The P0700 code is just the TCM telling the Engine Computer (ECM) that there is a code stored in memory of the TCM. So, if you were to scan only the ECM, like what AutoZone does for most people, it would indicate that there is a code stored in the TCM and its the problem with the vehicle, it's a cause, not effect.
You don't have to have the TCM plugged in to check for power on this circuit. Since it comes directly from the fuse box with the Key On. All you need to do with a multimeter is have one lead on the battery negative and the other lead touch the pin on the TCM connector.
It looks like this Trans Control Module only has one plug. And there is only one pink wire in the entire plug, With the key on very easily touch the red multimeter lead to that pin and it should read 12volts. If it doesn't, there is a wiring problem between that TCM connector and the fuse panel.
This is a very check to do. If there is no power. You'll have to trace that pink wire back until you find a break in the wire, or a corroded connector is going through on its way to that fuse panel. No need to replace the TCM harness plug. If there is power there, turn the key off, and verify that the pins on the connector were not spread apart too far and just not making contact. That happens a lot, some people jam a test lead into a connector pin and spread the pins and then it never makes contact again. and they think something else has failed. It's called Pin Fitment.
After you find the power issue, put the old TCM back in, because it's programmed to your VIN, and you will have to program a new one for it to work at all.
One of the things to be aware of, if you do not have 12 volts at the TCM pink wire. The only connector I see on that circuit is the connector at the Fuse Panel (under-hood). So, you can check that connector with the key off for any issues, but also that pink wire branches off from that same spot and goes to the actual Transmission itself. It powers up the shift solenoids and the torque converter lock up solenoid, this sounds complicated but it's not.
If power is missing at the TCM connector and you don't find an issue at the fuse panel connector, with the key off, try unplugging the connector at the Transmission that has that same pink wire in it. and retest at the TCM connector. If you are unsure of how to test the connector with a multimeter let me know and I'll make you a small diagram of how to do it. It should be a quick test.
You could use a test light but that will not verify a full 12 volts.
Images (Click to enlarge)
Wednesday, August 31st, 2022 AT 9:59 AM