DerekS

I'm having a bad time.

I have taken the car in twice now for this issue. Apparently it's a bad changeover valve...but there are many in the car, so it's hard to nail down.

Can anyone offer troubleshooting anecdotes for this fault I can pass on to service?

spiderv6

Presumably they are following the TSB?

DerekS

Not so far, if there's a specific number I can give them that would help.

My car is a 2014. The campaign was for 2012 wasn't it?

CSK 911 C4S

There's only 8 in the car I do believe. (corrected)

I know when mine faulted I did not have any heat inside the car.

Another popular valve to fail is the one that works the PSE.

991carreradriver

I don't understand, there is only one COV that effects the cooling system.

plenum

There is no TSB for the COV failures on cars beyond 2012.5.

For a comprehensive "overview" of COVs check out my blog post on this subject. Porsche 991 COV & Vacuum Lines Overview

For more reading enjoyment, you can also check-out WM 2400IN which is the official Porsche document on the COV and Vacuum Lines in the 991.1 cars.

DM me if you need more....

plenum

You only see one COV assigned to engine coolant, but note that there are multiple COVs tied to the same mechanical vacuum pump and vacuum lines. For that reason when you lose a COV to the exhaust flaps for example, you will receive an "Engine Coolant" system failure warning when it really doesn't have anything to do with your coolant system....

plenum

As for how many COVs are on a 991 (MY2012.5 through MY 2016), # ranges from 7 to 10 per below based on how your car is configured:

1. Air Cleaner Flap
2. Acoustic Simulator
3. Heater Shut-Off Valve
4. Exhaust Flaps
5. Coolant Shut-Off Valve on Engine Bypass Circuit
6. Tuning Flap
7. Shut-Off Valve on Heat Exchanger for Gear Wheel Set Oil
8. Shut-Off Valve for Clutch Fluid Heat Exchanger (PDK ONLY)
9. Tuning Flap (cars with full X-51 Power Kit ONLY)
10. Tuning Flap (cars with full X-51 Power Kit ONLY)

#9 and 10 are not a mistake on my part.... cars with X-51 option have multiple tuning flaps.

spiderv6

But there is for cooling system faults, all the way up to 2016.

991carreradriver

Good to know, I didn't really think through the connecting lines when I responded to the OP. So it appears that all interconnecting COV's have to be replaced one at a time to find the culprit.

plenum

Yeah, I don't know if there would be a corresponding code logged that would point to any one individual COV failure, or even a fault in the vacuum line. THe troubleshooting is likely partly based on what the issue is reported-as. Such as car sounding different, no heat when heat on, and so on. I have to think the mechanical vacuum pump would throw a code if that were the culprit, but not sure to be honest. You can actually get the coolant system fault message simply by pulling the vacuum line off at one point, so it is based more on loss of vacuum I guess....

Each time I've had a coolant fault appear on the '14 C4S it was a COV - exhaust flaps or heat exchanger.

TCallas

LexVan

Wow, I need a COV warranty. 10? Crazy. I see some out of warranty COV repairs in my future.

DerekS

As it turns out I lost two of them back to back.

Six more to go?

Jabs1542

i had a Coolant Failure fault due to COV, the repair ticket said they replaced 3 COVs. I thought they had a way to check them and found 3 out of spec. Now I'm wondering if they weren't just replacing COVs until the fault went away and they got it right on their third try.

I hope that's not the case because it could get expensive trouble shooting this on your own after warrantee.