flashing 4th and D Tiptronic - 986 Forum - The Community for Porsche Boxster & Cayman Owners

2002 tip, 986 S with 80K Flashing 4th and D after warm up, however transmission works fine and the normal lights come back in a minute or so, go to 4th and D again, etc as I drive. Automatic and manual function fine, just dont get the feedback in the dash lights when its out. I have heard this could be the transmission’s coolant vacuum valve. Does this circulate coolant through the transmission? That seems to be the simple fix and makes sense. I had the transmission serviced, new fluid, filter etc about 6 months ago, but the problem didn't completely resolve. Now with the warmer weather, I'm thinking I should iron out this issue. I have a durametric scanner, but it only shows alarm fault codes (historic, none present now) to be honest, I am not sure I'm using the durametric to its potential, it seems pretty lame when I do the short test on all modules, so I would welcome advice on this as well. would a faulty coolant vacuum valve potentially lead to heat issues with the tiptronic, manifesting in the 4th and D flashing?

Curious, have you changed the exhaust system on the car? Especially putting in secondary cat delete pipes?

Quotes source post: 593215

nope, stock exhaust and wondering if the cooling system is integrated with the tranny for cooling and replacing the coolant vacuum valve would assist in cooling transmission.

Quotes source post: 593213

That controls the coolant that goes to the trans cooler mounted on the transmission. Mine broke in half and car had to be towed it's only time. It's also a lot of fun to replace, it's the same type of valve that controls coolant to the heater. Valve is not very expensive.

P0710 Transmission temperature sensor P1823 Pressure Regulator3 P1818 Pressure Regulator2 transmission works normal, recent transmission service (tranny was already exhibiting the flashing lights) and fluid didnt look burnt or anything. I heard from the previous owner that when he got the car, the tranny was very low on ATF and he had it topped off. (it was not flashing the error lights) Again, I serviced the tranny after a couple of months and noticed the lights, this didnt stop the flashing. I am considering running a cleaner/flush in the tranny before doing a series of drain/fill operations with the hope that I can clean up the regulators of varnish before I give up and swap this out with an extra tranny I have. Anybody have a product in mind for this?

From a user on another forum, good information in here that I have validated as accurate. Sharing for the greater good... Our gearbox, a ZF type 5HP19FL, is nothing special; it's in oodles of Audis, BMWs and VWs through the same years as the 986 Boxster. Submerged in the fluid inside is a wiring harness that connects to various bits. There is a 2-wire thermistor that pokes its head out of this wiring harness; this is the ATF temperature sensor. It would appear that its plastic shrouding breaks down with heat and age, causing the device to malfunction and transmit spurious and/or no signals to the transmission control module. In my case the removed harness also displayed evidence of similar brittleness with the plastic electrical connectors that connect to the various solenoid valves. To sum up, if you have the D-4 flashing thingo happening on your dash AND the transmission does not go into 'limp' mode during those occurrences then the ATF temperature sensor in your Tiptronic is playing up. Replace the gearbox internal wiring harness and your problem will be solved. (You have to buy the whole thing as the thermistor is intergral and cannot be purchased separately) Don't take notice of comments about the transmission fluid level or purity, it's a furphy - in any case you'll have to drop the bottom to access the harness, so you will need to replenish with new fluid. Happy motoring! Wiring Harness Part Nos Porsche 986 325 611 00 ZF 1056 227 046 01

So, this issue isn't over...I am thinking that I have an overheating transmission, the cooling fans run and they cycle for sometime after i park it. Is there a transmission cooler I should look at? I have noticed that the 2 rubber flaps that my 2000 and 2001 have for trans-axle airflow are missing on this car, for what its worth. what should I check if I think my transmission is overheating?