Dreaded Reduced Engine Performance

Had the dreaded reduced engine performance on my 2009 FL.
Scan throws up only the P0299 DTC turbo underboost - with no other related codes (also had a B1D13(14) which I think is related to the boot light that has loose wiring.

This happened after a cold snap -12 degrees with cold starts that would take a 3/4 cranks to get started.
Clearing the codes would set everything back hunky-dory for 15-20 mins.

Things done so far.

• Checked the intercooler hose which is in perfect condition.
• Cleaned the MAP and MAF and reset the codes

Was going to check the turbo actuator but haven't got around to it just yet
Nearly replaced the fuel filter as I thought the diesel could have gelled and clogged up the filter but seems to be okay.

After cleaning the sensors, and clearing the codes, so far, so good. Haven't seen anything come back but I've only driven it 30-40 mins or so after clearing the codes.

Is the P0299 code linked to MAP/MAF sensors?
I'm fingers crossed that it was a simple, cheap fix.

Car had to go in for a steering fluid leak so I really hope I don't have to throw more money into fixing these faults.

HaggisMuncher said:

Is the P0299 code linked to MAP/MAF sensors?
I'm fingers crossed that it was a simple, cheap fix.

Click to expand...

P0299 is an under boost code.
It can be several things, but start with the boost hoses, particularly those from the intercooler to the throttle body, as they have a habit of splitting.

Sluggish starting when below freezing is probably the glow plugs. They fail quite often, as they are used for emission reduction after starting, even if they're not needed for actual starting.
Glow plugs are used for starting when the coolant is under 5°C.

Fitting new plugs should solve the cold starting issue.

Nodge68 said:

P0299 is an under boost code.
It can be several things, but start with the boost hoses, particularly those from the intercooler to the throttle body, as they have a habit of splitting.

Sluggish starting when below freezing is probably the glow plugs. They fail quite often, as they are used for emission reduction after starting, even if they're not needed for actual starting.
Glow plugs are used for starting when the coolant is under 5°C.

Fitting new plugs should solve the cold starting issue.

Click to expand...

Just got the car back from the power steering issue. Needed a new high pressure hose as I suspected.

I thought the reduced engine performance was a thing of the past since I cleaned the MAP and MAF sensors but unfortunately it came back.
Still the only code the scanner has picked up is the PO2099.
The scanner is one of those cheap wifi ones you pair with your phone though.

I have to drive 130 miles tonight and I hope it'll last on the motorway. I can clear the codes and the fault goes away temporarily.

I'm convinced that, due to the fact that the car will behave as expected with the faults clear that it must be some kind of sensor fault.
Losing my mind at this problem and I'm close to just shelling out for a new turbo in hopes that fixes it

HaggisMuncher said:

Losing my mind at this problem and I'm close to just shelling out for a new turbo in hopes that fixes it

Click to expand...

Have you checked the hoses?
It's a good plan to check the turbo vane lever moves freely through its whole range of movement, but make sure you remove the tiny C clip from the actuator first, as moving the actuator by hand will damage it.
It's also possible the actuator has a fault.

Nodge68 said:

Have you checked the hoses?
It's a good plan to check the turbo vane lever moves freely through its whole range of movement, but make sure you remove the tiny C clip from the actuator first, as moving the actuator by hand will damage it.
It's also possible the actuator has a fault.

Click to expand...

Had another look and while driving over the last couple of days I've been hearing what sounds to be leaking air when the turbo spools up.
It's definitely not the little 45 degree hose that connects directly to the throttle body.

It sounds like it's coming from the hose that small section connects to - from the intercooler to throttle body although could be the hose from the turbo to the intercooler closer to the turbo.

That's stopped my in my tracks with looking into the actuator - struggling to get the bloody wheel arch out though as the bolts just keep spinning

The arch liner you mean?
It doesn't cover much, but a trim removal tool used as a lever will get them off, they're only plastic nuts.

It's easy to get at the actuator from below, rather than through the side.

I've had my actuator oft recently. Got to it from below and behind the big metal bar. Also through where the drive shaft goes. Lay underneath with it on HippoRamps (TM). Sent mine to www.ecutesting.co uk for test and repair. That way you get the same actuator back, which was matched to yer turbo in production. Will have been calibrated together. Worth a go at a repair than replacing the whole turbo, if the turbo ain't working as it should