Diagnosing P1126 (Techstream/Multimeter Questions)

[brauski]

So I'm trying to troubleshoot my P1126 code using the FSM, Techstream, and my dirt cheap multimeter. I have a few questions for yall to make sure I'm not an idiot and am going down the right road before I start buying parts.

I don't have the "LEXUS hand-held tester" the FSM mentions, but Techstream appears to show me Freeze Frame Data. I'm looking for my magnetic clutch current value. Not seeing it. Am I looking in the wrong place? Or is the unfortunate "You need the hand-held tester...just like they said" the case?

Also, I'm getting -5.94 ohms on my multimeter (which would mean I need a new TCM). Curious as to why I'm getting a negative. When I flip the leads, the multimeter isn't able to read anything, which doesn't make sense to me. This look right, or what am I doing wrong?

Thanks in advance!

Edit: Replaced the TCM and cleaned the throttle body. Runs like a charm now!

 

[white_lx]

You have the multimeter range set to 20k-Ohms, i.e. 0 - 20,000 Ohms. That means that your reading of 5.94 is 5940 Ohms, not 5.94 Ohms. Such a high resistance value would indeed indicate a burnt-out clutch.

Set the range to 200-Ohm (lowest range) and repeat the measurement. You can also first check the multimeter by touching the wires in the lowest range. Should give the resistance of the wires approx 1 Ohm.

That negative number and the fact that polarity matters makes your measurement highly suspicious. Are you able to check it with some know resistance values, e.g. some resistors? Or try another multimeter?

 

[brauski]

You have the multimeter range set to 20k-Ohms, i.e. 0 - 20,000 Ohms. That means that your reading of 5.94 is 5940 Ohms, not 5.94 Ohms. Such a high resistance value would indeed indicate a burnt-out clutch.

Set the range to 200-Ohm (lowest range) and repeat the measurement. You can also first check the multimeter by touching the wires in the lowest range. Should give the resistance of the wires approx 1 Ohm.

That negative number and the fact that polarity matters makes your measurement highly suspicious. Are you able to check it with some know resistance values, e.g. some resistors? Or try another multimeter?

Thanks for the quick reply. I'm getting 1.9 ohms between the leads which from my research checks for such a crappy multimeter. I don't have anything else to check it on unfortunately (heck, maybe I'll got test a light bulb or something).

And I'm still not getting a good reading. I've tried both polarities and all sorts of different positions witht he leads to ensure they're getting good contact, so I don't think that's the issue. I just replaced the batteries in the meter as well. Should I can this one and buy another? Or should I interpret the lack of a reading as out of limits?

Also of note, maybe I'm making stuff up now, but when I put the ignition to on, I get a high pitch humming from the TCM that I don't recall being there in the past. To verify it was the TCM, I unplugged the connector and it instantly stopped. but then again, I've never sat there with the hood open listening for sounds with the motor off and ignition on before. Would anyone be willing to see if their rig makes the hum?