Bidirectional Scan Tool
Today's enhanced scan tools scan codes and display datastream but also have a bidirectional function capable of activating components like the fan motor, fuel pump, a/c clutch, etc.
Activating an actuator with the scan tool's bidirectional function can save diagnostic time.
If the component activates, we know that the ECM command, the part, and the circuit are working. This function bypasses the inputs like the switches and sensors the computer module uses to make decisions.
Now, the diagnosis switches to testing the engine coolant temperature sensor. The ECT tip is in the engine's coolant stream. It measures the temperature of the coolant as it passes.
When the coolant reaches a specific temperature, the control module activates the fan circuit to draw air through the radiator, typically at low speeds and idle. Enhanced scanners scan for codes, perform ECU coding and relearn, datastream, system tests, bidirectional control testing, maintenance reset, and more.