ok i have an 86(700r4) iroc and after i got it back from a little accident about a year ago, i noticed the odometer didnt work, the speedometer does, just not the odometer. It has just started to bother me and i would like to fix it, also, my car started throughing the trouble code for the VSS. what should i do about this? thanks
is your's a VSS? not sure if '86's had VSS's.
sounds to me like you need to take your speedometer out and get it fixed/replaced, I suspect the speedo/odo are a unit/module, but I'm also waiting with abated breath to see what the experts say.
my factory 1990 Camaro Service Manual (8C-3) which addresses electronical speedometry says:
"The electric speedometer does not have a speedometer cable. The source of speed information is a small permanent magnet alternating current generator called a VSS, mounted on the transmission ... This generates an alternating current in the coil with a frequency that is proportional to the speed of the vehicle."
"At the speedometer, a solid state circuit uses the spped signal to regulate the distribution of current from the "GAGES" fuse in the fuse block to two electromagnetic coils ... The relative strength of the two magnetic fields determines the position of the magnet and accordingly, the position of the speedometer pointer."
"Pulses from the solid state circuit also are used to drive a small electric stepper motor. The stepper motor turns the numbered wheels of the ododmeter and the trip odometer....
"When a speedometer is replaced, the law requires the odometer reading of the replacement unit to be set to register the same mileage as the prior odometer. If the same mileage cannot be set, the law requires that the replaement odometer be set to zero and a label be installed on the driver's door frame to show the previous odometer reading and the date of the replacement."
chapter 9B-3 address the VSS Buffer:
"This device receives a signal from the vehicle speed sensor (PM generator) indicating the speed of the vehicle. This signal is then processed by the VSS buffer and supplied to the ECM, the cruise control module and the speedometer. The speed sensor buffer is used only on vehicles equipped with the L03 (VIN Code E) engines."
yada yada yada.
sounds to me like you need to take your speedometer out and get it fixed/replaced, I suspect the speedo/odo are a unit/module, but I'm also waiting with abated breath to see what the experts say.
my factory 1990 Camaro Service Manual (8C-3) which addresses electronical speedometry says:
"The electric speedometer does not have a speedometer cable. The source of speed information is a small permanent magnet alternating current generator called a VSS, mounted on the transmission ... This generates an alternating current in the coil with a frequency that is proportional to the speed of the vehicle."
"At the speedometer, a solid state circuit uses the spped signal to regulate the distribution of current from the "GAGES" fuse in the fuse block to two electromagnetic coils ... The relative strength of the two magnetic fields determines the position of the magnet and accordingly, the position of the speedometer pointer."
"Pulses from the solid state circuit also are used to drive a small electric stepper motor. The stepper motor turns the numbered wheels of the ododmeter and the trip odometer....
"When a speedometer is replaced, the law requires the odometer reading of the replacement unit to be set to register the same mileage as the prior odometer. If the same mileage cannot be set, the law requires that the replaement odometer be set to zero and a label be installed on the driver's door frame to show the previous odometer reading and the date of the replacement."
chapter 9B-3 address the VSS Buffer:
"This device receives a signal from the vehicle speed sensor (PM generator) indicating the speed of the vehicle. This signal is then processed by the VSS buffer and supplied to the ECM, the cruise control module and the speedometer. The speed sensor buffer is used only on vehicles equipped with the L03 (VIN Code E) engines."
yada yada yada.
JamesC
Moderator
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Apr 15, 2026
An 86 Camaro would have a mechanical speedo with the VSS located on the rear side of the cluster (small yellow box in one of the pics). Check the following link for repair:
https://www.thirdgen.org/techbb2/sho...hreadid=249244
JamesC
https://www.thirdgen.org/techbb2/sho...hreadid=249244
JamesC