51
Presented by Bob Pattengale
BOSCH MTS 5200 LAB SCOPE
1-800-71-TRAIN (1-800-718-7246) OR www.auto-video.com
THE GRAPHING MULTIMETER
Frequency
For this type of signal it is important to keep an eye on the minimum and maximum values. This
is because if you had a Ford vehicle that had a hesitation problem, you would look for the
minimum signal to fall to 0.0Hz. If the signal falls to 0.0Hz, this indicates that there is a problem
with the sensor.
Coolant Sensor
A coolant sensor is a thermistor that reads in voltage. Coolant sensors normally start at a high
voltage with the engine cold and as the engine warms up the voltage drops.
In the screen capture above you can see that the voltage starts high then drops as the instructor
turns the knob on the demonstration board simulating the engine warming up over time. Also
note that there are two distinct downward spikes in the waveform indicating a fault.
