change master brake cylinder cause psm faulty light?
#1
12-26-2014, 02:41 AM
change master brake cylinder cause psm faulty light?
i changed my master brake cylinder to a cylinder from a car without psm (have two 12mm sockets, the 996 psm has one 10mm front and 12mm rear) - i used a 10mm adaptor.
the brakes works fine - no comparsion like befor - but after the first start of the engine the abs/psm light appears in the dashboard.
i read in the forums that the secondary brake circuit has to be bleedet - i let this do the porsche dealer because my durametric cannot start the booster pump.
no result - after driving 1/2 day or sometimes only after 5min the psm/abs light appears.
now i have changed the maf sensor to an aftermarket product - the psm/abs light appears after one day!
in the workshop manuel there is an instruction to test the psm - i had an failure on pin 2 where is a voltage from about 5V instead of 0,3V - i can find no problem in the harness nor know where the cable connects in the main harness?
if the lights are off the abs/psm works fine - but if they on - the abs/psm is not working.
in durametric i have the fault pressure sensor 4460 - but this sould come often.
do you think psm recognices the other master brake cylinder? sometimes the light apears also if i dont have braked!
bye
wolfgang
the brakes works fine - no comparsion like befor - but after the first start of the engine the abs/psm light appears in the dashboard.
i read in the forums that the secondary brake circuit has to be bleedet - i let this do the porsche dealer because my durametric cannot start the booster pump.
no result - after driving 1/2 day or sometimes only after 5min the psm/abs light appears.
now i have changed the maf sensor to an aftermarket product - the psm/abs light appears after one day!
in the workshop manuel there is an instruction to test the psm - i had an failure on pin 2 where is a voltage from about 5V instead of 0,3V - i can find no problem in the harness nor know where the cable connects in the main harness?
if the lights are off the abs/psm works fine - but if they on - the abs/psm is not working.
in durametric i have the fault pressure sensor 4460 - but this sould come often.
do you think psm recognices the other master brake cylinder? sometimes the light apears also if i dont have braked!
bye
wolfgang
Last edited by pold9000; 12-26-2014 at 03:24 AM. Reason: changed pin 3 to 2
#2
12-28-2014, 03:14 AM
Wolfgang, at this moment I'd change the brake light switch located at brake pedal. If your new MC produces brake pressure (above some preset limit) before the switch makes contact, then the Pressure Sensor Fault (P4460) activates.
Another thing is that aftermarket MAF you're using. If it's a genuine Bosch there should be no problem. But if it is a chinese copy from evilbuy, the reason is there...also if you're using a KN (or similar) oiled aircleaner you're heading to trouble.
MfG,
Another thing is that aftermarket MAF you're using. If it's a genuine Bosch there should be no problem. But if it is a chinese copy from evilbuy, the reason is there...also if you're using a KN (or similar) oiled aircleaner you're heading to trouble.
MfG,
#3
12-28-2014, 05:45 AM
[QUOTE=pete95zhn;4262470]Wolfgang, at this moment I'd change the brake light switch located at brake pedal. If your new MC produces brake pressure (above some preset limit) before the switch makes contact, then the Pressure Sensor Fault (P4460) activates.
i will change it but i drove now 2 days without psm light in snow with many abs/psm working, perhaps there was some rest air in the secondary circuit.
Another thing is that aftermarket MAF you're using. If it's a genuine Bosch there should be no problem. But if it is a chinese copy from evilbuy, the reason is there...also if you're using a KN (or similar) oiled aircleaner you're heading to trouble.
the MAF dont worked fine i had some failer items in the dme, the original bosch works good - actual values tested with durametric
thank you
wolfgang
i will change it but i drove now 2 days without psm light in snow with many abs/psm working, perhaps there was some rest air in the secondary circuit.
Another thing is that aftermarket MAF you're using. If it's a genuine Bosch there should be no problem. But if it is a chinese copy from evilbuy, the reason is there...also if you're using a KN (or similar) oiled aircleaner you're heading to trouble.
the MAF dont worked fine i had some failer items in the dme, the original bosch works good - actual values tested with durametric
thank you
wolfgang
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