1 General. To the extent provided in S7, each vehicle must be equipped with
a tire
pressure monitoring system that meets the requirements specified in S4 under
the test conditions specified in S5 and the test procedures specified in S6 of
this standard.
S4.2 TPMS detection requirements.
The tire pressure monitoring system must:
(a) Illuminate a low tire pressure warning telltale not more than 20 minutes
after the inflation pressure in one or more of the vehicle's tires, up to a
total of four tires, is equal to or less than either the pressure 25 percent
below the vehicle manufacturer's
recommended cold inflation pressure, or the pressure specified in the 3rd
column of Table 1 of this standard for the corresponding type of tire,
whichever is higher;
(b) Continue to illuminate the low tire pressure warning telltale as long as
the pressure in any of the vehicle's tires is equal to or less than the
pressure specified in S4.2(a), and the ignition
locking system is in the “On” (“Run”) position, whether or not the engine is
running, or until manually reset in accordance with the vehicle manufacturer's
instructions.
S4.3 Low tire pressure warning telltale.
S4.3.1 Each
tire pressure monitoring system must include a low tire pressure warning
telltale that:
(a) Is mounted inside the occupant compartment in front of and in clear view
of the driver;
(b) Is identified by one of the symbols shown for the “Low Tire Pressure” Telltale in Table 1 of Standard No. 101 (49 CFR 571.101); and
(c) Is illuminated under the conditions specified in S4.2.
S4.3.2 In the case of a telltale that identifies which tire(s) is (are)
under-inflated, each tire in the symbol for that telltale must illuminate when
the tire it represents is under-inflated to the extent specified in S4.2.
S4.3.3 (a) Except as provided in paragraph (b) of this section, each low
tire pressure warning telltale must illuminate as a check of lamp function
either when the ignition locking system is activated to the “On” (“Run”)
position when the engine is not running, or when the ignition locking system is
in a position between “On” (“Run”) and “Start” that is designated by the
manufacturer as a check position.
(b) The low tire pressure warning telltale need not illuminate when a
starter interlock is in operation.
S4.4 TPMS malfunction.
(a) The vehicle shall be equipped with a tire pressure monitoring system
that includes a telltale that provides a warning to the driver not more than 20
minutes after the occurrence of a malfunction that affects the generation or
transmission of control or response signals in the vehicle's tire pressure
monitoring system. The vehicle's TPMS malfunction indicator shall meet the requirements
of either S4.4(b)
or S4.4(c).
(b) Dedicated TPMS malfunction
telltale. The vehicle meets the requirements of S4.4(a) when
equipped with a dedicated TPMS
malfunction telltale that:
(b)(1) Is mounted inside the occupant compartment in front of and in clear
view of the driver;
(b)(2) Is identified by the word “TPMS” as described under the “Tire Pressure Monitoring System Malfunction” Telltale in Table 1 of Standard No. 101 (49 CFR 571.101);
(b)(3) Continues to illuminate the TPMS malfunction telltale under the conditions specified in S4.4(a) for as long as the malfunction exists, whenever the ignition locking system is in the “On” (“Run”) position; and
(b)(4)(i)
Except as provided in paragraph (ii), each dedicated TPMS malfunction telltale must be
activated as a check of lamp function either when the ignition locking system
is activated to the “On” (“Run”) position when the engine is not running, or
when the ignition locking system is in a position between “On” (“Run”) and
“Start” that is designated by the manufacturer as a check position.
(b)(4)(ii) The dedicated TPMS
malfunction telltale need not be activated when a starter interlock is in
operation.
(c) Combination low tire pressure/TPMS malfunction
telltale. The vehicle meets the requirements of S4.4(a) when
equipped with a combined Low Tire Pressure/TPMS malfunction telltale that:
(c)(1) Meets the requirements of S4.2 and S4.3; and
(c)(2) Flashes for a period of at least 60 seconds but no longer than 90 seconds upon detection of any condition specified in S4.4(a) after the ignition locking system is activated to the “On” (“Run”) position. After each period of prescribed flashing, the telltale must remain continuously illuminated as long as a malfunction exists and the ignition locking system is in the “On” (“Run”) position. This flashing and illumination sequence must be repeated each time the ignition locking system is placed in the “On” (“Run”) position until the situation causing the malfunction has been corrected. Multiple malfunctions occurring during any ignition cycle may, but are not required to, reinitiate the prescribed flashing sequence.
S4.5 Written instructions.
(a) Beginning on September 1, 2006, the owner's manual in each vehicle certified as complying with S4 must provide an image of the Low Tire Pressure Telltale symbol (and an image of the TPMS Malfunction Telltale warning (“TPMS”), if a dedicated telltale is utilized for this function) with the following statement in English:
Each tire, including the spare (if provided), should be checked monthly when
cold and inflated to the inflation pressure recommended by the vehicle manufacturer on the
vehicle placard or tire inflation pressure label. (If your vehicle has tires of
a different size than the size indicated on the vehicle placard or tire
inflation pressure label, you should determine the proper tire inflation
pressure for those tires.)
As an added safety feature, your vehicle has been equipped with a tire
pressure monitoring system (TPMS)
that illuminates a low tire pressure telltale when one or more of your tires is
significantly under-inflated. Accordingly, when the low tire pressure telltale
illuminates, you should stop and check your tires as soon as possible, and
inflate them to the proper pressure. Driving on a significantly under-inflated
tire causes the tire to overheat and can lead to tire failure. Under-inflation
also reduces fuel efficiency and tire tread life, and may affect the vehicle's
handling and stopping ability.
Please note that the TPMS
is not a substitute for proper tire maintenance, and it is the driver's
responsibility to maintain correct tire pressure, even if under-inflation has
not reached the level to trigger illumination of the TPMS low tire pressure telltale.
[The following paragraph is required for all vehicles certified to the
standard starting on
(b) The owner's manual may include additional information about the time for
the TPMS
telltale(s) to extinguish once the low tire pressure condition or the
malfunction is corrected. It may also include additional information about the
significance of the low tire pressure warning telltale illuminating, a
description of corrective action to be undertaken, whether the tire pressure
monitoring system functions with the vehicle's spare tire (if provided), and
how to use a reset button, if one is provided.
(c) If a vehicle does not come with an owner's manual, the required
information shall be provided in writing to the first purchaser of the vehicle.
S5 Test conditions.
S5.1 Ambient temperature.
The ambient temperature is between 0°C (32°F) and 40°C (104°F).
S5.2 Road test surface.
Compliance testing is conducted on any portion of the
S5.3 Vehicle conditions.
S5.3.1
Test weight.
The vehicle may be tested at any weight between its lightly loaded vehicle
weight and its gross vehicle weight rating (GVWR) without exceeding any of its
gross axle weight ratings.
S5.3.2 Vehicle speed. The
vehicle's TPMS
is calibrated and tested at speeds between 50 km/h (31.1 mph) and 100 km/h
(62.2 mph). For vehicles equipped with cruise control, cruise control is not to
be engaged during testing.
S5.3.3
Rim position.
The vehicle rims may be positioned at any wheel position, consistent with any
related instructions or limitations in the vehicle owner's manual.
S5.3.4
Stationary location.
The vehicle's tires are shaded from direct sun when the vehicle is parked.
S5.3.5 Brake pedal application.
Driving time shall not accumulate during service brake application.
S5.3.6 Range of conditions or test
parameters. Whenever a range of conditions or test parameters is specified
in this standard, the vehicle must meet applicable requirements when tested at
any point within the range.
S5.3.7
Tires. The
vehicle is tested with the tires installed on the vehicle at the time of
initial vehicle sale, excluding the spare tire (if provided). However, the
spare tire may be utilized for TPMS malfunction testing purposes.
S6 Test procedures.
(a) Inflate the vehicle's tires to the cold tire inflation pressure(s)
provided on the vehicle placard or the tire inflation pressure label.
(b) With the vehicle stationary and the ignition locking system in the
“Lock” or “Off” position, activate the ignition locking system to the “On”
(“Run”) position or, where applicable, the appropriate position for the lamp
check. The tire pressure monitoring system must perform a check of lamp
function for the low tire pressure telltale as specified in paragraph S4.3.3 of
this standard. If the vehicle is equipped with a separate TPMS malfunction telltale, the tire
pressure monitoring system also must perform a check of lamp function as
specified in paragraph S4.4(b)(4) of this standard.
(c) If applicable, set or reset the tire pressure monitoring system in
accordance with the instructions in the vehicle owner's manual.
(d) System calibration/learning phase.
(d)(1) Drive the vehicle for up to 15 minutes of cumulative time (not
necessarily continuously) along any portion of the test course.
(d)(2) Reverse direction on the course and drive the vehicle for an
additional period of time for a total cumulative time of 20 minutes (including
the time in S6(d)(1),
and not necessarily continuously).
(e) Stop the vehicle and deflate any combination of one to four tires until the deflated tire(s) is (are) at 7 kPa (1 psi) below the inflation pressure at which the tire pressure monitoring system is required to illuminate the low tire pressure warning telltale.
(f) System detection phase.
(f)(1) Within 5 minutes of reducing the inflation pressure in the tire(s),
drive the vehicle for up to 10-15 minutes of cumulative time (not necessarily
continuously) along any portion of the test course.
(f)(2) Reverse direction on the course and drive the vehicle for an
additional period of time for a total cumulative time of 20 minutes (including
the time in S6(f)(1),
and not necessarily continuously).
(f)(3) The sum of the total cumulative drive time under paragraphs S6(f)(1)
and (2) shall be the lesser of 20 minutes or the time at which the low tire
pressure telltale illuminates.
(f)(4) If the low tire pressure telltale did not illuminate, discontinue the
test.
(g) If the low tire pressure telltale illuminated during the procedure in
paragraph S6(f),
deactivate the ignition locking system to the “Off” or “Lock” position. After a
5-minute period, activate the vehicle's ignition locking system to the “On”
(“Run”) position. The telltale must illuminate and remain illuminated as long
as the ignition locking system is in the “On” (“Run”) position.
(h) Keep the vehicle stationary for a period of up to one hour with the
engine off.
(i)
Inflate all of the vehicle's tires to the same inflation pressure used in
paragraph S6(a).
If the vehicle's tire pressure monitoring system has a manual reset feature,
reset the system in accordance with the instructions specified in the vehicle
owner's manual. Determine whether the telltale has extinguished. If necessary,
drive the vehicle until the telltale has been extinguished.
(j)
The test may be repeated, using the test procedures in paragraphs S6(a)-(b)
and S6(d)-(i),
with any one, two, three, or four of the tires on the vehicle under-inflated.
(k) Simulate one TPMS malfunction by disconnecting the power source to any TPMS component, disconnecting any electrical connection between TPMS components, or installing a tire or wheel on the vehicle that is incompatible with the TPMS. When simulating a TPMS malfunction, the electrical connections for the telltale lamps are not to be disconnected.
(l) TPMS malfunction
detection.
(l)(1) Drive the vehicle for up to 15 minutes of cumulative time (not
necessarily continuously) along any portion of the test course.
(l)(2) Reverse direction on the course and drive the vehicle for an
additional period of time for a total cumulative time of 20 minutes (including
the time in S6(l)(1),
and not necessarily continuously).
(l)(3) The sum of the total cumulative drive time under paragraphs S6(l)(1)
and (2) shall be the lesser of 20 minutes or the time at which the TPMS malfunction
telltale illuminates.
(l)(4) If the TPMS
malfunction indicator did not illuminate in accordance with paragraph S4.4, as
required, discontinue the test.
(m) If the TPMS
malfunction indicator illuminated during the procedure in paragraph S6(l),
deactivate the ignition locking system to the “Off” or “Lock” position. After a
5-minute period, activate the vehicle's ignition locking system to the “On”
(“Run”) position. The TPMS
malfunction indicator must again signal a malfunction and remain illuminated as
long as the ignition locking system is in the “On” (“Run”) position.
(n) Restore the TPMS
to normal operation. If necessary, drive the vehicle until the telltale has extinguished.
(o) The test may be repeated using the test procedures in paragraphs S6(k)-(n), with each such test limited to simulation of a single malfunction.
S7 Phase-in schedule.
S7.1 Vehicles manufactured on or
after
(a) The manufacturer's average annual production of vehicles manufactured on
or after
(b) The manufacturer's production on or after
S7.2 Vehicles manufactured on or
after
(a) The manufacturer's average annual production of vehicles manufactured on
or after
(b) The manufacturer's production on or after
S7.3 Vehicles manufactured on or
after
S7.4 Calculation of complying vehicles.
(a) Carry-Forward Credits. For
purposes of complying with S7.1, a manufacturer may count a vehicle if it is
certified as complying with this standard and is manufactured on or after
(b) For purposes of complying with S7.2, a manufacturer may count a vehicle
if it:
(b)(1)(i)
Is certified as complying with this standard and is manufactured on or after
April 8, 2005, but before September 1, 2007; and
(b)(1)(ii) Is not counted toward compliance with S7.1; or
(b)(2) Is manufactured on or after
(c)
Carry-Backward Credits. At the
vehicle manufacturer's option, for purposes of complying with S7.1, a
manufacturer may count a vehicle it plans to manufacture and to certify as
complying with this standard that will be produced on or after
S7.5 Vehicles produced by more than one
manufacturer.
S7.5.1 For the purpose of calculating average annual production of vehicles
for each manufacturer and the number of vehicles manufactured by each
manufacturer under S7.1 through S7.3, a vehicle produced by more than one
manufacturer must be attributed to a single manufacturer as follows, subject to
S7.5.2:
(a) A vehicle that is imported must be attributed to the importer.
(b) A vehicle manufactured in the
S7.5.2 A vehicle produced by more than one manufacturer must be attributed
to any one of the vehicle's manufacturers specified by an express written
contract, reported to the National Highway Traffic Safety Administration under
49 CFR Part 585, between the manufacturer so specified and the manufacturer to
which the vehicle would otherwise be attributed under S7.5.1.
S7.6 Small volume manufacturers.
Vehicles manufactured by a manufacturer that produces fewer than 5,000 vehicles
for sale in the United States during the period of September 1, 2005 to August
31, 2006, or the period from September 1, 2006 to August 31, 2007, are not
subject to the corresponding requirements of S7.1, S7.2, and S7.4.
S7.7 Final-stage manufacturers and alterers. Vehicles that are
manufactured in two or more stages or that are altered (within the meaning of
49 CFR 567.7) after having previously been certified in accordance with Part
567 of this chapter are not subject to the requirements of S7.1 through S7.4.
Instead, vehicles that are manufactured in two or more stages or that are
altered must comply with this standard beginning on
Table 1.--Low Tire Pressure Warning
Telltale--Minimum Activation Pressure
|
Column 1—tire type |
Column 2—maximum or rated inflation pressure |
Column 3—minimum activation pressure |
||
|
(kPa) |
(psi) |
(lPa) |
(psi) |
|
|
P-metric—Standard Load |
240, |
35, |
140 |
20 |
|
300, or |
44, or |
140 |
20 |
|
|
350 |
51 |
140 |
20 |
|
|
P-metric—Extra Load |
280 or |
41 or |
160 |
23 |
|
340 |
49 |
160 |
23 |
|
|
Load Range C |
350 |
51 |
200 |
29 |
|
|
450 |
65 |
240 |
35 |
|
Load Range E |
550 |
80 |
240 |
35 |
[68 FR 65409,