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hello,new here and ned HELP!!!!

590 views 9 replies 5 participants last post by  99Saabnut 
#1 ·
HI, I am new to this site and also to Saab. I have always admired them, but never owned one. Now I have one, it is a 95 900S 2.3l 5 speed. Well even though it is low on milage and in nice shape, it has its fair share of problems. I need help with the speedometer. I noticed it is about 20 MPH off, it reads lower than what I am actully going.I was wondering if it could be the sensor on the transmission, and if so where is it located.

P.S.- I also need literature on this, (owners manual, and service manuals)

Any help would be greatly appreciated........



Craig
 
#3 ·
#4 ·
GaryG said:
Welcome to SaabCentral. The speed sensor is on the rear axel and you should have tires that match the OEM profile 195-60-15. If you have a different size you can calculate the speed difference at this site.

http://www.miata.net/garage/tirecalc.html

If the difference doesn't match what you calculate then there is something off with the sensors or the electronics.

so are you saying that the sensor is in the rear even though it is a front wheel drive? Also the tires are of the correct size. thanks
 
#5 ·
Front drive has nothing to do with this, Saab uses one of the ABS(anti-lock brake system) sensors(a generator of a sort) ....

Craig, how were you able to definitely determine that the speedometer is off by 20% ?
 
#6 ·
Ok, now that you say that it uses an abs sensor for the sensing, it makes sense. One of my front sensors is bad, which might be throwing off the system. I noticed that it is off by 20MPH by following my wife at various speeds, and came up w/ the results. It is also that when I am going less than 20mph it doesn't even move the needle. once I hit 25mph it reads 5mph there for it is about 20 mph off. I will go over the abs electrical system w/ a fine tooth comb and check everything. thanks craig
 
#7 ·
The speed signal is derived from the "front right wheel" (WIS), and the signal goes from the ABS to the ECU (Trionic or Motronic, same signal, same wheel).

edit:

I believe the sensors on the front wheels can be cleaned, on the rear, the wheel sensors are part of the hub.
 
#8 ·
A friend of mine had a similar issue: His ABS light was on intermittently, and whenever the light came on his Speedometer would drop to zero. In his case it was the left rear ABS sensor with a bad connection.

I think the system uses more than one sensor; otherwise it would read weirdly every time you go around a corner... Inside wheels would be moving faster than outside, etc. It likely averages the inputs or something.
 
#9 ·
99Saabnut said:
A friend of mine had a similar issue: His ABS light was on intermittently, and whenever the light came on his Speedometer would drop to zero. In his case it was the left rear ABS sensor with a bad connection.

I think the system uses more than one sensor; otherwise it would read weirdly every time you go around a corner... Inside wheels would be moving faster than outside, etc. It likely averages the inputs or something.
I think I would have to agree w/ you on this one, because if it was teh right front wheel only, mine wouldn't work at all because my wire is ripped off. I will order a new one from eeuroparts.com. I chacked all my local supply places and they can't get anything other than normal maintnance stuff. Thanks again, this was one of the fastest answers I have ever recieved from a message board. Thanks again. Craig
 
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