Hi David,
I’ve been mulling over your observation that the problem appears to be time - and therefore oil temperature? - dependent, and I believe the error code you mentioned relates to a lack of clutch pressure. Unlike the clutch on a manual transmission which is normally closed, it seems that those on the PDK transmission are normally open and are engaged by hydraulic pressure.
As oil temperature rises its viscosity reduces and it becomes thinner. The transmission’s electro-hydraulic “command-block” contains multiple solenoid-operated valves and accompanying seals, and when the oil becomes thinner it’s more likely that any frailties in the seals due to high-mileage ageing will cause leakage, and therefore erratic clutch engagement. Auto transmissions have been around for a long time and I would imagine that solenoid valve technology is very robust, so probably it’s more likely that leaks will occur in the seals rather than be due to valve failure.
No doubt you’re seeing where we’re heading here: unless the diagnostics are pinpointing a specific valve [and seal?], your specialist is going to be in the dark when it comes to trying to locate a replacement, assuming that’s possible.
A note of caution. I came across this June ‘22 post on Rennlist from a Russian chap who managed to source various parts from ZF [solenoids, clutch-pack and pressure sensors]. Weren’t sanctions against Russia supposed to be in place by then, so I’m unsure how believable this is?
As far as I can make out, after fitting the replacement parts he was unable to reprogram the transmission and reverted to the original setup … which worked without encountering the previous problems!
All food for thought, although I’m not sure if it helps you to decide what to do next.
Jeff
Edit: Please can I add a further observation David. From what I’ve read on individual posts and on the sites of the few companies that have attempted to repair PDK transmissions it seems that one of the main pitfalls appears to be recalibrating the system post-repair, and I would say that it’s essential that your repairer has access to Porsche’s PIWIS diagnostics to perform the task. Apparently even then success isn’t guaranteed, and it’s been reported that sometimes several attempts have been required to achieve a fully-calibrated system.
I’ve been mulling over your observation that the problem appears to be time - and therefore oil temperature? - dependent, and I believe the error code you mentioned relates to a lack of clutch pressure. Unlike the clutch on a manual transmission which is normally closed, it seems that those on the PDK transmission are normally open and are engaged by hydraulic pressure.
As oil temperature rises its viscosity reduces and it becomes thinner. The transmission’s electro-hydraulic “command-block” contains multiple solenoid-operated valves and accompanying seals, and when the oil becomes thinner it’s more likely that any frailties in the seals due to high-mileage ageing will cause leakage, and therefore erratic clutch engagement. Auto transmissions have been around for a long time and I would imagine that solenoid valve technology is very robust, so probably it’s more likely that leaks will occur in the seals rather than be due to valve failure.
No doubt you’re seeing where we’re heading here: unless the diagnostics are pinpointing a specific valve [and seal?], your specialist is going to be in the dark when it comes to trying to locate a replacement, assuming that’s possible.
A note of caution. I came across this June ‘22 post on Rennlist from a Russian chap who managed to source various parts from ZF [solenoids, clutch-pack and pressure sensors]. Weren’t sanctions against Russia supposed to be in place by then, so I’m unsure how believable this is?
Panamera gts PDK error P17B1 / P17B2 - Rennlist - Porsche Discussion Forums
Panamera - Panamera gts PDK error P17B1 / P17B2 - Hello club, i have panamera gts 2015, 112k km, sometimes after hard driving in sport+ mode, and shifting gears every 3 seconds, i getting gearbox errors P17B1 and P17B2, its mean clutch pressure, after restart engine - its just empty it and...
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As far as I can make out, after fitting the replacement parts he was unable to reprogram the transmission and reverted to the original setup … which worked without encountering the previous problems!
All food for thought, although I’m not sure if it helps you to decide what to do next.
Jeff
Edit: Please can I add a further observation David. From what I’ve read on individual posts and on the sites of the few companies that have attempted to repair PDK transmissions it seems that one of the main pitfalls appears to be recalibrating the system post-repair, and I would say that it’s essential that your repairer has access to Porsche’s PIWIS diagnostics to perform the task. Apparently even then success isn’t guaranteed, and it’s been reported that sometimes several attempts have been required to achieve a fully-calibrated system.
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