P0299 Fault code finally cured

[Ecomatt]

I kept having this fault code rear its ugly head on me for a while now. The engine would sometimes be okay and then other days it would be underpowered. I checked the MAF sensor and that was working all in order. I checked all the boost hoses and vac hoses. They appeared all in order and I couldn’t see any obvious signs of damage or leaky joints. So I initially changed to the new revision diverter valve and took the car for a drive and the fault code came back. So I then changed to the new revision PCV valve and fitted it along with a new gasket. I could see that the valve was leaking and thought that was it. Or so I thought. I went out in the car for a drive and the fault code came back. I began thinking it might be the wastegate or something to do with the turbo. But then I had a moment of inspiration! I thought that it must be a sensor of some form that was giving incorrect readings. But I have no working knowledge of this engine, but thought they must all work pretty similar in design. Comparing it to my RS Focus and how that operated. I know the MAF sensor is fitted before the turbo. I thought there must be a sensor fitted after the intercooler to monitor boost pressure. I looked and saw a small sensor fitted above the throttle body and I proceeded to remove it. It was just held in by a torx screw. The sensor itself consisted of a metal wire hoop. Very similar to that of the MAF sensor. However it was covered in oil. The sensor is located near to where the PCV valve re-circulates into the inlet manifold. I got out my DX works brake part cleaner (also good for cleaning MAFs) Dowsed it heavily till all the oil film was dissolved and refitted. I took the car for a drive again and the engine instantly felt different. The was a lot more power and after a good drive of slow and fast driving. The fault code did not return. Happy Days!

I thought I would post my findings to help anyone else out there who is having the same problem as me.

[mtierney5]

Im having this code too!!! Im ignorant enough when it comes to car's so any chance of a few pics of where the sensor is and what it looks like????

Thanks guys,

martin.

[Ecomatt]

The sensor in question I cleaned is located just to the right of the dip stick, poking out from under the Grey part of the engine cover at the front. You can see a black lead coming out from the harness that clips on the sensor just above the throttle body.

I also had a slightly sticking N75 valve but that was a pain to get too! That is located in the most awkward place on the rear side of the engine near to the turbo. Plenty of cuts and scratches when I did that!

Have you got the newest revision PCV valve and Diverter valve. I would check those too, as it could be an easy fix for you? Is your car standard or remapped? Plus is it under warranty? If it is under warranty I'd take it in to get fixed. You could also consider a pressure test to see if there are any leaks anywhere?

[mtierney5]

The sensor in question I cleaned is located just to the right of the dip stick, poking out from under the Grey part of the engine cover at the front. You can see a black lead coming out from the harness that clips on the sensor just above the throttle body.

I also had a slightly sticking N75 valve but that was a pain to get too! That is located in the most awkward place on the rear side of the engine near to the turbo. Plenty of cuts and scratches when I did that!

Have you got the newest revision PCV valve and Diverter valve. I would check those too, as it could be an easy fix for you? Is your car standard or remapped? Plus is it under warranty? If it is under warranty I'd take it in to get fixed. You could also consider a pressure test to see if there are any leaks anywhere?

Thanks, its long gone from warranty im afraid!! Ya i have it remapped, why? I took off the sensor and i'll try to attach a pic of it, the copper looking wire loop looks black at the top, kinda burnt maybe.... no idea is this normal???? Is it?

Thanks.

[Ecomatt]

My car when on standard map wouldn't bring up the fault code. But when I installed the new map and the engine was working above OE parameters it bought the fault code up again. My sensor was burnt black too. Its when the oil recirculates via the PCV. It covers it in oil and then when it heats up and sticks to it. I took my PCV valve off an fitted a BSH revamp plate instead to stop the oil recirculating.

[Wallace_d]

Thanks, its long gone from warranty im afraid!! Ya i have it remapped, why? I took off the sensor and i'll try to attach a pic of it, the copper looking wire loop looks black at the top, kinda burnt maybe.... no idea is this normal???? Is it?

Thanks.

How do you disconnect the cable from the back of the sensor? There's a little clip on the side facing the dipstick, but it's not clear which way it needs to be pulled to release the connector.

Thanks.

[Ecomatt]

You pull the clip towards you. Sometimes you have to push the whole connector forward and then pull the clip to release it. Hope that helps?

[stever750]

I kept having this fault code rear its ugly head on me for a while now. The engine would sometimes be okay and then other days it would be underpowered. I checked the MAF sensor and that was working all in order. I checked all the boost hoses and vac hoses. They appeared all in order and I couldn’t see any obvious signs of damage or leaky joints. So I initially changed to the new revision diverter valve and took the car for a drive and the fault code came back. So I then changed to the new revision PCV valve and fitted it along with a new gasket. I could see that the valve was leaking and thought that was it. Or so I thought. I went out in the car for a drive and the fault code came back. I began thinking it might be the wastegate or something to do with the turbo. But then I had a moment of inspiration! I thought that it must be a sensor of some form that was giving incorrect readings. But I have no working knowledge of this engine, but thought they must all work pretty similar in design. Comparing it to my RS Focus and how that operated. I know the MAF sensor is fitted before the turbo. I thought there must be a sensor fitted after the intercooler to monitor boost pressure. I looked and saw a small sensor fitted above the throttle body and I proceeded to remove it. It was just held in by a torx screw. The sensor itself consisted of a metal wire hoop. Very similar to that of the MAF sensor. However it was covered in oil. The sensor is located near to where the PCV valve re-circulates into the inlet manifold. I got out my DX works brake part cleaner (also good for cleaning MAFs) Dowsed it heavily till all the oil film was dissolved and refitted. I took the car for a drive again and the engine instantly felt different. The was a lot more power and after a good drive of slow and fast driving. The fault code did not return. Happy Days!

I thought I would post my findings to help anyone else out there who is having the same problem as me.

Any chance of a series of pics?

I've got the dreaded repeat P0299 code so will need to work systematically through all the possible fixes, but it's only an intermittent fault

So far, I have a latest D rev DV valve (think it's D, might be G, anyway it's the non plastic sealed version)

New PCV and gasket

New Rocker cover, old one was broken and possible leaked a little around the filler neck.

I have had an intermittent MAF communication sensor fault too, but that's very recent. Have delayed fitting a new N75 valve, and want to eliminate any DIY fixes before spending any more more chasing this bloody dragon.

Symptoms are a random by journey ever so slight loss of top end power, at >4k RPM. Below this, the car feels pretty much the same whatever day of the week, above it's a lottery whether I get the full benefit of the remap or not. It's not a huge difference, just enough to be noticeable when trying to overtake slow moving traffic for example.

[bbowers]

I know this thread is so old, but I just wanted to say thankyou.  I've had the codes 0299 and 0101, I had replaced the DV as well as the PCV replacement kit. I had cleaned and changed the air filter and I was starting to lean towards a bad turbo.  I have cleaned the filter  and as you it was covered in oil, with the pcv delete kit I believe this won't be a problem in the future and am no longer having miss-readings when going full throttle and have not thrown a code since cleaning this sensor. 

 

Thank you!