Slow down a bit, yes your pump maybe weak but still builds pressure and shuts down does it not? Your level sensor shows issues, ok with engine off so why not with engine running?
You say "new" pressure switch? your diagnostics shows that 1 side of the switch is bad, that would be where I would be looking not the pump (yet
)
Have you actually tested the switch at the switch? The posts from
@pwood999 give enough for you to do this.
I would still need to have a good look to understand the (6) in the pressure switch which may indicate the pump is weak?
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Sit down with a cuppa
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J
Thanks gents - appreciate the involvement and testing of your own equipment. Yes, you're correct - it does build pressure then shuts off, restarting every 3rd or so press of the peddle so I guess it behaves as if it's reaching the desired pressure.
So following your advice, I've studied the diagram
@pwood999 posted. Bear in mind I am not very practiced with electrical diagrams, can I just think out loud here?
Assuming the switch is working correctly:
Contact [4] is normally open/off. The Black/Purple (BP) wire should have 12v which, with a correctly operating brake fluid level sensor, would supply 12v to the BG wire that goes to both the ABS ECU and via Pin 3 into contact [4] of the ABS switch.
Contact [5] gets 12v supply from BW wire via Pin 4 and is mechanically connected to contact [4]. When the system is <110 bar, contact [4] won’t close and therefore BG won’t earth and will register 0 volts. If it is > 110 bar, [4] will close and BG will earth and [5] would open causing BW to be 0 volts.
I’m not sure I completely understand contact [6] but the BY wire feeding it at Pin 2 will close and earth at 180 bar and open below 140 bar causing BY to be 0volts
Therefore a correctly operating switch should behave something like this:
Below 110 bar – BG won’t earth (0v), BW will earth (12v), BY won’t earth (0v)
Over 110 bar – BG will earth, BW won’t earth, BY won’t earth until 180 bar then it should.
So all of this is to say, in order for the ABS ECU (or whatever causes the low pressure warning) to believe the system does not have a low pressure, BG should be 12v, BW would be 0v, BY hopefully 12v if its gets up to 180 bar.
Have I deduced correctly?
