March 23, 2011
Focusing on the Ford F-Series
Smart Junction Box sends a message if pressure drops
By: Information provided by Mitchell 1
Figure 1
SUBJECT VEHICLE: 2010 Ford F-Series.
SENSOR IN TIRE? No (sensors/transmitters are installed in wheels).
RESET PROCEDURE? Yes.
SPECIAL TOOLS NEEDED? Yes (T10 Torx, TPM Activation Tool (204-363).
When a 2010 Ford F-Series vehicle is moving 20 mph or greater, the tire pressure monitoring system’s wheel-mounted tire pressure sensors transmit radio frequency signals to the Smart Junction Box (SJB) every 60 seconds. Each transmission is compared against a low-pressure limit (pressure listed on the vehicle certification label minus 25%, which will be about 6 to 9 psi). If a tire’s pressure falls below this limit, the SJB sends a message to the instrument cluster, which then illuminates the low pressure warning indicator.
To remove an old sensor, follow these steps.
1. Remove the wheel and tire. The valve stem is connected to the TPMS sensor, so do not pull the valve stem from the wheel to avoid damaging the sensor.
2. Remove the valve stem core and fully deflate all air from the tire.
3. Remove the tire from the wheel following the tire manufacturer’s directions.
4. Remove the TPMS sensor from the valve in the following sequence (see Figure 1):
a. Using a T10 Torx, remove the valve stem-to-TPMS sensor screw.
b. Carefully and firmly pull the sensor straight down and separate it from the valve stem.
5. Using a suitable valve stem puller and a wood block, remove the valve stem from the wheel.
6. If the TPMS sensor is being reused, inspect the TPMS sensor for damage and install new parts as necessary.
Before installing the replacement sensor, the valve stem must be installed onto the TPMS sensor and then installed into the wheel as an assembly.
Now you can install the replacement sensor by following these seven steps.
1. Install a new valve stem onto the TPMS sensor, tightening the valve stem-to-TPMS sensor screw to 13 in.-lbs. (1.5 Nm). It is important to pull the valve stem and TPMS sensor assembly through the wheel rim hole in a direction parallel to the valve stem hole axis.
2. Lubricate the valve stem with suitable fast-drying, corrosion-inhibiting tire bead lubricant and install the valve stem and TPMS sensor assembly into the wheel using a block of wood and a suitable valve stem installer. Do not mount the tire at this time.
3. Make sure the valve stem rubber is fully seated against the wheel.
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