TPMS System - Operation/Run Flat Tire Information
NO: 77-12DATE: 6-2-2005
MODEL: S60 / V70 / S80
M. YEAR: 2005
SUBJECT: Tire Pressure Monitoring Systems & Run Flat Tires
REFERENCE: VIDA / VADIS
DESCRIPTION:
TPMS (Tire Pressure Monitoring Systems) are now part of the Run Flat tire
program being offered under option code 000649. A customer with tire pressure monitoring may experience a warning message in the DIM if a tire is low on pressure. This could be viewed as a customer complaint. This TNN has been developed to give the technician a better understanding of the TPMS system and to also understand why it is used.
Run Flat Tires can be grouped into several categories; Self Supporting Tires (SST) and Auxiliary Supported Tires (AST) both require special tire changing equipment to remove and install the tire. The most common AST is the known as "PAX".
SST - Stiff sidewalls allow limited driving after a tire has lost pressure. SSTs are also commonly referred to under the larger category of Run Flat Tires. This is the type of run flat tire currently available on Volvo cars.
PAX - When tire pressure is lost, an auxiliary ring attached to the wheel, located inside the tire, allows the weight of the vehicle to be transferred to the wheel. This accomplishes limited driving on a tire that has lost pressure. This type of tire may become available in the future.
Note:
When purchasing tire changing equipment Volvo Retailers are advised to purchase equipment that can handle both SST and PAX Run Flat Tires.
Additionally, if tire changing is accomplished by a sublet shop, Run Flat Tires should only be sent to qualified shops with the correct equipment.
Background:
A U.S. federal regulation requires that vehicles equipped with run flat tires must also be equipped with a system to warn the driver if the pressure in any tire drops 25 percent or more below the recommended tire inflation pressure. This is why today's Volvos sold with run flat tires have TPMS (Tire Pressure Monitoring System).
Additionally, U.S. FMVSS 138 (Federal Motor Vehicle Safety Standard 138) will eventually require all vehicles 10,000 pounds (4,536 kg) GVWR or less to be fitted with tire pressure monitoring systems. This requirement is being phased in as shown below. This requirement affects all vehicle manufactures in the U.S.
Phase-in schedule according to today's FMVSS rule.
^ 20% on cars produced during OCT 2005 to AUG 2006;
^ 70% on cars produced during SEP 2006 to AUG 2007;
^ 100% on cars produced after SEP 2007.
SERVICE (Run Flat Tires):
When removing or installing a run flat tire, only equipment
certified for run flat tire mounting should be used. Check with your equipment manufacture to determine if you have the proper machine and the recommended accessories to properly perform this replacement. Your equipment manufacture should also be able to provide equipment training if required.
Additional Instructions:
1. When removing a valve transmitter assembly from a wheel the seal A should be replaced prior to reinstalling the valve assembly. Included in service kit 30736598.
2. The valve nut B should be tightened to 7.5 Nm (5.5 ft-lbs)
3. Only nickel coated valve cores C should be used. Brass cores will result in galvanic corrosion. Included in service kit 30736598.
TPMS Function:
TPMS uses four pressure-sensing transmitters, one incorporated in each wheel. Each pressure sensor transmits a signal to the UEM about tire pressure from each individual wheel. After the vehicle reaches sensor activation speed (4 - 20 mph) each sensor will transmit a pressure reading approximately once every minute, this will continue until the vehicle drops below the activation speed. The UEM acts as the receiver and turns on a DIM message if a tire's pressure should drop below specification.
The DIM does not provide information about which tire is low on pressure. Therefore, a DIM warning message is cause to check the pressure in all four tires.
TPMS Function: Messages associated with TPMS.
Note:
TPMS looks at each tire individually and if the pressure is low in one or more tires the warning message will illuminate.
TPMS Service:
Once the tire pressure is corrected, the vehicle will need to be driven at or above the activation speed before the warning lamp will go out. The correct specification for tire pressure is (38psi cold for S60 & V70) & (39psi cold for S80). No optional tire pressures can be used for vehicles with TPMS.
Note:
Sensor activation can also be simulated using the special tool (9512963) for testing the sensor.
See VIDA / VADIS
Vehicle Communication / UEM / Quick test of tire pressure sensor.
Note:
If a sensor is replaced the sensor will need to be identified by the UEM. This can be achieved by activating the sensor with special tool 9512963 or by driving the vehicle above activation speed for more then 5 minutes.
The temporary spare is not equipped with a tire pressure sensor. A customer driving on a temporary spare will see a DIM message appear within a few minutes of starting each time they drive.