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!!!
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:
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.
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.
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.
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