SUBJECT VEHICLE: 2008-10 Mercury Mountaineer
RELEARN PROCEDURE? Yes.
SPECIAL TOOLS NEEDED? Yes, a TPMS Activation Tool (P/N 204-363) or equivalent.
The tire pressure monitoring system (TPMS) on the 2008-10 Mercury Mountaineer monitors the air pressure in the four road tires with wheel-mounted tire pressure sensors (TPS). The sensors transmit radio frequency signals to the Smart Junction Box (SJB) approximately every 60 seconds when the vehicle speed exceeds 20 mph, and every six hours when the vehicle is stationary.
Each tire pressure sensor transmission is compared against a low-pressure limit (pressure listed on vehicle certification label minus 25%, which will be about 6 psi to 9 psi). If it is determined that the tire pressure has fallen below this limit, the SJB sends a message to the instrument cluster, which then illuminates the low pressure warning indicator and displays the appropriate message(s) in the message center (if equipped).
The battery-operated tire pressure sensors are mounted to metal brackets (called cradles) on the wheels inside the tires. The sensors are mounted 180 degrees from the valve stems. The tire pressure sensor may be serviced separately, but the cradle and strap must be replaced together.
Under the following conditions, the TPMS may not function properly:
• Low tire pressure;
• The TPS is missing or damaged;
• Spare tire is installed as a road wheel;
• An incorrect TPS is installed;
• The TPS is installed incorrectly;
• Non-OEM wheels are installed;
• Non-OEM equipped run-flat tires are installed; or
• There are other non-OEM modifications (roll cages, service barriers, part racks, ladder racks, etc.).
TPMS warning indicators
NOTE: As ambient temperature decreases by 10 degrees Fahrenheit, tire pressures decrease 1 psi. If tire pressures are not adjusted at cold temperature, the tire pressure may drop enough to be detected by the TPMS, which will activate the low pressure warning light.
When the tire pressure warning light comes on solid and the message center displays “LOW TIRE PRESSURE,” check the air pressure of all tires and adjust to the specified cold pressure listed on the vehicle certification label (found on the driver’s door or door pillar).
Drive the vehicle at 20 mph for at least two minutes. Make sure the warning light goes off. If the warning light stays on, there is a malfunction in the TPMS. See appropriate manufacturer service information.
When the tire pressure warning light flashes for 20 to 30 seconds after a bulb check has been performed and the message center displays warning messages, there is a malfunction in the TPMS. See appropriate manufacturer service information.
Reset procedures
NOTE: If a TPS is replaced, it will need to be trained. The TPMS is not affected by wheel and tire rotation.
Drive the vehicle at 20 mph for at least two minutes. If the vehicle has been stationary for more than 30 minutes, the sensor will enter into a “sleep mode” and stop transmitting. A TPMS activation procedure may be needed.
See the instructions for TPS activation. Make sure the warning light goes off.
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TPS training
NOTE: In the following procedure, TPMS Activation Tool (P/N 204-363) or equivalent must be used.
NOTE: The TPS training procedure must be done on a single vehicle, in an area without radio frequency (RF) noise and at least three feet away from any other vehicle equipped with TPMS. RF noise is generated by electrical motor and appliance operation, cellular telephones and remote transmitters, power inverters and portable entertainment equipment.
NOTE: A new TPS is shipped in an OFF mode (or battery saver mode), and must be turned ON before it can be trained.
To turn the sensor on, inflate the tire to the recommended inflation pressure and wait at least two minutes, then continue with the sensor training procedure. The sensor also can be activated using the TPMS activation tool. See TPS activation.
1. Turn the ignition switch to the OFF position, then press and release the brake pedal.
2. Turn the ignition switch from the OFF position to the RUN position three times, ending in the RUN position. Do not wait more than one minute between each key cycle.
3. Press and release the brake pedal.
4. Turn the ignition switch to the OFF position.
5. Turn the ignition switch from the OFF position to the RUN position three times, ending in the RUN position. Do not wait more than one minute between each key cycle.
NOTE: It may take up to six seconds to activate a TPS. During this time, the activation tool must remain in place 180 degrees from the valve stem (see Figure 1).
If a sensor does not respond to the activation tool, attempt to activate the same sensor using the activation tool. If the sensor still does not respond, move the vehicle to rotate the wheels at least one-quarter of a turn and attempt to activate the same sensor again.
If the SJB does not recognize any one of the four TPSs during the tire training procedure, the horn will sound twice and the message center (if equipped) will display “TIRE NOT TRAINED REPEAT.” Repeat training procedure from the beginning.
6. The horn will sound once and the tire pressure warning light will flash if the train mode has been entered successfully (if equipped, the message center displays “TRAIN LF TIRE”). Place TPMS activation tool (P/N 204-363) on the left front tire wall opposite (180 degrees) from the valve stem. The horn will sound briefly to indicate that the TPS has been recognized by the SJB.
NOTE: Do not wait more than two minutes between training each sensor.
7. Within two minutes after the horn sounds, place the activation tool on the right-front tire wall opposite (180 degrees) from the valve stem (see Figure 1). Repeat the same procedure for the right-rear and left-rear tires (see Figure 2).
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8. When the tire training procedure is complete, the message center (if equipped) will display “TIRE TRAINING MODE COMPLETE.” For vehicles not equipped with a message center, successful completion of the training procedure will be verified by turning the ignition switch to the OFF position without the horn sounding. If the horn sounds when the ignition is turned off, the training procedure was not successful.
TPMS activation
1. Turn the ignition switch to the ON position.
2. Place the activation tool on the left-front tire wall 180 degrees from the valve stem. NOTE: A green light will flash and a beep will sound on the activation tool for each successful TPMS sensor response.
3. Press the test button on the activation tool to activate the TPMS sensor. For best results, activate each sensor twice. NOTE: If the tire pressure warning light is still illuminated after adjusting tire pressures and activating sensors, there is a malfunction in the TPMS. See appropriate manufacturer service information.
4. Repeat steps 1-3 for each tire.
Demounting/mounting procedures
CAUTION: The tire should be demounted from the wheel using the tire changer manufacturer’s instructions. Use the following information to avoid damage during the service procedures.
CAUTION: The tire and wheel must always be correctly matched. It is very important to determine the size of each component before any assembly operations commence. Failure to adhere to these instructions can result in an explosive separation and cause serious bodily injury or death.
Use only wheels and wheel nuts that have been designed for current model year Fords. TPSs are not designed to be used with aftermarket wheels. Aftermarket wheels or wheel nuts may not fit or function correctly, and can cause personal injury or damage to the vehicle. A wheel and tire assembly equipped with TPS will have the following verbiage stamped or cast on the wheel: “Sensor May Be Inside.”
Retighten the wheel nuts at 500 miles after any wheel change or any time the wheel nuts are loosened. Failure to retighten wheel nuts at the mileage specified can allow wheels to come off while the vehicle is in motion, possibly causing loss of vehicle control and collision.
NOTE: The use of run-flat tires (tires with steel body cord plies in the tire sidewall) when the vehicle is not originally equipped is not recommended, as it may cause the TPMS to malfunction.
If possible, use Digital Tire Gauge (P/N 204-354) any time tire pressures are measured to be sure that accurate values are obtained. Ford Motor Co. recommends the use of a digital or dial-type tire pressure gauge rather than a stick-type gauge for increased accuracy.
Removal
1. Remove the wheel and tire assembly. CAUTION: When using a paddle-type bead separator, ensure that the valve stem is positioned at 6 o’clock to prevent damage to the TPS.
CAUTION: Do not allow the tire beads to move beyond the wheel mid-plane when breaking the beads, or damage to the TPS may occur.
NOTE: Some machines may have a nylon roller bead separator at the 12 o’clock position instead of the paddle-type bead separator at the 3 o’clock position.
2. Position the wheel and tire assembly on a suitable tire machine with the valve stem at the 6 o’clock or 12 o’clock position, and separate both beads of the tire from the wheel. NOTE: Index mark the valve stem and wheel weight positions.
3. Place the wheel and tire assembly on the turntable of a tire machine with the valve stem between the 5 and 6 o’clock positions, and the machine arm at the 12 o’clock position. Demount the tire. CAUTION: Do not use a large screwdriver or apply excessive force in the following step, or damage to components will occur.
4. Using a pocket screwdriver, remove the sensor locking clip (see Figures 3 and 4). Detach the sensor from the cradle and remove sensor.
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Installation
1. Position the sensor into the cradle by inserting the hinge end of the sensor into the hook end of the cradle, and pushing the opposite end of the sensor down onto the cradle. Ensure the sensor is fully seated into the cradle (a “click” noise will be heard). NOTE: The locking clip can only be fully seated when installed in the correct orientation. If the locking clip cannot be fully inserted, the sensor may not be fully seated on the cradle or the locking clip may be inserted backward.
2. Insert a new locking clip into the TPS.
3. Place the wheel on the turntable of the tire machine so that the TPS is at the 6 o’clock position, and the valve stem and machine arm are at the 12 o’clock position. CAUTION: Use only a soap and water solution to lubricate the tire. Use of anything other than soap and water may result in damage to the TPS.
4. Lubricate and mount the tire onto the wheel starting 90 degrees from the sensor, moving away from the sensor. CAUTION: Do not inflate the tire higher than the maximum pressure stamped on the tire sidewall.
5. Inflate the tire to the pressure specified on the vehicle certification label (located on driver door or door pillar).
6. Install the wheel and tire assembly.
7. Train the TPSs. See Training under Reset procedures.
TPS strap and cradle
NOTE: While the TPS is available separately, the cradle and strap are only available as a kit. Though there are several different strap kits available based on wheel diameter, all kits share the same base part number.
Removal
1. Remove the TPS. WARNING: The strap is under tension. Always use safety goggles or a face shield and gloves when removing the band/strap. Failure to follow these instructions may result in personal injury.
2. To remove a dealer-installed strap, go to the next step. To remove a factory-installed strap, perform the following.
• Locate the strap buckle. Secure strap to wheel using duct tape on both sides of the buckle, about 0.98-inch from the buckle.
• Using a large screwdriver and a twisting motion, unbuckle the strap.
• Discard the strap.
3. To remove a dealer-installed strap, turn the worm gear screw until the strap is fully released from the worm gear. Discard the strap. NOTE: To aid assembly, mark the location of the cradle prior to disassembly.
4. Remove the cradle by inserting a screwdriver under the cradle and prying up.
Installation
1. Position the sensor into the new cradle by inserting the hinge end of the sensor into the hook end of the cradle, and pushing the opposite end of the sensor down onto the cradle. Ensure the sensor is fully seated into the cradle (a “click” noise will be heard).
CAUTION: Metal scrapers can damage the wheel. When removing the cradle adhesive strip residue, use only plastic or non-metallic scrapers. NOTE: The sensor and cradle must be positioned with the hinge side of the sensor on the right side when viewed from the curb side (beauty side) of the wheel. The sensor has raised markings indicating how to position it.
2. Clean the area where the sensor and cradle are to be installed. Remove the adhesive tape liner from the cradle, and position the sensor and cradle into the wheel drop well 180 degrees from the valve stem.
3. Install the tapered end of the strap through the opening of the cradle on the hinge side of the sensor. This will position the worm gear on the locking clip side of the sensor. CAUTION: Steel wheels have a “high spot” along their circumference. Ensure the strap is positioned in the lowest spot possible for correct sensor and cradle retention.
4. While keeping the strap parallel with the wheel flange, position the worm gear one-half to one inch away from the sensor and tighten to 27 in.-lbs. (3 N.m).
5. Place the wheel on the turntable of a tire machine so that the tire pressure sensor is at the 6 o’clock position, and the valve stem and machine arm are at the 12 o’clock position.
6. Lubricate and mount the tire onto the wheel starting 90 degrees from the sensor, moving away from the sensor.
7. Inflate the tire to the pressure specified on the vehicle certification label (located on driver door or door pillar).
8. Install the wheel and tire assembly.
9. Train the sensors. See TPS training. ■
Information for this column comes from Mitchell 1’s ”Tire Pressure Monitoring Systems Guide” for domestic and import vehicles through 2012. Headquartered in Poway, Calif., Mitchell 1 has provided quality repair information solutions to the automotive industry for more than 80 years. For more information, visit www.mitchell1.com.
For more TPMS articles, see:
Register Mazda sensors when changing tires or wheels
