How To: Remove TCS From a Trionic 5.2 Saab 9000
Contact Me | Image Gallery



  • Before You Get Started:
This guide applies to manual trans American market cars only.  Changes will need to be made for other models but the process will still work.  A/C will require more wiring mods to work properly.  I'll probably update the guide to include these changes as summer gets close.  I don’t know what affect this will have on ABS.  My car had a bad wheel speed sensor so ABS was already out.   I don't care enough to fix it to see what affect it had.  Also, you will lose cruise control completely with little hope of reviving it short of swapping out the entire system from a non-TCS car.

***Finally, I AM NOT AN EXPERT.  I did my best to follow the wiring diagrams and information at my disposal to put together a way to delete TCS/ETS.  There may be parts of this guide that are unnecessary or easier ways of doing things.  PROCEED AT YOUR OWN RISK!!!  

  • What You'll Need:
9000 Specific Parts:
You will need five (actually six) 9000 specific parts.
  • Trionic 5.2 ECU (re flashed to non-TCS software)(P/N- ANY)
    This will probably be the hardest part to source.  You can DIY or find someone on one of the Saab forums to do it for you.  Won’t go into details on how to re flash in this guide. It may be possible to use a t5.5 ECU with some software modifications.  I'm gonna test it and will update the guide if they'll work in place of the t5.2 ECU.
  • Manual Throttle Body (P/N- New Style: 78 71 437 or Old Style: 91 16 724)
    The throttle parts varied form year to year but anything off a 91+ 4cyl car should work.  94-98 is new style and 91-93 is old style.  Just get everything off the same car otherwise you'll have to make sure your parts will work together.  Applies for next two items.
  • Standard Throttle Cable(P/N- New Style: 45 25 515 or Old Style: 41 61 907)
    Throttle cable P/Ns are different for auto trans cars.
  • Standard Throttle Pedal (P/N- 89 67 903)
    Should be the same part on all 90+ cars but the part I used from a 96 had clearance issues.  More on how I made it work later on but be aware of this.
  • Two rubber hoses for AIC to throttle body (P/N- 30 54 5466 and 91 28 703).
Other Stuff:
These parts can be sourced from any 9000 or NG900 with t5.5.
  • Throttle Position Sensor (P/N- 88 57 195)
    This exact p/n came off the 94-95 9000 turbo, 94-95 NG900 turbo, 91-94 c900 non-turbo.  You should be able to use any sensor from a 94-98 9000 or 900 turbo as long as it has three electrical pins.
  • Air Idle Control Valve (P/N- 87 87 996)
    Not really sure what car these came on but you can use any AIC off a 94+ 9000 turbo.  You can also get the part off the a NG900 turbo.   Should have two electrical pins and a straight through design like the one pictured.
  • Coolant Sensor  (P/N- 87 87 996)
    This is the standard coolant sensor for all pre 93 9000s and all c900s made after 85.  Don't be a cheap ass; this is the one part I recommend you buy new.
  • Wiring Connectors
    Wiring connectors for the TPS, coolant sensor, and AIC.  You'll also need five pins that connect into the ECU.  See the "Building Your Wiring Harness" section for more info.

  • Building the Wire Harness:
There are a total of three connectors that need to be wired into your existing engine wire harness.  The easiest way to do this is to build a separate "piggy back" harness.  In the end, it will consist of three wires for the TPS, two wires for the AIC, two wires for the coolant sensor, and one wire for the coolant sensor reference.  For those of you who are bad at math, that’s eight wires total.  Here's where the wires are going:
Wiring Information:
TPS:
PIN 1 (Green/Red) to ECU PIN 42
PIN 2 (Black/White) to Intake manifold ground
PIN 3 (Gray) to ECU PIN 45
AIC:
PIN 1 (Red/Blue) to ECU PIN 49
PIN 2 (Blue/White) to Switched power source
Coolant Sensor:
PIN 1 (Yellow) to ECU PIN 68
PIN 2 (Black) to Intake manifold ground
Coolant Sensor Reference:
ECU PIN 66 (Black) to Intake manifold ground
NOTE: You don't need to know this info yet, but I'm adding it.

You can build the harness from scratch by sourcing the three connectors and five ECU PINs then adding wire.  

However, for most people there's a better way.  You'll need to find a 9000 or 900 t5.5 car with a complete engine wiring harness.  These cars are still pretty common at self-service junkyards so check around.  

First, you need to remove the engine harness from the car which isn’t bad.  Just remove connectors in the engine bay until the whole thing is free.  Then, at the ECU, there are few large connectors (one going into the ECU, the others will have wires going into the car; varies year to year).  Remove those and pull the harness off the car.  Unravel all the tape to expose the wires. 

After that, just follow the TPS, AIC, and coolant sensor connector wires back to the ECU/ grounding point/ switched power source(for AIC).  You also need to get the coolant ground reference which is PIN 66 of the ECU connector.


Some of the newer cars have a different connector for the coolant sensor.  If you get one of these harnesses, grab one of the fuel injector connectors.  They're the same as the older style coolant connector.

Cut the wires at the ground point and switched power then follow the other wires to the ECU.  Remove the wires for the ECU including the
all-important PIN connector.  How is this done you ask?  Well, some nice person created a write-up to help us to just that.
 
CLICK HERE TO VIEW PIN REMOVAL GUIDE.  

Do this all at the junkyard so you don't have to pay for the entire harness.


When you’re finished, all the wires will be the perfect length with no need to solder or connect things together.  

You should end up with something like you see here.  Avoid the temptation to tape everything up right now.  Wait until its on the car.

Alternative Method: You can use the existing wiring from TCS to wire in the connectors.  Just move the PINs around at the ECU connector
and splice in the TPS and AIC connectors.  The disadvantage is your car will be harder put back to stock if ever wanted.


 

  • Lets get started-
You've got all the parts together and realized everything’s been pretty easy so far.  Well, this whole process is easy but there's one fiddly part.

I like to get the BS out of the way first so here we go.  The first thing you'll need to do is remove the ETS throttle pedal.

 In order to do this, you must first remove the throttle potentiometer, which is another part of the ETS system.  The throttle potentiometer is held on to the car via a stud with a E-clip.  I know, weird but that’s how they did it.  You'll need to use a flat blade screw driver to work the clip off then the throttle potentiometer just slides off.  Well, its slides off with a little persuasion.  Once it's loose, disconnect the electrical connector, and pull it out.


With the potentiometer out of the way, you can access the throttle pedal.  The ETS pedal's held into a metal bracket using two plastic bushings.  The bushings must be pressed out before the pedal will pull free.  This can be difficult with the limited access and I ended up breaking one of the plastic bushings (see image) getting it out. 

Once the pedal’s free, reach up and push the plastic bushing holding the throttle cable to the pedal out of its seat and the cable should slide free. 

The first thing you'll notice is the ETS pedal mounts differently than the standard pedal.


The good news is, your car comes ready to accept either pedal from the factory.  If you look below the mounting point for the ETS pedal, you'll see a small hole and a larger hole pressed into the sheet metal.  If you feel back into the carpet, there's find another small hole.  That is where the new pedal will mount with two 5mm hex screws.  


                                                       NOTE: Even though the Saab EPC lists the standard throttle pedal as being the same for all 9000's, I had some clearance issues.  Basically, there’s an L shaped stop on the pedal which was catching on the bracket for the old ETS pedal.  My solution was to break the stop off and re-weld it about 1/4 of an inch down and over to make clearance. Don't know why it happened but be prepared for it.  Chances are, you won’t have an issue.


NOTE: It may be possible to use the old tcs pedal with the standard throttle body and cable.  You need to leave the pedal potentiometer in place too because it provides the recoil action for the tcs pedal.
 This would save a lot of hassle if it works but I didn't realize/ think of it until it was too late to test.

If you got the throttle pedal installed then give yourself a pat on the back.  The hard part's behind done and you're soon to have a non-TCS car.


The next step is to remove the throttle cable.  If you followed the last step, it should no longer be connected to the pedal inside the car.  Personally, I removed the brake reservoir to make clearance to remove the cable.  In retrospect, that was probably not necessary and as long as you can get some pliers on the metal part and pull straight back it will work.  If you don’t pull straight back, the throttle cable will break where it enters the firewall.


A close up of the ETS throttle cable entering the firewall.

Pull straight back.
 
Once the old cable's out press the new one into the rubber bushing.  You can use some soapy water to lube the throttle cable and bushing.  

Go back under the dash and attach the cable to the pedal you just installed.

Next up is the throttle body.  It's held on by three 13mm nuts.  The AIC hose barb on the manual throttle body will get in the way when you reinstall one of the nuts.  Mine was kind of loose so I removed the barb, tightened the nut, then JB Welded it back into place.  Otherwise, you'll need a small 1/4-inch ratchet and 13mm socket to tighten the nut.

Once the manual throttle body is on you can attach the throttle linkage.  Then install the AIC with the arrow facing up.  There's a stud that's suppose to hold the AIC to the intake manifold.  Although the hole is there, the stud isn't and will need to be added.  I didn't have it so my AIC is just held up by the hoses.

The coolant sensor can be reached from the top in-between the intake runners.  The wrench size you need is 19mm.

At this point, you can test the throttle assembly and adjust if necessary.  The car is a few electrical changes away from being done...

NOTE: I found a metal bracket inside my intake manifold that wasn’t there on the newer cars.  I think Saab called it an air shield.  I removed it thinking it was related to the ETS TB, but looking at the EPC, it’s supposed to be there on non-TCS cars too.

  • Add the wiring harness-
This part is self explanatory.  Just plug in the connectors and run the wiring.  The three ground wires goto the grounding point on the intake manifold.  The switched power can come from any of the fuel injectors or for a more professional approach- tap the switched power from the large blue/red wire running through the round connector on the false firewall (see picture).  Next comes the most important part of the whole process.

You have to add the PINs from your harness into the ECU connector already in the car.  You need to make sure all the wires are going to their EXACT spots and that the little PINS fully seat into the large ECU connector.  I can't stress how important this part is.  TAKE YOUR TIME AND DO IT RIGHT THE FIRST TIME!  
The PIN must be aligned properly in it's spot then it slides in pretty easily.  I used a pair of tweezers to push the PINs in.
  
If you end up with a non-running car then you probably messed up here or sourced the wrong parts. Again, I would wait to tape up the harness until after the car's been tested.  The wires will be easier to trace/diagnose if they're separated.  Here's where everything goes one more time:


Wiring Information:
TPS:
PIN 1 (Green/Red) to ECU PIN 42
PIN 2 (Black/White) to Intake manifold ground
PIN 3 (Gray) to ECU PIN 45
AIC:
PIN 1 (Red/Blue) to ECU PIN 49
PIN 2 (Blue/White) to Switched power source
Coolant Sensor:
PIN 1 (Yellow) to ECU PIN 68
PIN 2 (Black) to Intake manifold ground
Coolant Sensor Reference:
ECU PIN 66 (Black) to Intake manifold ground
NOTE: Don't rely on the colors to do your wiring.  Wire color may vary depending on the year car your wiring comes from.
CLICK HERE TO VIEW THE T5.2  WIRING DIAGRAM
 
Once you're satisfied with the wiring, install the non-TCS ECU.  Don't forget to add the ground strap.



Grounding point on intake manifold (between cyl 3 & 4)

  • Finishing up-
I lied earlier, there's more!  First, you need to disconnect the ETS computer under the drivers seat.  Also, you'll want to tie up the old wiring from the ETS system so it doesn't get snagged or melted.  

Next, reroute the vacuum hoses for a non-TCS car.  You need a hose going to the BPV and one going into the car for the boost gauge. The lines for the FPR, Map Sensor, and PCV shouldn't need to be changed.

The two vacuum switches on the false firewall and drivers side inner fender can be removed.  Remove any left over ETS hoses and cap any open intake nipples.


                                                        This isn't my image; just found it on the net.  It's of an older car but this is what your going for.

Once all that is done, start up the car and give it some revs.  If every thing's okay then chances are you did it right.  Tape up your wire harness and enjoy.

Going back to TCS/ETS is reversal of this procedure.

AIC: Air Idle Control Valve
C900: Classic 900 -93
ECU: Engine Control Unit (located in left hand side of the plastic aquarium in between the firewall and false firewall)
EPC: Saab Electronic Parts Catalog

ETS: Electronic Throttle System (ETS/TCS are closely related and the terms are used somewhat interchangeably throughout the guide)
NG900: New Generation 900 94-

P/N: Part Number
T5.2: Trionic 5.2
T5.5: Trionic 5.5
TCS: Traction Control System
TPS: Throttle Position Sensor