PHC Failure warning on 03 Cayenne S

[Rising_Sun]

Hi All,

Ben a while since I was on here as I sold a Boxster S 3 years ago, but I'm back now as I just bought a Cayenne S, an 03 with 55,000miles. Very nice throughout, drives smoothly and just had a major service including a battery and coil packs (all 8). its got a warning light, its showing PHC failure. I've understood this to be Parking Hill Control? Does anyone know the resolution to this problem?

Any advice gratefully received!

[Loren]

PHC = Porsche Hill Control. The hill-holder function on Tiptronic S (or Porsche Drive-Off Assistant on vehicles with manual transmission) allows the driver to stop on a hill and drive off again without having to operate the brakes. It also enables a steady slow descent down steep slopes or icy mountain roads at speeds of up to 20 km/h (12.5 mph) using engine braking. This is provided by the engine drag-torque control (EDTC) system, which prevents wheel lock-up on overrun or following downshifts on low-grip surfaces. Selective braking is applied to individual wheels resulting in a considerable increase in steering precision.

I think you will need a Porsche PST2 or PIWIS tester to further diagnose.

It could be a reset is needed after the battery issue.

[Rising_Sun]

Hi, I really appreciate the reply, thanks very much Loren.

Only other thing I've had to do is change a headlamp bulb which turned out to be simple :thumbup: so I'm really pleased with it - great to be back with Porsche and renntech.org (the BMW Z4 was reliable but bland!).

Cheers

James

[Rising_Sun]

Ok I've had a recurrence, every now and again I get the PHC Failure warning. After some research I read the TSB and it suggested cleaning the connector on the pedal distance sensor, attached adjacent to the mast cylinder. Here is a photo of the sensor:

http://www.autopartsway.com/PartList.cfm?Porsche/allY/allMd/allSmd/allEn/allB/Electrical,_Lighting_and_Body/Sensors/Brake_Pedal_Position_Sensor/pagenum1/tabS

Fiddly to get to as it involves removal of a number of plastic panels, the wipers, and the most fun was the firewall panel section! Even more fun replacing all the above, particular cussing was heard when replacing the firewall and it's rubber seal :)

Anyway I cleaned the connector and replaced it so let's see how it goes.

Otherwise the cayenne is fantastic and runs really well.

Edited June 17, 2012 by Rising_Sun

[StevieG]

Would that sensor cause the psm to fault also?