[Keyz]

Thanks for your reply @Jim Mesthene you're right, I will check up the harness and connector by testing the pump at ECU plug.

Thanks too for your reply @a9548925559, I've found the eBay annonce for the switch pressostat :

• SAAB 8994071

The ABS system used on 1988-1993 SAAB 9000 and 1990-1994 Classic 900 operates at pressures near to 2000 psi. The accumulator stores enough brake fluid, under pressure, to allow about 12 power assisted stops before the electric pump must run to bring the pressure back up.
IF YOU HAVE NO POWER ASSIST (BRAKE PEDAL TAKES A LOT OF EFFORT TO STOP THE CAR):
Have someone familiar with automotive electrical diagnostic procedures do the following checks: quick diag no or weak assist on SAAB ABS Mark 2 cars. Find the ABS fuse and relay box, then check the fuses (all 3). Check for power at pump relay large red wire. If no power, find out why. If you have power, jump large red to the large yellow wire. The pump should run, if not check the pump ground. (at the master cylinder assembly.) If the pump runs, disconnect the jumper, pump brake pedal until hard, turn on the ignition key (engine off) and check for 12 V at double blue lead from pump relay, if 12V replace pressure switch, it should have been grounded, assuming a hard brake pedal. If 0 volts try a new relay. Once you get the pump running check accumulator and the rest of the system.​

video on how the system works:

 

[Keyz]

@AUSSIE900 could you get a pic of the two torx screws which give access to the winding of pump, please? I don't see them.

 

[Keyz]

This is pin 2 of ABS control unit that triggers ABS pump. I can't see pins numbers, because there's no screws to pull out the ABS ECU cover out...

 

[AUSSIE900]

TWO T25 screws to seperate the winding off the pump housing
BUT I doubt your pump electrics have failed , I connected 12v to the 2 pin connector seen in the next picture to test that the pump ran . Bench test.
I did this for giggles and your guidance , but with no care re polarity as its a spare that is unlikely to be ever used , I am no expert so dont know if any impications of reversing the polarity , It was purely to hear if the pump ran , which it did , IN the picture below it is the 2 pin connector in the middle of the photo . Nearest to the accumulator.

 

[Keyz]

Thanks @AUSSIE900, I removed the coolant reservoir to gain access to the torx head screws.

 

[Keyz]

I have an other blue embassy 900, on which I can bench test ABS pump.

 

[Keyz]

I've bench tested ABS pump and wiring on the blue embassy 900.

-A jumper wire between ABS pump Relay pins 30 and 87, turns on the pump.
-A 12V battery connected on pins 2 and 14 of ABS ECU's socket turns on the pump (pins numbers are printed on the ABS ECU's socket).

-Two wires connected on the two pins you showed on first pic, make a clicking sound, but the ABS pump doesn't turn on...

 

[Keyz]

Components 6 is ABS pump, and 7 is ABS pressure switch.

 

[Keyz]

This guy explains how to pull out error codes from ABS ECU, it's the same procedure as pulling error codes out if the Injection ECU.
I'll try if this works.

 

[Keyz]

On the scarab green 900 (with no buzzing sound from the pump), neither the jumper wire on pump relay, nor direct feed from 12V battery on pins #2 and #14 do turn on pump (just make pump relay clicking).

Direct feed from a 12V battery to the two ABS pump pins doesn't turn on the pump motor. And putting a voltmeter on the other side of the plug display 11.8V, meaning power is going to the plug.
So I'm pretty sure pump motor is the culprit.

I viewed a video which a guy explains how to test ABS pump windings.

As I mentioned below, I think that ABS pump is seized up.

 

[Keyz]

ABS pump has been changed, and it works. Now, problem is that it doesn't stop, it keeps turning and turning continously...

ABS brake accumulator is brand new and pressurize well on my other Saab. What could prevent from stopping? The pressostat? The old pump burned because it was turning continously... over and over...

 

[jvanabra]

Failed pressure switch would be my guess.

 

[Keyz]

Do a long 36mm socket could unscrew this ABS pressure switch?

 

[Keyz]

"1-2-2-2" ABS fault code blinks on the dashboard ABS light, when I pull out faults codes with the diagnostic socket.
This points towards "ABS Main Valve", but this is not relevant... It clicks when I put direct power on it, I'll try to test its resistance value.

No leaks from the brake system, since the pump is now working, I'll try a complete flush!
Can air bubbles prevent the pump from pressurizing the brake system ?

 

[jvanabra]

I would say clicking is not a valid test. That just means the solenoid is doing something. It doesn't necessarily mean the valve itself is working.

 

[Keyz]

Fault code for faulty ABS pressure switch (pressostat) is

"1-2-2-2"