Fault Codes P 2181 & P 3081

I am struggling with fault codes above on my 2005 997.1 3.6L Tiptronic. If anyone can help me I would be so grateful. I know DeMort has dealt with these issues. P 2181 Cooling Performance P3081 Coolant Temperature Implausible After about 15 minutes running the red ! comes on dash with a "Failure Indicator" and the coolant sign and the red warning flashing once per second in the coolant gauge. The first time this happened a week ago I cleared the codes and it drove fine and all back to normal. Drove it today and up come the same faults. The water temperature is very slow to rise and gets to 50C and drops back to the starting position (40C). The oil temperature does not rise at all. The instant the codes are cleared the water temperature gauge flicks to 80C and the oil temp gauge becomes normal. My research leads me suspect a faulty valve on the tiptronic gearbox that controls the engine coolant entering the gearbox heat exchanger. My problem is that it could also possibly be temp sensors/thermostat or other problems. I can't see any coolant leaks and the coolant level is spot on. I also can't understand why the instant I clear the codes the gauges return to normal. Any help will be gratefully received. Thanks

I hope this helps, from PIWIS P2181 P3081 A couple of common possibles there..

Thank you. Very useful info for me to start with.

Hi Ralphmusic Ive just done a full heat cycle without fault codes and car is running normally. When I connected my car soft Porsche scanner I checked the battery voltage before starting the engine and it showed 11.4 volts despite the battery being on a charger a few days ago. This seems too low and once engine running showed 13.5 volts. I know these cars are vulnerable to fault codes and dash warnings when volts get low although I put it on a charger regularily. Could this possibly be causing the problem. I think I will replace the battery anyway as I have had the car 4 years . What do you think ?? Thanks for your help.

John, Anecdotally the more modern water-cooled cars seem to very susceptible to poor battery condition, so from your comments it’s possible that this could be the source of your problem. I think a battery replacement would be an advisable first step to see if this clears your issue. Jeff

I bow to Jeff's greater knowledge, I just can access the diagnostic to-do list.

Many thanks both of you. I will replace the battery first as I think I should anyway and if the problem persists then I will work through the diagnostics list.

Right I replaced the battery without problems apart from the expected PSM fault which cleared after a few miles driving. I just scanned for codes which were clear but noticed the scanner reported the coolant temp to be -50C despite a fully up to temp engine. Could this be connected with my original cooling fault codes ? and indicate a definate failure of the engine coolant sensor ?? Thanks

It does sound as though replacing the coolant sensor would be worth a punt John because clearly something’s not right there. Hopefully not a huge expense, although we’re talking Porsche parts prices unless you can find an aftermarket equivalent. Hope you get a satisfactory solution. Jeff

Thanks Jeff I'll get one ordered.

I know I posted this problem some time ago but Ive only just got my 997 out from its winter slumbers !! It was the coolant valve on the Tiptronic heat exchanger . This has been replaced at modest cost and the car is fixed ready for the Summer.

Thanks for getting back on this John and pleased to hear that the problem has been resolved at reasonable cost. Time to get out and enjoy the car! Jeff