This how-to walks you through reprogramming the TPMS system in a first gen FX.
(special thanks to ModMe at myg37 forums)
This is my first write-up on IS.
If you find this guide helpful, please hit the THANKS button!!
This procedure was performed with success on a 2008 FX AWD.
PURPOSE / USAGE
The TPMS system should be reprogrammed whenever new TPMS wheel units are used. This typically happens when switching from summer tires to winter tires or if using newly installed/purchased wheel units. The TPMS system does not save previous wheel sensor settings. If you had your summer wheels on, switched to winter wheels and reprogrammed, and now want to go back to summer wheels, you have to reprogram the system.
Note: you do not need to reprogram the system if you are rotating tires or have a low pressure warning.
MATERIALS / TOOLS
3 to 4 feet of copper wire
What we're going to do is tap into the TPMS system and force it into learning mode. Learning mode is when the system actively looks for new TPMS sensor signals. If you've ever used a Bluetooth device, it's the same concept as mating it with your cell phone or laptop. We'll place the system in learning mode and mate the system to the new sensors. Once mated, your TPMS system will operate normally - it will read the tire pressures and alert you if the pressures are out of range. Most importantly (to me), the TPMS warning light on your dashboard will finally go off!
STEP BY STEP INSTRUCTIONS
1) By the driver's side left knee, remove the entire fuse cover plate (not just the fuse door) by unscrewing the plastic screw. You may also need to remove the plastic trim by the door sill to pull the left edge of the cover plate out. Carefully pry the plastic trim up with the flathead screwdriver to dislodge the tension clips. The removed cover looks like this:
2) Take your 3 to 4 foot wire:
and strip the ends of both to about an inch. Leave one end and with the other, take a few copper strands and wind them together. Fold the rest back. Then put this aside for now.
3) Now get your head under the dashboard on the drivers side. There are several wiring bundles running by the fuse panel. Look for a thick one that is vertical and has a black zip tie on it. The zip tie is at about the same height as the emergency brake pedal location.
Above the zip tie about 2 to 3 inches you'll find a white female wire connector taped with electrical tape to the large wire bundle. Carefully cut the tape to pull down this connector. It has one green wire connected to it. This is our connector.
4) When looking at the connector's female end you will see 4 holes. There are 2 small holes and 2 large holes. If looking at the connector like this, the green wire goes into the left side. We are interested in the top left hole - the small hole on the left side where the green wire is connected. In this image the top left hole looks slightly larger than the top right hole because I've inserted a wire into it so many times.
5) Take the wire you set up earlier and carefuly insert the thinned and wound end (from step 2) into the top left small hole on this connector. Make sure you push it as far in as it will go. If the wire slides out easily, add a few more strands and try again. We want this end of the wire to stay inserted in the hole.
6) Now turn your FX to the Key On Engine Off position (KOEO). This is the position right before starting the engine. Your dash lights should come on, including the TPMS warning light. Immediately after turning to KOEO, take the other end of your wire and tap it on the metal rim of the cigarette lighter by the transmission shifter. Tap it 5 times. You don't have to tap super-quickly, but don't do it really slowly either. About one tap per sec for 5 secs is good. You must start tapping immediately after KOEO. As you are tapping and counting your taps keep an eye on the TPMS indicator. After the 5th tap, it should start flashing. The flash sequence we want is 0.5 sec on and 0.5 sec off. Sit and watch the indicator lamp flash for one minute or 60 flashes. If it keeps flashing - congratulations, you just placed your TPMS system into learning mode. For now, turn the key to the off position.
If it flashes for 60 seconds and then goes solid, you should clear the system by performing the TPMS Error Clear procedure.
7) Now that you can successfully get your TPMS system into learning mode, it's time to actually do the learning. In order to do this, you need to do two things. First, the tires on your FX must be set to specific tire pressures. Second, you need to drive over 45mph for approximately 5-10 minutes. The pressures are:
Front Left 34 psi
Front Right 31 psi
Rear Right 29 psi
Rear Left 26 psi
Notice these pressures decrease going clockwise around the car starting at the front left. (FL, FR, RR, RL) This is actually how your FX reports the pressures in the TRIP section of your display.
It's very important that these are the tire pressures when your TPMS system is trying to learn. If they are off, even by 1 psi - it won't work. Also, the system requires that the wheels are spinning in order for the FX to read the sensor data. I tried this whole procedure many times and could only get my FX to read the sensors at highway speeds. So using side streets at 25-35 mph may not work.
7a) Drive your FX for 10 to 15 mins to warm up the tires. Stop at a gas station at a highway rest area or right off a highway. Set your pressures in the parking lot with your warm tires. See above for the pressures.
7b) After setting your tire pressures, use your wire to enter TPMS learning mode. Once the TPMS indicator starts blinking, wait at least a minute to make sure it keeps blinking. Then start the car. Go directly from KOEO to engine on. Do not turn the car off and then on again, this will interrupt the TPMS learning mode. (If you like, instead of working from KOEO you can start the car and then tap the wire to enter learning mode. It's up to you.) Immediately get on the highway and drive at highway speeds.
8) Drive for 10-15 minutes or until the TPMS light goes off. If the light goes off, congratulations - you have just successfully reprogrammed your system. Navigate to the tire pressure screen on the TRIP display and you will see your tire pressures. If the light continues to flash after 15 minutes of highway speeds, your tire pressures probably aren't right. Head back to a gas station and check them. The re-enter learning mode and try again.
9) Once complete, all you have to do now is fill your tires back to the normal operating pressures and you're done. During this interim time the TPMS light may come back on indicating a low pressure situation. Just fill your tires up and the light should go off.
10) Don't forget to put your sill trim and fuse cover plate back on over the connector plug. You don't have to retape the connector to the wire bundle, but you can if you want to.
1) I can't find the TPMS female wire connector.
The connector is attached to the thick wire bundle about 4-6 inches higher than the emergency brake pedal. Either get your head as far under the dash as you can so you can see it, or glide your hand along the wiring until you feel it.
2) Why tap the wire on the cigarette lighter rim?
Because we need to ground the connection, and the cig lighter rim is the easiest thing to use. There is steel under the dash you could also use, but I found that it was difficult to contort my body to accurately hit the steel and also watch the TPMS indicator at the same time.
3) I am tapping the wire but the TPMS indicator isn't blinking. Should I just keep tapping it?
No. You should only tap it 5 times and stop. If the indicator isn't blinking make sure the wire is inserted into the interface plug as far as it will go and that you're tapping the end on a good ground. Some of the metal under the dash is not grounded properly (connected to plastic or has paint on it etc) This is why I like to use the cig rim.
4) My TPMS indicator light blinks and then goes solid.
This is an indication of an error in the system. Clear the system by performing the TPMS Error Clear procedure then try again.
5) I've driven for over 20 minutes at highway speeds and my TPMS indicator light is still blinking.
Make sure the system is in learning mode (0.5 sec on / 0.5 sec off blink pattern) If it is, then most likely your tire pressures are off. Reset the tires to the pressures described in step 7. Remember, tire pressures change as temperatures increase. You'll have the best luck when performing the learning procedure on fully warmed up tires.
TPMS ERROR CLEAR PROCEDURE
This procedure will clear most of the error codes from the system. (There are 1 or 2 critical faults which can only be cleared by a consult tool) In order to clear the most common faults:
1) Ground the TPMS connector and hold it grounded
2) Continue holding it grounded, turn the car to KOEO or to full on
3) Continue holding it grounded, count to 10
4) Continue holding it grounded, turn off the car. After 5 seconds, release the ground.