speedometer cruise not working

was able to remove the EGR solonoid to test with ohmmeter & tested ok.
(Saturn 94 1.9) The cannister purge is unassesable & will have to wait for
a mechanic.
Here is more background with the symptoms:
Speedometer, odometer, cruise does not work. (although cruise light comes
on)
Prior to this happening, the seat belts went bezerk, back & forth while
driving, talked to a Saturn mechanic, & said they get a lot of that where
people leave drinks on the center console, & liquid gets in there & may
short out a module.
I checked for liquid spill on top & found none, didn't disassemble
console, belts are ok now, dont know if it was related prior to the
speedometer not working.
The check engine light stays on, seat belt light flickers.
Prior to this I shot some WD 40 in the ignition key column because the key
was sticking.
So, after eliminating the EGR solonoid as the defect I have 3
possiblities:
1. Cannister purge solonoid $33
2. PCM $400
3. VSS (speed sensor) $22
Any thoughts or opinions (furthur testing) is welcome,
Thanks Bob

 

The speedo, odo, cruise and passive restraint module all rely on the "speed
out" signal from the PCM (pin A2). The seat belt light gets it's signal from
the passive restraint module. My guess is the speed out signal from the PCM
is messed up. It could be a bad VSS ( vehicle speed sensor ) or wiring ,
PCM, something shorting the signal like bad passive restraint module or
wiring. An o'scope on PCM pin A2 or any of the three DK GRN - WHT wires on a
4 pin connector (the 4th pin has a ORN wire) on the Instrument Panel
Junction Block ( Saturn's name for the fuse panel inside on the passengers
side) should tell you if you have that signal. I don't know what it should
look like but my guess that it is a square wave that varies in frequency or
pulse width as the speed of the vehicle changes. I haven't seen prior posts
but I'm guessing that if your checking the EGR and Canister purge solenoids
that you also have a Quad driver error code set in the PCM - are there any
other codes? A bad VSS should show up as a code (24). A shorted "speed out"
from the PCM may give quad driver fault (26) if the quad driver handles the
"speed out" signal. I'm not sure if it does but the EGR and Canister purge
only account for two of the 4 quad driver outputs. Hope this helps.