Tire Monitor System - Ins And Outs
Tire Pressure
Monitoring System
Ins and Outs
The Tire Pressure Monitoring System
(TPMS) does just what its name implies it monitors tire pressures on a vehicle.
There are two type of Systems employed on Hyundai models. The first type of system or "High-Line" monitors sensors mounted to each wheel and illuminates an indicator lamp in the instrument cluster indicating which tire should be checked for air pressure. The other type of system, called "Low-Line" monitors sensors mounted to each wheel and illuminates an indicator lamp in the instrument cluster showing that one or more tires' air pressure should be checked; however, the location of the tire is not specified. All vehicles sold in the United States for the 2008 model year must have TPMS installed. The "High-Line" system is used on the Santa Fe, Entourage and Veracruz. The "Low-Line" system can be found on the Azera, Sonata, Tiburon and Tucson.
Monitoring on the "High Line" system begins with a key ON sequence. At that moment, the TPMS receiver sends a "wake up" signal to each wheel's low frequency initiator (LFI). The LFI in turn send a LF signal to the corresponding Wheel Sensor to activate it. The Wheel Sensors periodically measure pressure, temperature of moving tires (obviously, not the spare) and relay that data via radio frequency signal back to the receiver. The information is analyzed by the receiver and, if necessary, a warning signal is illuminated.
In the "Low-Line" system there are no LFI units. The receiver communicates directly with the wheel-mounted sensors. The TPMS indicator in the instrument cluster does not indicate which tire triggered the signal light. Attach the TPMS Exciter to determine where the issue is. The wheels are identified as Si, S2, S3, and S4. If the receiver in either system is replaced, the correct VIN must be registered into the new one using the TPMS Exciter. The same is true for replacement of any wheel sensor. The best procedure is to re-enter the ID of all wheel sensors on a vehicle, even if only one is changed out. Note: Make sure that the Exciter has the latest updates. You can check for them at hmaservice.com. The most current version is dated "12-20-06." See "How to Update" on the website or check out the cover article in the TechNet Times Issue 16 Volume 5.
Tires must be inflated to their specified pressures for optimum vehicle ride, handling and tire wear. Currently, 2006 and 2007 Hyundai models are shipped to dealers with all full size tires inflated to approximately 45~48 psi air pressure. The tire pressures are set higher than specification at the vehicle assembly plants to ensure proper tire bead seating and to minimize "flat spotting" on tires during transportation and storage.
It is each dealership's responsibility to ensure that the tire inflation pressure is set to the proper specification during the Pre-Delivery Inspection (PDI) and that the pressure is correct at the time of vehicle retail delivery.
NOTE:
Most 2007 Hyundai models are equipped with the TPMS (Tire Pressure Monitoring System). If the tire inflation pressure is not set to the proper specification at the time of vehicle retail delivery, the TPMS light may illuminate. NOTE:
Compact spare tires are inflated to their higher specified pressure at the assembly plant, approximately 60~65 psi. Always refer to the tire placard on the vehicle for correct tire pressure specifications when checking and adjusting tire pressures.
If a customer comments that the TPMS (Tire Pressure Monitoring System) tire pressure warning lamp is "ON" for the first few miles of driving after a cold start or stays "ON" continuously, particularly in cold ambient temperatures, please be sure to inform the customer that the system is operating correctly to warn of a low tire pressure condition, and a system diagnosis may not be required.
The customer should be made aware of the following:
This condition may be caused by low tire pressure if the tire pressure falls below the low warning threshold for any reason including low temperature effects.
NOTE:
For vehicles equipped with the TPMS, the threshold pressure limit is 25% below the vehicle's recommended cold tire pressure, shown on the placard located on the driver side B-pillar.
^ Recommend to the customer to inflate tires when they are cold. NOTE: The tire pressure will vary with temperature by about 1 psi (6.9 kPa) for every 12°F (6.5°C).
^ Recommend to the customer to check and adjust all wheels' tire pressures, including the spare tire, once a month. (For additional information, request the customer to refer to the vehicle owner's manual).
The TPMS malfunction indicator lamp may be illuminated if the vehicle is moving around electric power supply cables or radio transmitters at police stations government and public offices broadcasting stations military installations airports transmitting towers etc. The TPMS indicator lamp generally turns off after the vehicle is removed from such interferences.
If the TPMS indicator lamp is ON and all four wheel sensors are checked and are working correctly external electronic devices connected to the vehicle's power outlets (notebook computer seat warmer massager coolers etc.) may be the cause of this condition. If any of these conditions are confirmed request the customer to not operate external electronic devices that cause this condition.
For more information about TPMS operation and diagnosis please see TSBs # 05-50-013 & 05-50-014 and TechNet Times Volume 15 Issue 6. All are available for viewing at hmaservice.com.