Understanding OHMs law in relation to transmissions and diagnosis basics is essential. Lets go over OHMs law first, this explanation and chart should make it understandable.

1. Ohms law consists of three factors which are A. voltage, B. resistance, and C. current.
Resistance is measured in ohms and current is measured in amperage or amps. Ohms law states that if any two of these three factors are known, the third factor can be determined with simple basic math.

The Ohms chart is shown below. Take note of the large letters E, I, and R. The “E” is the voltage factor, the “I” is the amperage factor, and the “R” is the resistance factor.

To make it easier for you to understand and apply it to your diagnostic work, I inserted the letters V, A, and R to represent Voltage, Amperage, and Resistance. You will need to either multiply or divide.

This is the easy way to remember. Examples: To determine the amperage, divide the voltage (E) by the resistance (R). Simply use the horizontal line to remember to divide. Again using the horizontal line, divide the voltage (E) by the amperage (I) to determine the resistance. To determine the voltage (E) multiply the amperage (I) by the resistance (R) using the vertical line.

If you want to fix your transmission problem, this is an essential ingredient for the mix. If you are going into a diagnosis with thought of changing parts until your transmission works, you might as well go ahead and save some time a money, just go buy a rebuilt transmission and get it over with. Be pre-warned, sometimes a transmission goes bad because of an external inputs such as a bad sensor or computer. If so, then you will be buying another rebuilt transmission until you solve the root problem first.