olwe

Gentlemen,

I had code 4460 come up repeatedly, and then permanently. We have been through the entire fault check thread for 4460, including replacing the pressure switch. No luck. We now plan to either repair or replace the complete pump assembly. The car is a 2001 996 Turbo Tiptronic. The Durametric lists the unit as a Bosch 5.7 part number 996.355.755.50 and Supplier Part number 004156016610, but this is not the entire assembly. The complete unit is 996-355-955-CX and costs $4,900 from Sunset Porsche plus core charge.

According to Sunset Porsche the part numbers that fit are 996-355-955-57, 996-355-955-58, 996-355-955-59, 996-355-955-63, and 996-355-955-CX. There may also be a corresponding Bosch part number 0 265 225 101 but we have not removed the pump to read the part number on the unit. as the car is driveable.

I would appreciate a lead to a used pump or a recommended repair place, or further ideas on how to fix the problem.

mffarrell

Have you tried BBA Remanufacturing?

They rebuilt my ABS pump and control unit on my BMW E39. I think I paid $200 shipped, and got it back within 72 hours including a lifetime warranty.

theprf

You really need the Bosch part# off the bottom. You can read it with a mirror. Once you find that you can see what ones you can find. You need to match the Bosch number.

Is 4460 the return pump fault code? There's a couple MOSFET's on the PCB that seem to go bad, so it might be those need replacing.
Also, the return pump fault code seems to be related to overactive PSM intervention. To keep from blowing my ABS unit up I'm going to be using the dash switch to get rid of PSM for my future track days, until I am comfortable enough to unplug it altogether.

olwe

In response to mffarrell: Thaks for the advise on BBM. I have reached out to them asking if they can assist.

In response to theprf. Thank you for the advise on the mirror. We will check that out.
For track days I have used a switch under the front lid turning off the power to the ABS pump for years. Else my rear brakes would overheat in a very short time. Simple mod without a problem.

mcbit!

The return pump fault code is:
Fault Code 4266 -- Return Pump Fault
Diagnostic Conditions
- Return pump voltage and motor relay voltage actual values are evaluated and display implausible values.
- Open circuit in circuit to control module terminal 1.

Possible causes of fault
- return pump motor locked up/runs too easily
- Wire/plug connection faulty
- PSM hydraulic unit faulty


[​​Fault code 4460 -- Pressure sensor

Possible cause of fault
- Short circuit to ground/voltage or open circuit in circuit to control module terminals 25, 26 and 42
- Plug connection on stop light switch faulty
- Adjustment of the stop light switch not OK
- Wiring/ plug connection faulty
- Pressure sensor faulty (replace hydraulic unit)

I recently had a 4266 fault which was persistent but has now disappeared for the moment. in researching the PSM pumps I found the following:
The hydraulic side of the PSM Unit rarely fails, the vast majority are electronic failures or the fault is not directly related to the PSM unit itself. I believe this may also be true of the 4460 fault.
Although I cannot find any documented Porsche confirmation Porsche quotes only 955 numbers for the PSM unit however a number of people have quoted 755 on the units actually removed from their cars. This seems to back up the 755 designation retrieved from your car by Durametric.

Good luck in solving your problem.

​​​​​​​

olwe

Thank you for the advise.

We have resorted to having to replace or repair the complete ...955.. assembly.

wross996tt

As I indicated on 6speed, I have been fighting the same code for over a year now (replaced 3 switches). No track days. Closely watching for remedies.

theprf

I'd change the brake light switch first.
Also, do you have the 997GT3 master cylinder upgrade? That seems to cause this fault code. There are solutions using a brake proportioning valve to clear it up.

LordVicious

Module masters has some ability to rebuild the abs unit … https://modulemaster.com/products/bosch-5-7-abs-rebuild … good luck

wross996tt

I've got a couple of P-car mechanics contemplating the issue and one suggestion is to replace the "pressure switch" on the ABS unit. Don't know what that is? We've already tried to sensor associated with the brake pedal (3 times)

theprf

The pressure sensor is the small 3-pin device screwed into the ABS valve block. I have not been able to find it as a separate part. The Bosch part# for the sensor is 0 265 005 303. I believe the pressure sensor is used on all PSM equipped 996 - Turbo and normally aspirated, and probably 986 Boxsters too. You may be able to buy a cheap ABS unit for one of these cars and salvage the sensor.
I had this same code (4460) and I cleared it unplugging and replugging the main ABS unit plug and the sensor plug a few times, probably breaking up a bit of corrosion on one of the pins.

Carlo_Carrera

Sounds right.

wross996tt

That's a great idea...perhaps just some loose electrical connections. worth a try. Thanks much!

mcbit!

That may be what cured mine.

wross996tt

We did find the switch that attaches to the ABS unit available as a stand alone part. I believe the quoted price is about $400 and they are available. I think we're going to try the plug/unplug idea first and if that fails to cure the code, try the switch.