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997.1 Turbo - Loss of boost / Boost Actuator Q

alastairb

New member
Joined
3 Feb 2016
Messages
48
first things first , my phone broke so I've lost the P codes I picked up scanning the OBD :wall:

I can recall though :

Boost Actuator Sluggish (both banks)
Boost Actuator Failure (Might have said "electrical fault" or similar)

I've got the (common) symptom of :
Boost not rising past 0.3 - 0.5 bar.
No Chrono Arrow in sports mode.


I've been under the car and noticed :
Both actuator arms move fine and return to position. There was a little corrosion on the passenger side so I popped it off and lubed it (I'll ask Specialist to use the proper lube next week).

To be honest the VVT end feels quite easy to move when the arm is popped off - not sure if this is normal?

Questions (sorry if a few).
Before car goes into to specialist next week....(for service anyways).
Under what scenario can I observe the actuator test , on Ignition on is the car supposed to do a sweep of the actuator movement ?

What vacuum hoses should I be checking, I've read a few posts of hoses popping off in places - Can someone point me into where I should be looking?

Before the issues, I had wife telling me it was intermittent on-off sluggish on her daily commute. Now its fully off boost so i think its slowly gone kaput rather than something failing suddenly - suggests to me a popped off hose might not be the problem but maybe a split pipe instead?

Also - Does the ECU need re-calibrating for the actuator movement ? I left the battery unplugged overnight but still no boost.

The fact the Sports / Chrono arrow is not showing , i've read the ECU is lowering boost expectations due to the Actuator not responding quickly enough , along with the Pcodes I've observed.
is 0.3->0.5 bar the base boost with no electronic control or just a measure of the current VVT position?

What's the procedure to reset the ECU if I've got both arms off and cleaned them up / re-lubed them?

Thanks and sorry for the waffle !
 
Ive seen actuators fail on 991 so they do seem to be getting common.

Lay underneath so you can see the rod then have someone turn on the ignition ( Dont start it ) you should see the rod move fully one way then the other .

Do the same for the other side.

My guess is one has failed .

Not aware of a dme calibration for these .. the sweep with ignition on does that .

Pipes as per graemeho thread , you could have a look in the boot at the engine just to make sure the pipes from the inter cooler havent come off or anything not connected to the airbox but it would unusual to have a fault there .... unless its just been serviced !
 
Hi, had exactly the same symptoms, I took the bumper off and checked the hoses, but couldn't find anything.

The actuators moved OK by hand and I thought were OK.

In the end it was nothing obvious to me and I passed it on to the specialists (9e in my case), where it turned out to be the driver side actuator was kaput.

I also one of the hoses at the back of the plenum had popped off, but in my case that was down to a poor install when I had some performance upgrades installed (which in your case its probablly unlikely unless you have had anyone fiddling with your plenum).

I think an actuator test via the PIWIS will answer whether its them or not.
 

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