Originally Posted by
1project2many
1) ECM will monitor voltage.
2) Extra? Both of those sensors can be thought of as potentiometers. The 5V reference is "split" between ground and the signal wires. When the resistance between the signal wire and power is high, the signal voltage is low. When resistance between 5V and signal is low, signal voltage is high. Open the ground circuit and the signal line will go to near 5V.
3) Hmmm... Current always flows from negative to positive (although many of us were taught otherwise in school). There are charts on the internet and in the factory service manual which match up resistance to temperature.
4) The ecm reads the voltage on the positive wire to CTS. As the resistance through the sensor changes so does the voltage between the supply line and ground. Both the two and three wire sensors require a roughly equivalent strategy for the ecm to detect voltage sensor. The temp sensor is only two wires due to the nature of the sensor.
The ecm needs to be able to switch the direction of current flow through each coil in order to make the motor work in both directions.
They've gone to low voltage for many circuits today and tried to combine as many control circuits as possible with CAN communications. They're running things so tight that we see problems with terminal overheating and connector failure when a component draws just 2-3A over specification!
That there is some baaad luck.
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