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Low Revs, PSM loss, Cuts Out

911_AS

Well-known member
Joined
22 Apr 2013
Messages
915
I had a strange issue on my 991 this morning.

I was on my way to an OPC, and noticed the revs were a little low on idle. Even when warmed up, the car didn't maintain high revs, I had to switch over to manual to stop the PDK from changing up so I could keep the gear low.

Randomly, I then get an error message on the dash:

"PSM loss - possible to drive on carefully"
and then "Start/Stop operation Deactivated".

The car then splutters and cuts out completely, whilst I was sat at a set of red lights! Thankfully, I was right outside the OPC and managed to get it going enough to reach the car park.

Not sure if it was luck that this error occurred today of all days as I was going to OPC. My suspicion is it's battery related, but I can't be sure until OPC run their diags.
 

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This is one of those .. " how long is a piece of string answers " .

There are many things i can think of from high pressure fuel pump to throttle body potentiometer failure , let alone all the possible electrical faults .

Dam good luck to happen on the way to the OPC though .

Fault codes are pretty good on 991 so they will have a good idea after a code read out .
 
Started my 997.1 up last month after 3 months or.

The engineer was not firing on all cylinders and the car was shaking like mad, the warning light came on and said something like 'goto your nearest dealer'

Turned the ignition off then started it up again and was fine.

No idea what was going on but worried the hell out of me. :?
 
Best guess there is the fuel pressure took a while to build up ..

Again a fault code check would say if theres any under lying problems that have only shown them selves by the long layover .

Drive it and see how it goes .. i expect it will be fine .
 
Demort said:
Best guess there is the fuel pressure took a while to build up ..

Again a fault code check would say if theres any under lying problems that have only shown them selves by the long layover .

Drive it and see how it goes .. i expect it will be fine .

Thanks, something I would never of thought of.

Driven not twice since and it has been totally fine.

Thanks fella
 
Demort said:
This is one of those .. " how long is a piece of string answers " .

There are many things i can think of from high pressure fuel pump to throttle body potentiometer failure , let alone all the possible electrical faults .

Dam good luck to happen on the way to the OPC though .

Fault codes are pretty good on 991 so they will have a good idea after a code read out .

Thanks Demort. Awaiting a call from OPC today to find out the root cause and fix. Watch this space.
 
This is now resolved.

Issue was misfiring cylinders - Vavle lift control. A new Valve Lift solenoid in bank one was needed (the one that sits between the ignition soils).

All work was done under warranty and the car now drives as expected.
 
Thats interesting .. well more so for me !

Ive done a couple of these solinoids so far and no customer has complained of a PSM fault before ..

One for me to add to my list of customer descriptions and possible faults :thumb:


Oh and glad its fixed young man :D
 
deMort said:
Thats interesting .. well more so for me !

Ive done a couple of these solinoids so far and no customer has complained of a PSM fault before ..

One for me to add to my list of customer descriptions and possible faults :thumb:


Oh and glad its fixed young man :D

Thanks DeMort! And apologies for the appallingly delayed reply, sir.

:thumb:
 
No reply needed young man :D

I found it an interesting fault and not one i would have thought of from the symptoms , all good info for me so thanks for posting the final fault :thumb:


If theres any mechanics reading this then an interesting point ive found out about this fault ..

If the solinoid is faulty then when you remove it oil will run out of the hole it was in where as a non faulty solinoid when removed wont .. a boreing fact but true none the less :D
 
I'm no technician, unless a computer keyboard is close by. But I always enjoy reading your mechanical-minded posts. Keep 'em coming, deMort.



:thumb:
 

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