[Falcao]

Hi, I am curently designing a custom board, based on your schematic, but I wonder why there is no pull up resistor for TPS and O2 sensor ?

Thank you very much

[pazi88]

Both tps and o2 controller put out values between 0-5v without any pull-up.

If you are designing custom pcb, I would recommend you to more carefully study how different components in engine setup work, so you avoid as many problems as possible when doing the design. Like for example google how tps works and maybe play around with tps sensor on your work bench, so you understand how it works and why it doesn't need pull-up.

[Falcao]

Well I know how a TPS works, but we could putt a pull up resistor to 5v and then using only two pins of sensor connector, ground and signal, right ?

Is it wise to put a pull up to all my signal inputs, with a jumper to choose either to use it or not ?

[PSIG]

Well I know how a TPS works, but we could putt a pull up resistor to 5v and then using only two pins of sensor connector, ground and signal, right ?

Yes, but that would be a non-standard and special-use case. You do understand that a TPS provides its own internal version of a pullup, right? It would make more sense that a standardized board be used and add the single pullup resistor for your one special use. Else, you are taking the time, effort and expense to design a board for only your use. Additionally, a TPS used in this way would require only a specific TPS be used that matches the pullup properly for correct function; or conversely a specific pullup resistor that will only match that one TPS specification. Do as you like, but I suggest you take time to understand the internal function of the sensors, the code and how it is designed to use the intended signals, and the various consequences of using unusual methods to read them.

Is it wise to put a pull up to all my signal inputs, with a jumper to choose either to use it or not ?

Generally, no. There are general standards and methods proven across decades of use. Again, unless performing a special operation for a special use or universal input application — I would suggest following established methods. Adding unnecessary pullups/downs adds complication, board space requirements, and cost. Your O2 example is not configurable for pullup/down, which could indicate you are not yet fully familiar with automotive sensors and their operation or application. Continue studying!

David

[Falcao]

Thank you for your answer.

You are right saying I am specially designing the board for me, to suit my needs. The extra cost and board space is not a problem, but I want my board to have as much as possible sensors' inputs, like oil pressure, oil temp, fuel pressure, fuel level, ect...

And as I don't know yet what type of sensor I will be using, I guess pull up possibility for inch entry is a solution, except for already defined sensors, such as TPS or O2.

But I do understand that it's better to handle sensors the way they're susposed to, and I will