940 L4-2.3L SOHC VIN 88 B230F (1992)
Speedometer Head: Description and Operation
The speedometer is electric and, in addition to showing the speed, also has an odometer and a trip meter as well as an output for speed signal.
An inductive sensor transmits signals to the speedometer. The number of pulses per kilometer is 25,793 and corresponds to a tire circumference of
1.861 meters (73.27 in).
The speedometer has two short-proof outputs for the VSS signal, one with the same frequency as the input signal, 48 pulses/rev. and one with a
frequency corresponding to 1/4 of the input signal, 12 pulses/rev.
The frequency of the VSS signal's outputs is proportional to the frequency of the input signal and is used for the following systems:
12-pole output:
D1 system
Fuel system
Cruise control
48-pole output:
Electronically controlled automatic gearbox
It is important that accessories should be connected to the 12-pulse signal. Wrong connection of accessories can cause the speedometer to fail and wrong
codes to appear in the brake, ignition or automatic transmission control systems.
Without current, the speedometer needle should rest max. two divisions below zero.
Needle flutter above 20 km/h (12.5 mph) is not acceptable.
At speeds below 20 km/h (12.5 mph) flutter of max. one division is acceptable.
