System warning light in 575SA

gphpe · Feb 15, 2009

tazandjan said: ↑

Contender, Brian- I think I have the TPMS SD2 vs tire pressure calibration button answer. I was reviewing a set of maintenance records for a 575M HGTC for a fellow Fchatter to see what services he needed to complete when he receives his new car. One of the items in the records was calibrating the TPMS with an SD2. This was done without having to drive the car. What I think the TPMS system allows you to do is calibrate the tire pressures two ways, one while the car is stationary as part of an SD2 analysis, and the other using the calibrate button and driving the car while the ECU performs the same steps the SD2 shortcuts in time. This is consistent with all the technical data I have seen from Beru and in the 575M WSM and owner's manual. It is also the logical way to do things, because a technician would not want to drive a car 20 minutes to calibrate tire pressures and would not want to send the car out with a TPMS warning light if he added air to a customer's tires.

There are four separate antennas for the TPMS, so the ECU has all the information it requires to assign a sensor to a location and then calibrate to the individual tire pressures. The SD2 can perform the same functions, as well as test for battery strength of the individual sensors, and probably some other TPMS diagnostic funtions, of which I know nothing and Brian is the expert.

We are getting service TPMS lights now because at least one of the sensors is reaching Beru's stated five to seven year battery life limit. It only takes one low sensor battery to cause a service TPMS light. The five to seven year battery life undoubtedly varies between makes of cars because of differences in antenna placement and wheel/tire type. It appears Ferraris are on the low side for battery life.

I was waiting for a pair of 30 mm rear wheel spacers before mounting my new TPMS sensors so I only have to remove the rear wheels once, but may go ahead if they do not arrive soon. They will not be done before the week of 16 February, however.

Taz
Terry Phillips
Click to expand...

Taz,

Interesting thread. I learned a lot about TPMS. If you change all four sensors, how does the ECU determine (by driving 20 minutes)exact location of the new sensors (RF,LF,RR or LR), without programming the ECU to identify sensor location? I can understand using SD2/3 for assigninmg sensor location.

tazandjan · Feb 15, 2009

Simple, there are four antennas, one for each wheel. Look at the diagram in your owner's manual. All the ECU has to do is assign the wheel sensor to the matching location antenna. Signal strength is strongest on the nearest antenna to each wheel. Some systems have five antennas and can tell you when your spare is low as well.

Taz
Terry Phillips

gphpe · Feb 16, 2009

Thank you Taz. No owners manual, because I do not own a 575. Ha! You are correct about signal strength. I read the article on Beru website that explained how the system locates the correct sensor by using a trigger signal. I hope that you get the system working correctly by changing the sensors.

Gary

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System warning light in 575SA

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tazandjan Three Time F1 World Champ
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System warning light in 575SA

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tazandjan Three Time F1 World Champ Lifetime Rossa Owner

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tazandjan Three Time F1 World Champ
Lifetime Rossa Owner