1994 Q45 TSC PUMP

[xkss62]

I have a 94 Q45 that I am getting back in shape after only a little use for the past few years. I have had the Slip and TCS Off light on for a while. I have been through the past threads and my first problem was the Secondary Throttle Sensor. After installing it the lights when off. Now that the sensor is fixed my TCS Pump is making a lot of noise. I start the car, no lights and the pump comes on and runs for 20-30 seconds and shuts off and the lights come back on. If I crack the bleed valve on the Actuator the pump is much quieter as the fluid cycles back into the reservoir. I removed the pump and cleaned the reservoir and poured clean break fluid in the pump inlet while jumping the pump and it seems to pump OK.
So the question, do I need a new pump or is there something in maybe the Actuator that is causing the pump pressure to be to high and make the buzzing/knocking sound.
My local salvage yard has both the Pump and Actuator on a car I can pull, but I only want to buy the part I need.
Is there any way to tell which is the bad part?

Thanks in advance

[N/A Q45]

Did you check the code on the tcs unit in the trunk?

The led light will flash the number of times which corresponds to the malfunction.

[xkss62]

TCS flashes 19

[N/A Q45]

Did you check the relay, they go bad and stick, I actually cut mine open and cleaned it problem solved-

[xkss62]

releys are fine And I did swap them out to test. The pump was not working until the STP sensor was replaced. The pump runs but makes alot of noise then shuts off and I get the fault lights.

[elwesso]

More commonly the TCS actuators (under the hood with the fluid res) fail. I've never heard of a TCS pump failing. The TCS actuator failures aren't horribly common, but they're getting more common as time goes on. Normally when the TCS actuators fail is they make a buzzing noise for about 30 seconds, and then the lights come on.

I would recommend you replace the TCS actuator. Usually finding a used part is a good bet since they don't fail super often. Replacement isn't really bad, be sure you have some flare wrenches to get the brake lines off (don't use open end wrenches, you'll round the flare nut).. You'll have to take the inner fender liner off to get to a couple bolts inside there, but otherwise it's simple.