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H03011 - How do I adjust the Vehicle Speed Sensor pulse rate?
The signal pulses coming from the vehicle speed sensor are generated for use by the
vehicle’s computer, engine/transmission control, fuel management, ABS brakes, etc. The
pulse rate can vary from 4,000 to in excess of 100,000 pulses per mile. The Modular
Distance Sensor (MDS) will condition and amplify these pulses for use by the RAC. Since
the higher pulse rates are not required for accurate distance measurements, the MDS
incorporates a divider circuit to reduce the pulse rate. This is done by adjusting the rotary
switch on the front of the MDS, as shown here.
H03011 - How do I adjust the Vehicle Speed Sensor pulse rate?
The signal pulses coming from the vehicle speed sensor are generated for use by the
vehicle’s computer, engine/transmission control, fuel management, ABS brakes, etc. The
pulse rate can vary from 4,000 to in excess of 100,000 pulses per mile. The Modular
Distance Sensor (MDS) will condition and amplify these pulses for use by the RAC. Since
the higher pulse rates are not required for accurate distance measurements, the MDS
incorporates a divider circuit to reduce the pulse rate. This is done by adjusting the rotary
switch on the front of the MDS, as shown here.
Although your particular vehicle may vary, generally Chrysler and Ford vehicles use a 4 to 1 ratio (position 4 on the switch) while General Motors
vehicles use a 16 to 1 ratio (position 16 on the switch). To adjust the ratio, use
a small screwdriver to rotate the switch until the slot in the switch points to the desired ratio. Note that when the switch is turned counter-clockwise until it
stops, it is at the 1 to 1 ratio.
The adjustments go from 1 to 1 (1 pulse into the sensor, 1 pulse out) through 64 to 1 (64 pulses into the sensor, 1 pulse out). You may need to adjust
the ratio again based on the results of the calibration procedure. Any time you change the pulse ratio, you will need to re-calibrate the DMI.
vehicles use a 16 to 1 ratio (position 16 on the switch). To adjust the ratio, use
a small screwdriver to rotate the switch until the slot in the switch points to the desired ratio. Note that when the switch is turned counter-clockwise until it
stops, it is at the 1 to 1 ratio.
The adjustments go from 1 to 1 (1 pulse into the sensor, 1 pulse out) through 64 to 1 (64 pulses into the sensor, 1 pulse out). You may need to adjust
the ratio again based on the results of the calibration procedure. Any time you change the pulse ratio, you will need to re-calibrate the DMI.
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