Speedometer issue - ZR-1 Net Registry Forums

90zeearrone · 03-19-2024

Good evening All,

In preparation for the upcoming Canadian car season, I want to tackle an issue that I started having last year ( I know I shouldnt procrastinate on these things) but I was able to use an app for tracking my speed and total driving distance and honestly didnt drive the car as much as I wouldve liked to last year. Put less than 600km on it last season.

Im having an issue with my speedometer.
It shows 0km/hr and doesnt seem to work.
Sometimes on long highway drives it will kick in briefly (not all the time) and usually at speeds over 120km/hr.

Does this sound like a bad speed sensor?

Any tips or advice is greatly appreciated.

Thank you

tccrab · 03-20-2024

- The C4 Corvette with ZF6-S40 uses a pulse-signal-reference generated from the Vehicle Speed Sensor (VSS). The VSS, when equipped with a 15 tooth (T) drive gear (on output shaft) and 42T driven gear turning the VSS combined with a 3.45:1 differential ration, produces 4000 pulses per mile traveled. The VSIS is calibrated to 4000 pulses equaling one mile. When the differential (final drive) ratio changes, so does the pulses generated over each mile.
So is possible the VSS plug isn't making good connection or the internal drive gear is damaged or the ECM is fubar.

Crabs

03-19-2024	#1
90zeearrone Join Date: Aug 2020 Location: Canada Posts: 14	Speedometer issue Good evening All, In preparation for the upcoming Canadian car season, I want to tackle an issue that I started having last year ( I know I shouldnt procrastinate on these things) but I was able to use an app for tracking my speed and total driving distance and honestly didnt drive the car as much as I wouldve liked to last year. Put less than 600km on it last season. Im having an issue with my speedometer. It shows 0km/hr and doesnt seem to work. Sometimes on long highway drives it will kick in briefly (not all the time) and usually at speeds over 120km/hr. Does this sound like a bad speed sensor? Any tips or advice is greatly appreciated. Thank you Last edited by 90zeearrone; 03-19-2024 at 10:13 PM.

03-20-2024	#2
tccrab Join Date: Oct 2004 Location: Folsom CA Posts: 1,655	Re: Speedometer issue - The C4 Corvette with ZF6-S40 uses a pulse-signal-reference generated from the Vehicle Speed Sensor (VSS). The VSS, when equipped with a 15 tooth (T) drive gear (on output shaft) and 42T driven gear turning the VSS combined with a 3.45:1 differential ration, produces 4000 pulses per mile traveled. The VSIS is calibrated to 4000 pulses equaling one mile. When the differential (final drive) ratio changes, so does the pulses generated over each mile. So is possible the VSS plug isn't making good connection or the internal drive gear is damaged or the ECM is fubar. Crabs __________________ TomC '90ZR1 #792 Honorary Pirate [B]If it ain't FUN, you're doing something terribly WRONG. [/B]