DIY - Bypassing Tire Pressure Warning System (TPWS / TPMS)

[CTScott]

Originally Posted by CTScott

OK. Linny just PM'd me. His had been working fine until he headed out of town for Thanksgiving. All of his trips prior had been short (<6 miles). About 15 minutes into his trip the light came on.

So, it looks like this solution does not work - It looks like the third component is time.

Looked into it a bit more. The TPMS starts a timer once it receives power. After ~15 minutes of power and no comm from the sensors it turns the light on.

I am now experimenting with just using the brown wire, which is the output to the combination meter. To turn the light off, the TPWS module supplies ~4.0V to the brown wire. At 2.4V or less the light will come on.

I disconnected the TPWS and applied ~4.0 V to the brown wire (via a resistor voltage divider from the 12V supply on the connector). The light does not light. I will drive around for a week or so to make sure that eliminating the module doesn't cause a DTC to be thrown.

[ivanmadeline]

Thanks for the help.

[CTScott]

Originally Posted by CTScott

Looked into it a bit more. The TPMS starts a timer once it receives power. After ~15 minutes of power and no comm from the sensors it turns the light on.

I am now experimenting with just using the brown wire, which is the output to the combination meter. To turn the light off, the TPWS module supplies ~4.0V to the brown wire. At 2.4V or less the light will come on.

I disconnected the TPWS and applied ~4.0 V to the brown wire (via a resistor voltage divider from the 12V supply on the connector). The light does not light. I will drive around for a week or so to make sure that eliminating the module doesn't cause a DTC to be thrown.

OK. I've been driving around today with the TPWS disconnected as above, and no TPWS light. We are going out to dinner tonight, and where we are going is about 35 minutes away, so that will be a good test. If the light remains off and I still don't have any DTCs logged, when I get home tonight I'll post the updated method.

[CTScott]

Originally Posted by CTScott

OK. I've been driving around today with the TPWS disconnected as above, and no TPWS light. We are going out to dinner tonight, and where we are going is about 35 minutes away, so that will be a good test. If the light remains off and I still don't have any DTCs logged, when I get home tonight I'll post the updated method.

OK. The new solution looks good. After a bunch of short trips and a 30 minute each way dinner run, no TPWS light and no logged DTCs. The new solution goes as follows (and does not require the system to have been light-free prior):

This procedure requires some minor soldering and can be done with or without a switch to re-enable the TPWS.

1. Make a simple voltage divider to provide ~4 Volts to the TPWS light input to the Combination meter.



Parts Required:
3 150 ohm resistors (radio shack part # 271-1109 for a 5 pack)
22 AWG Wire (Red, Black, green (also yellow and blue if using switch)
Switch(optional), SPDT toggle or push on/off (Radio Shack part # 275-1555)
Heat shrink tubing or electrical tape
18-22 AWG (red) tap-splice connectors (3 for no switch, 4 for switch)

a. Solder three 150 ohm resistors end to end.
b. Solder a 6" piece of black wire to one end and a 6" piece of red wire to the opposite end of the string of resistors.
c. Solder a 6" piece of green wire between the first and second resistor from the black wire end.



d. Cover the resistors with heat shrink tubing or electrical tape.



e. Skip to step 2 if not adding a switch.
f. Solder a 6" piece yellow wire to the center terminal of the switch
g. Solder a 6" piece of blue wire to one of the end terminals of the switch.
h. Solder the free end of the green wire to the other end terminal of the switch.



i. Cover the exposed switch terminals with heat shrink tubing or electrical tape.




2. With the car powered off, unplug the TPWS module connector
3. Clip the brown wire (leave a couple of inches so you can reconnect later if so desired)



4. Using a tap splice, connect the red wire to the red wire on pin 7 (This red is next to an empty spot at position 8 {RED, empty, white, white, grey, black})
5. Using a tap splice, connect the black wire to white wire on pin 9 (Next to the empty spot after the red wire {red, empty, WHITE, white, grey, black})



6. If not using a switch, connect the green wire to the brown wire which goes to the combination meter (not the connector end of the cut wire).
7. If using the switch, connect the blue wire to the brown wire which goes to the combination meter (not the connector end of the cut wire).
8. If using the switch, connect the yellow wire to the other end of the brown wire, which is attached to the connector.
9. If not using the switch, leave the TPWS connector off. If using the switch, plug the connector into the TPWS.
10. Turn on the ignition. If not using the switch, the TPWS light should be off.
11. If using the switch and the TPWS light is on, press the switch and the light should turn off.