P0705 transmission code on Saab 9-3 SE

Question

This is a Saab 9-3.

Transmission code P0705 for "Transmission Range Sensor A Circuit (PRNDL Input)" has come on twice so far when the car turns on.

It really screws with the gear changes:

• The first time it popped up, the gear selector on the dash would show that only 1st Gear is selected, no matter what I do with the actual shifter.

• Second time it did correctly show that "D" was selected, however the check transmission light came on and it didn't sound or feel like it was switching out of 1st gear.

• Third time it turned on while driving. Was slowing down to a stop and the light came on. Tried going again but it again sounded like it was stuck on an incorrect gear. I don't actually think that it was stuck on first gear this time because if it was, I think that it would be pulling harder than it was. the RPMs went up and up but the car would barely move very slowly.

• Also, when the code is cleared, the car shuts off and when turned back on, it runs fine until the light turns on again.

So my question is, how would I go about pin pointing what exactly is at fault here? I'm assuming I have to whip out the old multimeter and check some sensors?

Answer 1

The code is actually telling you exactly what is wrong. The Neutral Safety Switch (Range Switch) is not functioning correctly. This can be rebuilt or replaced. It, as all Saab parts are, is very expensive to replace.

If you have the basic tools needed to get to it (on the transmission under the battery tray). You can remove it and take it apart, the issue will likely be apparent or it will be broken internally.

The steps should be something like (mine was a 9-5):

1. Remove battery and battery tray.
2. Remove Auto trans fill tube (clean base of tube first so junk does not fall into tube hole in transmission housing).
3. Cover the transmission tube hole with some tape or plug it with a rag.
4. Unbolt any hose clamps so you can move the hoses to get to the switch.
5. Remove nut that hold shift selector cable plate onto the NSS and lift shift selector cable plate off NSS.
6. Remove nut below shift plate along with retainer washer and rubber washer.
7. Remove fasteners that hold the switch in place and remove switch (it snaps in so you may have to pry).
8. There should be locking electrical connectors you have to remove, be careful as they are plastic and break easy.
9. You may have to cut some zip-ties etc, but you should have the switch free at this point.

From there, Google is your friend or drop the $200-300 for a new one. This is a common enough issue that you will find forum posts and videos for it.

Answer 2

I'm no Saab expert (My only vice is a 2005 92 Aero stick which is actually a Subaru WRX) . . . but I suspect from a bit of research the "Neutral Safety Switch" is at fault.

This is a lot more than a yes/no switch - it's a complex system of copper strips and a wiper all immersed in grease, which hardens over time and prevents proper contact for one or more of the important signals. The ECU goes crazy and can't tell what "gear" you want.

Not exactly one of Saab's finer designs...

A good test is to move the gear selector back and forth many times over the full travel, [foot on brake] with some [limited] violence, and see if that improves the situation. If it does, or probably even if it doesn't, the unit will either have to be replaced (rumored $350-ish for the part alone) or repaired.

I would take the unit apart, clean it up, and inspect it. Even if you can't fix it, half the work is done just getting it out and putting it back - which you'll have to do whether or not it's repairable.

Here's a link which describes the "repair" process. It's involved, but more of a time thing than a complexity thing. It will be quite rewarding if you decide to go the DIY route, and have spent nothing more than your time.

Basically, you'll have to remove stuff to get to it, dig it out, take it apart, clean out every trace of all the old nasty grease, polish the wiper strips and wiper with very fine sandpaper or fine steel wool, re-grease, reassemble, and reinstall. There's some great pictures in the link which well illustrate the challenge:

Saab Neutral Safety Switch Rehab

Best of luck. Please confirm your exact year/model, as this answer fits most but not all possible maladies.

The old Volvo/Saab Swede car joke goes: "Hey Johan, how do you like driving your your Volvo, the Swedish Buick?" "It's great, Sven. Much better than your Saab, the Swedish Fiat..."