speedometer/odometer not working

[spider1604]

The speedometer and odometer on my 94 SL2 have quit. Are they operated in the old fashioned way with a cable or is there some electronic thing involved also? The digits just roll up like in older cars but you never know about these things. If in fact it's a cable, does it attach to the transmission?

Thanks.

[sierrap615]

its electronic, there is a VSS in the transmisson. do you have a SES light to? i would imagine the PCM would go in to some sort of back-up mode if it detected a bad VSS. if there is no SES light, and assuming it is not in any sort of back up mode, you should be able to do a quick test of the VSS by the rev. limiter. at a dead stop the RPM should not go past 4000. while moving, the RPMs should be able to go above 4000. if the rev limiter works fine, the gauge cluster may be your problem. do you own a multimeter?

[spider1604]

Whoa. What's a VSS, SES, PCM? At least I do know what a multimeter is and own 2.

[sierrap615]

VSS- Vehicle speed sensor
SES- Service engine soon(you know, the light of death)
PCM- Powertrain control module(the computer that basicly controls the engine)

[just_in_the_sea]

Got the same problem with my '92 SC.... Tackometer and speedometer work fine but the odometer is just stuck at 200377 miles. I pulled the cluster out of there to have a look thinking maybe a loose connection (since the fuel guage bounces between 0 and actual) but spraying electrical contact cleaner on the plugin wire strips did no help for either.

I just tried your rev. limiter test (cool!) and it seems to work although it makes an awful crunchy noise as it does "it's thing" just above 4K RPM. What's the deal? Is it mechanical... or supposed to clip the RPM electronically?

I've a very intermittent problem wear the idle runs up to near 4000 RPM too... I wonder if it's related. thanks a bunch for any and all info!!

[bomexsaturn]

My 1994 Saturn SC2 stopped working at 222022 miles, but it started working again about 30 miles later, Saturns are weird, but quick and reliable.

[sierrap615]

Originally Posted by bomexsaturn

Saturns are weird, but quick and reliable.

i couldn't have said it better myself

Originally Posted by just_in_the_sea

I just tried your rev. limiter test (cool!) and it seems to work although it makes an awful crunchy noise as it does "it's thing" just above 4K RPM. What's the deal? Is it mechanical... or supposed to clip the RPM electronically?

I've a very intermittent problem wear the idle runs up to near 4000 RPM too... I wonder if it's related. thanks a bunch for any and all info!!

what the PCM does is cut the fuel injectors just as it goes above 4K, as soon as it falls back to 4K they start shooting again. since the difference of the staying below the limit and going above it is basicly nothing, the limiter will cycle pretty fast (maybe once a second?), which causes that "crunchy" noise ( it sounds to me more like a old 70s muscle car revving to me, its not a really good thing to do).

as for the idle, a bad ECTS design (electric coolant temp sensor) and carbon build-up in the EGR (exhaust gas recurulation:SP?) are common causes for high idle on early saturns. fix: replace the ECTS with a new redesigned one and take off the EGR and clean it out. another possibity is dirty fuel injectors.

[jakro1972]

I purchased a '97 Saturn SL2 that the speedo and odometer quit about 80 miles ago, any ideas? I checked my connections behind the cluster, all other gauges work. I disconnected the VSS from the transmission and took it for a drive. It set a service engine soon code and I could feel a difference in the shift quality. I assume the VSS is working. My cruise seems to work too. Does anyone know how to check the signal from the VSS to and from the PCM? Also, the engine takes longer to start when hot versus when cold! Put new spark plugs and air filter in, no noticeable remedy.

Thanks

[sierrap615]

see if you can roll the numbers by hand, then bench test the stepper motor. no start while hot in saturn is commonly a bad CPS

[Velez866]

Sierra you know your stuff... I have similar problem. I replaced my VSS and PCM; but no change. I'm having problems trying to check continuity of VSS wires to the PCM. Using Haynes book + mutimeter... In addition to no speed/odometer reading; trannie feels like its stuck in 3rd.... Any advise???

[sierrap615]

i myself prefer to use an osilioscope to test these type of sensors, but thats far from an everyday tool(anybody have one they want to sell cheap?)

what year? any SES light?

the automatic trans uses the VSS to help decide shift points, possibly causing the stuck in 3rd feeling.

if there is a SES light -
in haynes, page 6-14 step 41. do this check, be sure you are getting the 10 volts. also the VSS should have a resistence around 700-900ohms

if no SES light
double check for a blown out SES bulb(it should come on for a second at start-up), if its good tell me and will go from there

[pdoxey]

the odometer on my 93 SC2 stopped working. I thought it may have been the odometer gear, so I took it apart. The gear was intact, so I lubed the moving parts connected to the stepper motor as well as the gear and worm gear with silicone grease. Works fine now.

[spider1604]

Were these gears in the instrument cluster or on the cable?

Originally Posted by pdoxey

the odometer on my 93 SC2 stopped working. I thought it may have been the odometer gear, so I took it apart. The gear was intact, so I lubed the moving parts connected to the stepper motor as well as the gear and worm gear with silicone grease. Works fine now.

[sierrap615]

they are inside the cluster, but they only affect the odometer, not the speedometer

[pdoxey]

That's correct. There is no cable at all. It's an electronic feed to the instrument panel. There is a small stepper motor that turns the gear that then turns the odometer tumblers.