Summary of the NHTSA TPM Final Ruling
May 30, 2002
For full details of the Department of Transportation NHTSA Federal Motor Vehicle Safety Standard on Tire Pressure Monitoring go to website www.nhtsa.dot.gov. (Warning ref file sizes). The key points of the ruling are set out below:
- The ruling applies to passenger cars, trucks, multipurpose vehicles, buses with GVWR <=10,000 lb, except dual wheels on an axle ("dualie"). It also applies to incomplete, multi-stage build vehicles (i.e. recreational vehicles, conversion vans, etc. in the weight category) The ruling does not apply to motorcycles, trailers, low-speed vehicles, medium or heavy duty vehicles.
- Under-inflation is based on the vehicle manufacturer's recommended cold inflation pressure.
- The final rule is a two part rule
- Short term applies to Nov 1, 2003 through Oct 31, 2006.
- Allows 2 compliance options
- 25% under-inflation warning when any one or more tires, up to 4 tires, are under inflated; and
- 30% under-inflation warning when any single tire is under-inflated. (1 tire warning)
- There is minimum level of pressure defined in Table 1 of the ruling. For P-metric standard load; maximum inflated
pressure of 35/44/51 psi, minimum inflation warning level is 20 psi. This applies to both the 25% and 30% option.
- Long term portion will be issued by March 1, 2005
- Will establish performance requirements effective Nov 1, 2006.
- Anticipate requirements to specify 25% under-inflation warning when any one or more tires, up to 4 tires, are under inflated.**
- Requirements will be based on data and analysis collected during the two year phase in.
- Phase in period
- 10% Nov 1, 2003 - Oct 31, 2004
- 35% Nov 1, 2004 - Oct 31, 2005
- 65% Nov 1, 2005 - Oct 31 2006
- 100% Nov 1, 2006
- Carry-forward credits during phase in period (Nov 1m 2003-Oct 31, 2006) for vehicles using 25% under-inflation warning when any one or more tires, up to 4 tires, are under inflated; but not for 30% system.
- Compatible with
- All replacement or optional tires recommended for use by vehicle manufacturer for vehicle.
- Does not include replacement rims.
- Not required on 'mini-spare' or non-matching full size spare or when this spare is in use.
- Temperature compensation not addressed presently, i.e. not required.
- Written information in owners manual
- Yellow indication telltale
- Must be separate from any re-configurable display
- Bulb-check required, but not self-check
- Must use ISO symbol defined as Low Tire
- Audible warning not required
- If identifying pressure by position, use symbol of vehicle with indicators at tire
- Must illuminate not more than 10 minutes after any tire becomes significantly under-inflated
- Remain on until under-inflation resolved
- Can be manually reset according to manufacturer's instructions
- Prohibits any control that automatically disables TPMS (i.e. during calibration, off-road, poor road conditions, or high RF fields).
- Test conditions/procedures
- Have 45 days to petition for reconsideration of final rule
- NHTSA "believes that as technology matures, manufacturers will be able to improve the performance of indirect TPMS"
- Nothing requires manufacturers to install ABS
- **The 2nd part, Nov 1, 2006, requirement will be based on:
- NHTSA studies comparing tire pressures of vehicles without TPMS to pressures of vehicles with TPMS that do not comply with the 4 tire system (indirect systems)
- Submission of new data and analysis entered into the docket addressing hw the performance characteristics of particular types of TPMS satisfy statutory requirements when significantly under-inflated. The docket will remain open for such submissions.