How to use Multimeter (for ohms and volts)

Okay, have to be honest, not exactly sure if I am using this thing the right way. I am trying to backpin my TPS to check voltage AND backpin my warness hiring coming from my Transmission computer to check solenoid ohms.

Mulitimeter I have

So when I am checking volts for the TPS, I have read I am checking for 4.5 or so when throttle open, etc so what setting should I have that on?

And when I am checking ohms for the soleniods, I am looking for 12.6 ohms, etc so what setting should I put that on?

I appreciate the help.

Thanks,

Chris

20 VDC, and 200 Ohms respectively.

Here read this

As a general rule, figure the maximum voltage or number of ohms you would expect might occur, and set your range as close to that as you can. So for example, if you are working on a 12 volt system, setting the range to 20 or the nearest setting above 12 will give you the most fractional digits. If you set it to 200 you'll get a reading too, but it will be missing the fractional volts, thus not very useful in this application.

With a digital ohmmeter, remember that "infinite resistance," i.e. no circuit, no leakage, no nuttin', is usually represented by an 'out of range' or a single digit "1" , and perfect circuit or short circuit, by zero or "0.00." Just remember that zero ohms means zero resistance, and that is a short circuit, not no circuit.

If you're looking to test a CPS, which runs in the 200 ohm range, use that. If you are testing a wiring harness or a connector for continuity, the ideal is of course "zero ohms", so use the lowest ohm range available, so it will detect even the smallest resistance. If you set it to 20 megohms or something, it will not detect a minor fault. Remember that most ohmmeters have a fuse in them, and it might have a residual resistance of a few tenths of an ohm. Stick the two leads together first, to see what the error is.

If you're testing a harness or other component for leakage or suspected shorts, rather than continuity, the opposite rule would apply. You want to detect even a tiny leakage in the megohm range, so set the ohmmeter for the largest range first, and test.

Most digital meters will go at least somewhat beyond the range set without damage, but don't overdo it. If you accidentally get 30 volts on the 20 setting, you'll just get an "out of range" indication, but if you test a 220 volt circuit with it set at 20 you'll probably blow the fuse or the meter.

Matthew,

That is an awesome explanation, thanks.

So just to make sure I understand this correctly, what I am trying to do is:

1. "ohm" out the solenoids in the trans to see if they are working
2. Check the volts on the TPS to make sure it is correct when open or closed
3. Check to see if the TCU is receiving enough voltage from the battery
4. Check the resistance of the wire going from the TPS to the TCU to make sure it isn't bad.

1. So based upon that, from what I know, the ohms from the solenoids go up to 20.xx, etc so I would want to set it to 200 Ohms?

2. To check the volts on the TPS I would set the meter to 20VDC?

3. Check the volts going to the TCU from the battery I would put it on 20VDC again or ohms?

4. Check resistance on the wire from TPS to TCU, what would I set this to? From what I know about the TPS is that it goes from 200 (closed) to around 4.5v (open).

Again, thanks for the help.

Chris

Double Down said:

Matthew,

That is an awesome explanation, thanks.

So just to make sure I understand this correctly, what I am trying to do is:

1. "ohm" out the solenoids in the trans to see if they are working
2. Check the volts on the TPS to make sure it is correct when open or closed
3. Check to see if the TCU is receiving enough voltage from the battery
4. Check the resistance of the wire going from the TPS to the TCU to make sure it isn't bad.

1. So based upon that, from what I know, the ohms from the solenoids go up to 20.xx, etc so I would want to set it to 200 Ohms?

2. To check the volts on the TPS I would set the meter to 20VDC?

3. Check the volts going to the TCU from the battery I would put it on 20VDC again or ohms?

4. Check resistance on the wire from TPS to TCU, what would I set this to? From what I know about the TPS is that it goes from 200 (closed) to around 4.5v (open).

Again, thanks for the help.

Chris

Click to expand...

I PM'd you so won't repeat here. Can continue there if needed.