Can You Bypass ECU Sensors with Resistors in Automotive Projects?

[audiguy]

Hi,

I'm a new member looking for a little help.

I'm working on an automotive suspension project where we replace "electronic damping control" struts with a coilover that has no sensor. I'm looking to bypass the sensor and trick the ECU to thinking they are still hooked up. The resistance of each damper is 2.3 ohms and runs on a 12 volt system, with a 2 wire connection to each. Could I run a 3ohm resistor on each wire into a diode to trick the ECU? Any thoughts?

 

[MATLABdude]

Welcome to PhysicsForums!

Not knowing the specifics of the setup or even the sensor, I'd say it's probably worth a try (as long as the resistor is put somewhere where, if it starts on fire, nothing bad happens).

Ideally, you'd figure out the response of the sensor--does the resistance change, is it actually a coil / something else, what's the voltage across the sensor, etc. Since ECUs are usually pretty well documented (assuming you have the service manual, or better yet, the manual for the ECU itself), you may not even have to do any characterization / testing.

Once you've figured out what the sensor is (and how it works) it becomes much easier to replace. Unless you already know this and are asking on the assumption that we also know (which we don't).

EDIT: You can find a 1W 2.3 ohm resistor on Digikey, but you really need to find out how much power the resistor of the sensor dissipates.
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=2.3ACCT-ND

 

[dillonjerry]

I'm concerned about the fact that you are talking about using a 3 ohm resistor for a 12 v circuit. I think we need to know more about the sensor that you are talking about. What does this sensor read? Its quite possible that the resistor will catch on fire as the previous post warns about. You might need a 10w wire coil resistor or something similar.