ABS pump stays on
03-01-2007, 03:24 AM
#1
Racer
Thread Starter
ABS pump stays on
Only occassionally, maybe once every 3 months and usually after a long run, I pull up and shut down and lock up the ABS pump can be still heard running in the front.
Every time this has happened I have disconnected the battery and of course that stops it.
When I come back to the car maybe an hour later and hook up the battery all is well again with the pump cycling in and out and brakes working well.
Could this be a faulty relay?
Which relay is it?
As usual thanks for your help.
Regards,
Michael Gibney
Every time this has happened I have disconnected the battery and of course that stops it.
When I come back to the car maybe an hour later and hook up the battery all is well again with the pump cycling in and out and brakes working well.
Could this be a faulty relay?
Which relay is it?
As usual thanks for your help.
Regards,
Michael Gibney
03-01-2007, 08:54 PM
#4
If it's an early (pre 91) C4, the ABS relays should have been replaced. If they haven't and are dated with the car's age..the boost pump relay may be sticking. The end result is the pump will run, overheat and burn up the wire harness and plastic feed pipe. Replace both the relays anyway (and the fuel pump one too) they don't last for ever.
ABS relay 964 615 135 00
ABS relay 928 615 124 01
Fuel relay 993 615 227 00
Alternative is the pump pressure sensor is seeing too low a pressure and is trying to maintain it correctly. Get the pressure checked.
ABS relay 964 615 135 00
ABS relay 928 615 124 01
Fuel relay 993 615 227 00
Alternative is the pump pressure sensor is seeing too low a pressure and is trying to maintain it correctly. Get the pressure checked.
03-02-2007, 11:46 AM
#7
Nordschleife Master
When it runs on , try pull the wires from the green pressure switch and see if it goes off .
If it does go off , check the switch and see if its "closed" , when it should be open .
"The pump in front of the battery (up against the front bumper)"
Thats the hydraulic pump . The abs pump is on the floor near the gas tank .
The relays for the abs might not do anything for the hydraulic pump , but I don't know .
If it does go off , check the switch and see if its "closed" , when it should be open .
"The pump in front of the battery (up against the front bumper)"
Thats the hydraulic pump . The abs pump is on the floor near the gas tank .
The relays for the abs might not do anything for the hydraulic pump , but I don't know .
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03-02-2007, 11:57 AM
#8
The 964 615 135 00 the pump relay. Anything dated 1990 or earlier should have been changed. (this was the same time as fuel gauge problems). During the C4 early life, there was a service action to replace that relay due to a fault.
Nowadays, we change those relays (and the fuel pump relay) if more than 5 -7 years old.
There may still be a pressure sensor fault. Relay changing is a preventive maintenance issue.
Nowadays, we change those relays (and the fuel pump relay) if more than 5 -7 years old.
There may still be a pressure sensor fault. Relay changing is a preventive maintenance issue.
03-04-2007, 07:01 AM
#10
Racer
Thread Starter
Ordered relays from Porsche Centre Melbourne, about $300.00 for the 3 of them, will be about a week coming (one from Germany).
There seems to be some confusion, what happened to me is this....
1. About 2 years ago the brakes failed when the plastic fitting at the pressure pump inlet melted. Replaced the line and fitting - it is a one peice assembly. Brakes work fine.
2. Pump takes about 10 seconds to presurise when cars has been standing for 8 hours or more.
3. Occassionally, perhaps 4 times a year after a long run, the pump stays on even when the engine stopped and key out.
4. The pump that is running on is the one at the very front, the brake pressure pump, the one with the pressure switch on it.
5. Pulling the earth lead on the battery stops it (it would be a worry if it didn't!).
6. An hour later it is fine and cycles ok, all normal.
So the relay is a prime suspect, all three on order, I am sure to get the right one!
When the new relays are in I will pull the pressure pump relay apart and will look for the obvious burnt contacts, beyond that I would not know what to look for. I will report back when the repair and said inspection is done.
Regards all,
Michael Gibney
There seems to be some confusion, what happened to me is this....
1. About 2 years ago the brakes failed when the plastic fitting at the pressure pump inlet melted. Replaced the line and fitting - it is a one peice assembly. Brakes work fine.
2. Pump takes about 10 seconds to presurise when cars has been standing for 8 hours or more.
3. Occassionally, perhaps 4 times a year after a long run, the pump stays on even when the engine stopped and key out.
4. The pump that is running on is the one at the very front, the brake pressure pump, the one with the pressure switch on it.
5. Pulling the earth lead on the battery stops it (it would be a worry if it didn't!).
6. An hour later it is fine and cycles ok, all normal.
So the relay is a prime suspect, all three on order, I am sure to get the right one!
When the new relays are in I will pull the pressure pump relay apart and will look for the obvious burnt contacts, beyond that I would not know what to look for. I will report back when the repair and said inspection is done.
Regards all,
Michael Gibney
