Speedometer not working.

[rfEngineer]

I've a 98 Legacy Outback, 2.5L, manual trans. The speedometer suddenly stopped working. I pulled the cluster, removed the speedometer and bypassed the center-pin (ground) on the speedometers 5-pin connector. Still no indication on the meter. Since the most common cause of a Subaru speedometer failure was not the culprit I assume it must be either a bad VSS or the ECM. I went looking for the speed sensor and found three of them:eek:! The so-called experts have given me widely conflicting information about which one(s) provide the speedometer signal.

 

Enough background, here's my question. Which VSS provides data for the speedometer and where is it located? As an aside, what are the other VSS's used for? Any other tips for resolving this problem would also be appreciated.

[psu_lgt]

had the same problem last year on my 96 impreza. looked at everything i could think of. same issue finding out there were multiple VSS's. subaru dealerships were of no help. took the car to a family friend who rebuilds subarus. he replaced the wire harness in the cluster, and problem solved.

 

Good luck. Hope you are able to get it taken care of

[BAC5.2]

There aren't 3 speed sensors on the manual transmission... there is one. And it's attached to the passenger side of the transmission. The two sensors at the rear of the transmission are for neutral and reverse.

 

You can TRY replacing the speedo sensor in the transmission, but if that doesn't fix your problem you have two options.

 

Hook up a select monitor and see if the ECU is outputting a vehicle speed signal. This is pretty easy to do, and any scanner capable of live-data will tell you. Methinks it's not an ECU problem, because there is a speedometer MIL and you'd see that on the dash.

 

If the ECU DOES output a voltage for the speedometer, then the problem is in the harness between the ECU and the cluster. A multimeter will tell you if there is a break in any of the wires.

 

If the ECU DOESN'T output a voltage for the speedo, you can snake a lead directly to the output pins on the speedo sensor in the transmission. The sensor is just a hall-effect sensor and will produce a voltage. Just hook up a multimeter and drive a few mph to see if it outputs anything.

 

If the speedo sensor DOES output something, then the problem is in the wiring between the ECU and the speedo sensor. Again, not too difficult a check (since that wire is actually in sections, you can test each section).

 

If the speedo sensor DOESN'T output anything, then the problem could be in the sensor itself.

 

You can snag one from a junkyard or buy one at the dealer or an autoparts store. Replace the sensor and try again. Since you've ruled out the wiring and ECU, it should work just fine.

 

If it STILL doesn't work, then your options look grim. It's either the ECU (but, again, that would throw a MIL), or it's the speedo gear inside the transmission.

 

Unfortunately, the transmission must be removed and disassembled to replace that gear. Fortunately, the shafts don't actually have to be broken down, so a shop should only charge a few hours of labor if you pull the transmission out.

 

I'd suggest doing it yourself, but pulling a transmission apart is a big job not for the faint of heart. If you pull it out yourself, replacing that gear should cost you less than $250.

 

Kind of crappy, I know, but hopefully you'll sort things out.

[kennethknight]

hi i own a 1996 subaru legacy manual transmission where is the vss exactly located i tried to find it but cant.

[jppare]

Hi! i am reviving this old post because the explanation of BAC5.2 was really interesting.

 

In my case.... First of all, i have a Legacy gt 98 2.5 wagon MT. The car is running fine and the speedo is WORKING.

 

BUT! when i plug my OBD2 Reader, it tells me that the ecu is not receiving anything at all, and sometimes he receives some signal but erratic. Example:

 

If i drive 50km/h (shown on my speedo), the ecu will sometime receive the exact speed or nothing at all and sometimes... it changes every seconds, like 9 - 25 - 50 - 36 - 28 - 35 then 0. when i brake sometimes he gets signal back and see something and then back to nothing.

 

The weird thing is that, i dont have one check engine but 4! Since the VSS popped out i got other codes.

 

Got codes for:

 

- VSS (vehicle speed sensor #2), on manual trans there's only one sensor

- idle air control valve

- knock sensor (popped once)

- EGR valve

 

All this in one week... sometimes i need to fight with the car to keep it running. When the car doesn't see the speed and i press the clutch, the rpm dramatically drop really low and i need to press the gas pedal to help it keeping up. if check engine is on PLUS the car doesn't see the speed, the car stall automatically when i press the clutch, the idle control doesn't take the lead.With my reader i delete the codes after having them popped and restart the car, like this i never get in limp mode and then the car runs fine until the next code pops.

 

What could it be??!!!???

[Osei]

Can't find the exact post ( I know it was on USMB). There was a recurring issue because of loose screws on the back of the instrument cluster causing intermittent grounds and therefore results.

Was also a post re: a fix with a broken solder joint.

As far as the other issues. Clear and report on which ones return quickly.

IAC will probably need to be cleaned.

Make sure all the small tubes that go to and from the EGR are clear.

 

O.