DanClarke said:
You have already proved the other side of the wiring is fine with your jumper because your pump fires and runs and then stops after a while (presumably until it reaches a required charge pressure for the system).
Click to expand...

Not the case all the prerequisite's are bypassed and the pump is just direct powered.
I "assumed" the bridge wire came out a bit and lost contact;).

Its the control side needs checking first. now if the pump was just running and not producing pressure it would just continue to run (may trip on high temp).

When my pump runs I can hear the change in noise as it gets up to pressure, so it could still be the pump as his brakes seem weak.

J
 
marjon said:
Ok

So as it too hot outside I went to the garage with me meter:).
Please not the relay sockets and the meter setting.

View attachment 269950

Pic 1 shows permanent live.

View attachment 269951
View attachment 269952

Pic 2 & 3 show the socket's of concern this is ignition on and brake pedal has been pushed many times. Checking voltage.

View attachment 269953

Pic 4 ignition off.

View attachment 269954

Pic 5
Ignition off (meter change) checking for ground, good enough;)

View attachment 269955

Pic 6
Put the relay back in and turned on the ignition, the pump ran for 20-30 seconds, turned off ignition and removed relay, No ground as pressure switch has switched.
View attachment 269956

Pic 7
Same situation as above but I put it on the same meter setting as you have been using.


Hope that helps:)

J
Click to expand...
Thank you for this I will try this and hope to find the issue,
 
Ok I have tested the voltage pin 30 has 12.4 v and pin 86 has voltage 12.4 v pin 87 and pin 85 have 0 volts with ignition on
 
Not sure if this is anything but I checked the abs sensors at the front and there is no voltage going to either side?
 
Faizey76 said:
Ok I have tested the voltage pin 30 has 12.4 v and pin 86 has voltage 12.4 v pin 87 and pin 85 have 0 volts with ignition on
Click to expand...

That all makes sense.
Pins 87 and 85 should go to earth. We already know your pump runs if you bridge across so that pin is fine.
Its the last 1 you need to concentrate on.
If you look at the attachments I posted earlier you will see it goes to the pressure switch then to earth. You will also see the pressure switch has 3 parts to it, but they all earth out to the same final point. If that point is bad then none of the other switch parts will work as well. As 1 of those also sends a signal to the ABS ECU and "presumable" tells the ECU the ABS is fit and working, if not it shuts down that part and will I guess show a light on the dash. if the system is shut down then it probably wont send any voltage to the ABS sensors so this could be your problem you noted so leave that for now.

You need to pull the plug on the pressure switch and check the line for continuity (not volts there will be none)

1. plug to fuse box relay slot, should read "0" on your meter.
2. Plug to earth, should read "0" on your meter.

I have added a couple attachments to aid identification of the pins you need to check

J
 

Attachments

  • C184 ABS pressure sensor connector.pdf
    37.4 KB · Views: 163
  • C184 location.pdf
    231.9 KB · Views: 137
marjon said:
That all makes sense.
Pins 87 and 85 should go to earth. We already know your pump runs if you bridge across so that pin is fine.
Its the last 1 you need to concentrate on.
If you look at the attachments I posted earlier you will see it goes to the pressure switch then to earth. You will also see the pressure switch has 3 parts to it, but they all earth out to the same final point. If that point is bad then none of the other switch parts will work as well. As 1 of those also sends a signal to the ABS ECU and "presumable" tells the ECU the ABS is fit and working, if not it shuts down that part and will I guess show a light on the dash. if the system is shut down then it probably wont send any voltage to the ABS sensors so this could be your problem you noted so leave that for now.

You need to pull the plug on the pressure switch and check the line for continuity (not volts there will be none)

1. plug to fuse box relay slot, should read "0" on your meter.
2. Plug to earth, should read "0" on your meter.

I have added a couple attachments to aid identification of the pins you need to check

J
Click to expand...
Thank you for this, I will do this today, and check for continuity, and report back I will check everything you have suggested,

Dean
 
Ok I got some help from a work colleague who is an electrician, he has just checked the continuity from the pressure switch plug to earth all pins record 0.00, all the earth points are good he took the 3 blots out of the fuse box and checked the connections underneath for damage nothing, we have checked all the fuses they are fine, the only suggestion was from my mate was could be ignition position if that triggers the pump?

I have bridged the pump it came on and switched off after 20 seconds brave pedal solid, so I’m thing the pump is fine could it be the pressure switch as suggested by Data?
 
Faizey76 said:
Ok I got some help from a work colleague who is an electrician, he has just checked the continuity from the pressure switch plug to earth all pins record 0.00, all the earth points are good he took the 3 blots out of the fuse box and checked the connections underneath for damage nothing, we have checked all the fuses they are fine, the only suggestion was from my mate was could be ignition position if that triggers the pump?
Click to expand...

Firstly great you have some help.
We have discussed this and yes the ignition "on" triggers the pump, If the pressure switch "asks" for it.
I take it you showed him the diagrams?

Faizey76 said:
I have bridged the pump it came on and switched off after 20 seconds brave pedal solid, so I’m thing the pump is fine could it be the pressure switch as suggested by Data?
Click to expand...

If you bridge the relay the control side has no control, So it would not EVER switch off unless there is a thermal switch (I suspect there would be)

If your brake pedal is good cos somehow the pump got up to pressure and magically switched off with a duff pressure switch with the relay bridged I will eat my hat;).

If it is up to pressure somehow then you need to ask your mate to check across the pins on the switch.

Because I am getting a little lost. All I will say is if all the wires are good to ground as they should be then yes pressure switch, But;) As your pump seems to pressure or not as it sees fit it could well be the pump as your brakes were not sounding the best in earlier posts:confused:.

You really are stressing my grey cells:).

Put the relay back in and see what happens on the drive, start the car does the pump run then stop. push the pedal a few times does the pump run a stop?

J
 
I posted a bid yesterday of me using the jump wire the pump come on and when it reached pressure it cut off,

after I jumped the pump my break pedal was perfect, relay back in ignition on but no pump, I pressed the brake pedal a few times I do have some better breaks but no abs pump working, I’m going to get a second hand abs unit that is tested and working and. Swap it over the pressure switch secondhand is about the same price. I need to fix this as it’s my everyday car,
 
Faizey76 said:
I posted a bid yesterday of me using the jump wire the pump come on and when it reached pressure it cut off,
Click to expand...

Is there any particular hat you would like me to eat:rolleyes:.

I can only work on what I see:).

Let us know how you get on:)
J
 
With the plug off, you need to check the pressure switch which is certainly the most likely problem, I haven't got RAVE on my tablet, but I will post the pins to test later when in the office.
 
Datatek said:
With the plug off, you need to check the pressure switch which is certainly the most likely problem, I haven't got RAVE on my tablet, but I will post the pins to test later when in the office.
Click to expand...
Thank you I really I really appreciate
 
Datatek said:
With the plug off, you need to check the pressure switch which is certainly the most likely problem, I haven't got RAVE on my tablet, but I will post the pins to test later when in the office.
Click to expand...

Sure I posted that? Or certainly enough to work it out;).

J
 
Faizey76 said:
Thank you I really I really appreciate
Click to expand...
With the ignition off, pump the brake pedal a few times to release any pressure.
Unplug the connector.
With your meter on 200 ohms
Put the probes between pin 5 and pin 2 the meter should read zero.
Put the probes between pin 5 and pin 4 the meter should read one.
Put the probes between pin 1 and pin 3 the meter should read one.
The first test is the important one ans that is the contact that operates the relay to run the pump, any reading other than zero is no good.
 
You must log in or register to reply here.

Similar threads

Faizey76
Range Rover p38
Replies
0
Views
329
Faizey76
Faizey76
A
Air suspension problems
2
Replies
30
Views
3K
Alec1943
A
C
Head lights
2
Replies
29
Views
2K
Mark Piercy
Mark Piercy
S
2001 range rover p38 auto gear dox issues
Replies
2
Views
1K
kermit_rr
kermit_rr
N
P38 abs / traction fault.
Replies
4
Views
1K
Neil.ms
N