Hi,

I have a 2010 Ford Focus 1.6 TDCI Zetec S 60,000 miles

Having an ongoing problem with error code p0299 'turbo underboost' where the car has lost power and will go into limp mode (very frustrating)

I have changed all the filters - oil,fuel,air, recently had the DPF filter carbon cleaned professionally. 

Found a split in the air intake hose which was replaced. 

The turbo is looking brand new, no cracks spinning freely.

 

Anyone out the have the same problem or have fixed this problem bit of help/advice would be great thank you.

 

 

have you checked your turbo vacuum lines? if they split you'll have issues.

thanks mate ill have a look at them when the weather drys up. I've give them a look but not very thorough.

soon as i seen the split in the hose i just assumed it was that but obviously theres something else

Just stripped it down. No splits anywhere

On 21/11/2016 at 11:45 AM, whitelock90 said:

Having an ongoing problem with error code p0299 'turbo underboost' where the car has lost power

It is usually a turbo actuator problem. As far as I can tell, the 1.6TDCI has a vacuum operated actuator, with no position feedback. (The 2.0TDCI & 1.8TDCI both have actuator position sensors). This means the ECU has no way to know what is wrong, and whether the actuator is moving or not, except by using the MAP sensor to measure the boost pressure.

So fist check the actuator rod moves freely. Then pull off the little hose to the vacuum port on the actuator, and apply vacuum to the actuator (suck hard!, or tap into the engine vacuum system somewhere.) See if it moves ok.

If ok here, locate the solenoid valve. It may be low down at the back of the engine, or perhaps the passenger side inner wing. Follow the hose from the turbo. Check the electrical connector, if that is ok, remove & test or just replace the valve. It can be tested by applying 12v to the valve terminals, but this needs a little care. It is just possible it has an inbuilt diode, and is hence polarity sensitive. Pin 1 (Gn-Bu wire on the wiring harness) should be +ve.

Another possible fault area is the MAP sensor, as this measures the boost. Its reading can be checked by a suitable diagnostic system. Also check its electrical connector & its fitting to the inlet manifold.

 

 

5 hours ago, Tdci-Peter said:

It is usually a turbo actuator problem. As far as I can tell, the 1.6TDCI has a vacuum operated actuator, with no position feedback. (The 2.0TDCI & 1.8TDCI both have actuator position sensors). This means the ECU has no way to know what is wrong, and whether the actuator is moving or not, except by using the MAP sensor to measure the boost pressure.

So fist check the actuator rod moves freely. Then pull off the little hose to the vacuum port on the actuator, and apply vacuum to the actuator (suck hard!, or tap into the engine vacuum system somewhere.) See if it moves ok.

If ok here, locate the solenoid valve. It may be low down at the back of the engine, or perhaps the passenger side inner wing. Follow the hose from the turbo. Check the electrical connector, if that is ok, remove & test or just replace the valve. It can be tested by applying 12v to the valve terminals, but this needs a little care. It is just possible it has an inbuilt diode, and is hence polarity sensitive. Pin 1 (Gn-Bu wire on the wiring harness) should be +ve.

Another possible fault area is the MAP sensor, as this measures the boost. Its reading can be checked by a suitable diagnostic system. Also check its electrical connector & its fitting to the inlet manifold.

 

 

Thanks for that mate sounds very thorough. I have checked the if the rod moves freely which it does but didn't look into the vacuum and others. I'll try that next thank you 

Car is fixed. It was the boost pressure soloniod bought off euro parts for £58 👍🏼

Hi Remi,

I have had similar problems. How did you determine that it was the boost pressure solenoid?

Summary of my issue is that the car suddenly lost boost one day and it won't go above 1.8bar at about 3000rpm. Engine has been terracleaned, fuel filter replaced, air filter replaced and no leaks in system.

Cheers

On ‎07‎/‎12‎/‎2016 at 4:33 PM, whitelock90 said:

Car is fixed. It was the boost pressure soloniod bought off euro parts for £58 👍🏼

Can you also tell me the part number you bought? :)

Back from Garage again.Turbo has excessive play and the oil seals have failed. Game over :(