wht89reatta Posted November 19, 2014 Share Posted November 19, 2014 Hello, today on my drive home from work the diagnostic center came up and said that I had low ABS pressure, the pedal still felt fine and it still stopped normally. When I got home and shut the car off I noticed the master cylinder pump was still running. Is this just an ABS pressure sensor issue or is there something more going on? Any help is appreciated.-Chris- Link to comment Share on other sites More sharing options...
DAVES89 Posted November 19, 2014 Share Posted November 19, 2014 Did your motor ever shut off? It sounds like a pressure switch to me. However if you try rotating the relay switches on the fire wall to be sure it isn't a relay issue. Link to comment Share on other sites More sharing options...
wht89reatta Posted November 19, 2014 Author Share Posted November 19, 2014 Motor is still running 2 hours later. I will go out right now and try the relays. Link to comment Share on other sites More sharing options...
wht89reatta Posted November 19, 2014 Author Share Posted November 19, 2014 So I just went out and checked the brake pump. The accumulator was extremely hot to the touch. So I unplugged the pump to let the whole thing cool down for a moment. I plugged it back in after about a minute and the motor was still running all the time. I unplugged it again. I went to get a couple of tools to check the relays. and when I plugged the pump back in it ran for about 15 seconds and then shut off. I will keep an eye on this in the next few days so as to give anyone else with a similar situation help in the future. Link to comment Share on other sites More sharing options...
Ronnie Posted November 19, 2014 Share Posted November 19, 2014 I suggest you replace the brake pump relay as a safety precaution to prevent burning up the pump. The contacts in it are probably burnt and sticking. It is cheap insurance for protecting the pump from damage. Link to comment Share on other sites More sharing options...
wht89reatta Posted November 19, 2014 Author Share Posted November 19, 2014 Good idea. Will do, thanks again. Link to comment Share on other sites More sharing options...
Barney Eaton Posted November 19, 2014 Share Posted November 19, 2014 (edited) Pull the connector on the pressure switch... it is next to the motor and usually has a green tint to the alumumin housing. If the connector is damp, it could be the pressure switch.Below is a greatly simplified schematic of the relay, pressure sw, and pump. Note that the pump will not work if the relay is bad OR if the pressure switch is bad and not energizing the relay.The pressure switch will not work if the 5 amp fuse is blown.You can test the motor by appling 12V directly to the motor. Edited November 19, 2014 by Barney Eaton (see edit history) Link to comment Share on other sites More sharing options...
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