Brand new EGR valve fitted - still getting code P042F

[sushilovin]

TL;DR: Bought brand new EGR valve to pass MOT after doing without one for the past year. Focus mk2.5 TDCi engine misfires at low RPM, medium load and goes limp. Runs perfect with EGR disconnected, but won't pass MOT like that. Have tried disconnecting battery to reset PCM and used Forscan reset learned values procedure with no joy.

I made some forums posts about a similar issue close to a year ago on this forum. Since then, I've learnt a lot more about the operation the EGR system and turbo and feel like I'm in a much better place to attempt to diagnose this issue.

My car is a 2010 Focus 1.6 TDCi. I bought the car in a bad shape, turbo and EGR issues. I eventually got the turbo to work correctly without replacing any parts (although I did replace the boost control solenoid for peace of mind) but I'm still struggling with the EGR.

For most of the last year, I've just driven the car with the EGR valve unplugged. Yes, I've had an engine management light on that entire time, but I just lived with it because the engine was otherwise running just fine. The only reason I've come back to this issue is because of an upcoming MOT in mid-August, giving me around 2 weeks to try and resolve this issue.

I bought a brand new EGR valve from a company that supplies the local garages at the cost of £170 including VAT, and fitted it with the battery disconnected to reset the PCM in that time. Fired up the car after around 20 mins of disconnecting the battery and took it for a drive with my laptop in the passenger seat. Seemed to be driving well until I tried to accelerate at low RPM with a medium load. The engine sounded like it was missing every other cylinder, though it wasn't as rough as when it would misfire with the old EGR valve. Read the codes when I got home to find it had a "Pending" P042F, EGR valve stuck closed.

Parked up and ran the Forscan EGR relearn procedure, and continued driving, but this didn't fix the issue. In fact, I reckon it may have made it worse. 

The next day, disconnected the battery again for around an hour, then took the car out to meet some mates. After a few misfires, the car turned down the VGT, so I had essentially no boost. It struggled over every slight incline, and I had to downshift to first to get up a hill you could reasonably take in third. On the way back from that outing, I unplugged the EGR valve before leaving and the car was absolutely perfect the whole way back. For some reason, simply having the EGR plugged in causes misfires which makes the car go into limp.

Unfortunately, despite personally being happy to run without an EGR, I need to get this sorted for the MOT. It will fail with an engine light, and it will fail if they spot EGR is disconnected (which also throws an engine light). I'm at a loss for the cause. My best guesses are electrical or a blockage in the EGR cooler or DPF, but I don't really understand why either of these things would cause it to misfire ONLY when the EGR is plugged in. I have gathered some data in Forscan which, I believe, shows the EGR position and EGR commanded position don't match, even after the service procedure, but I'm not entirely sure what to do about this. Perhaps there is a short in the wiring harness causing it to read dodgy values.

I'm at a loss and desperate to get this sorted before the MOT. If I'm lucky, perhaps I can just clear codes in the morning and hope it gets through! Any help would be massively appreciated. Cheers.

[Tizer]

I believe the original ones fitted by Ford were Valeo ones and I've heard a lot of people say that other aftermarket makes don't work very well. It might be a good idea to dismantle the old one completely, clean it, refit it and do the learning procedure again to see if the problem is still there. 

[sushilovin]

3 hours ago, Tizer said:

I believe the original ones fitted by Ford were Valeo ones and I've heard a lot of people say that other aftermarket makes don't work very well. It might be a good idea to dismantle the old one completely, clean it, refit it and do the learning procedure again to see if the problem is still there. 

I believe the one that was fitted in the car when I bought it was already aftermarket. The previous owner said he had had it replaced, but there are no receipts to prove it. I removed the top part containing the motor and cleaned the bottom before buying this new one. The old one moved freely for the most part, but the sliding rail wasn't able to settle all the way at the top of the slot. I'm not sure if this is just how they're designed or if that particular one has a manufacturing defect. I'll inspect and compare them both and see what I find. Thanks for the suggestion :)

[sushilovin]

Haven't had a chance to have a nosy yet, and it's absolutely pouring it down here today. With the help of the Mk2.5 schematics diagram in the pinned thread on this forum, I've now found the wires that connect to the EGR valve and their purpose. I'll get my multimeter tomorrow, weather permitting, and check for a short or unusual resistance on those lines. Using that diagram, should the worst come to it, I'm wondering if I can just connect the wires in the right way to trick the ECU into thinking the EGR is functioning perfectly. Not sure about the feasibility of this thought. I just need this old s**tbox to get through the MOT!

[Vladek]

I had a similar problem about 4 years ago with my focus mk 2.5. I tried changing the EGR valve with a brand new OE one at a Ford dealer and it still gave me errors and limp mode. They tried changing it with a used original one that was working on another Focus and it was the same. After that I tried a new aftermaket (Valeo) one and it worked just as bad. Finally decided to do a software delete for the EGR and car is still running perfectly after 60k km. No check engine, no codes, nothing.

2 years later the dealer contacted me that they might have found the issue. They wanted to replace the ECU and a couple other modules and wires. The cost would have probably been more than the value of the car and I doubt this would have fixed it.

Long story short, it seems like the easiest fix is to delete the EGR via software and enjoy the car.

[sushilovin]

22 minutes ago, Vladek said:

I had a similar problem about 4 years ago with my focus mk 2.5. I tried changing the EGR valve with a brand new OE one at a Ford dealer and it still gave me errors and limp mode. They tried changing it with a used original one that was working on another Focus and it was the same. After that I tried a new aftermaket (Valeo) one and it worked just as bad. Finally decided to do a software delete for the EGR and car is still running perfectly after 60k km. No check engine, no codes, nothing.

2 years later the dealer contacted me that they might have found the issue. They wanted to replace the ECU and a couple other modules and wires. The cost would have probably been more than the value of the car and I doubt this would have fixed it.

Long story short, it seems like the easiest fix is to delete the EGR via software and enjoy the car.

To be honest mate, that's exactly what I'm thinking of doing. Just concerned about the cost of it, I mean I've just spent almost 200 on a new valve, just to spend probably around the same amount to delete it? However, it is a possibility that has been on my mind since I first had this issue. Have you had any issues with getting it through the MOT after the delete or with DPF regen? I'm not sure mine has been regening properly since unplugging the EGR but I reckon it's worth a shot. Cheers for the suggestion, I'll call around some remap shops :)

[sushilovin]

I decided to do some further testing this evening as I can't do anything else until tomorrow. Checked the LL_EGRV PID which says whether the EGR parameters are learned or not. I took it for a test drive while it was "Not Learned", suffered misfires and clearly wasn't right. Took it home, connected the laptop and ran the relearn procedure. Did the same drive but the readouts don't look right from FORScan and it seemed to still be misfiring.

The misfiring suggests to me something is wrong with the air-fuel ratio, not enough oxygen to combust, perhaps due to too much exhaust gas reentering the cylinder? However, I noticed something else on the graphs in FORScan. I have attached an image below. The PIDs are RPM, Desired RPM, LL_EGRV, EGR_PCT (the commanded position) and EGRVP (EGR Valve Position). 

You can see at idle RPM, they look OK. Still a margin of error, but not too bad. Then if you look at the places the engine is revved, you can see the graphs pretty much mirror each other. I don't know if this is standard behaviour or if I've got some crossed wires giving the opposite readout from the sensor. Going to have a look around this forum and see if anyone else has an image of both graphs in the same screenshot.

I did gather some tests from a proper test drive, but I forgot to save it before stopping the collection and lost the data. After about 5 test drives around the estate, I decided I had enough.

Not sure if this is useful data to anyone, but if you notice anything or think I should be collecting more data, I'd be glad to hear it. I'm taking the car to work tomorrow so we'll see if any more DTCs come up then.

Cheers for the help so far :)

[Vladek]

The EGR is closed anyway during hard acceleration and that's when they measure the exhaust gases opacity. I had no issues getting through MOT as deleting EGR (properly) will not increase exhaust smoke. Deleting the EGR increases NOx emissions, but they do not measure gases composition for diesels (only gasoline engines get tested like that).

I have no issues with DPF regens and I do not think there will be any if the ECU thinks everything is good with the EGR. I heard that the lifespan of the DPF increases after deleting EGR, but I have no clear data to support this claim. I noticed that the DPF differential pressure decreased compared to 4 years ago so that is a sign that the filter is living a good life after the EGR delete. 

The only 2 obvious differences after deleting the EGR was way greater torque when accelerating at low rpm (1000-1300 rpm) and less engine heat when driving in town. Previously the engine compartment was super hot after driving especially in heavy stop and go traffic and it also smelt like burnt plastic. Now it just gets up to temp without any smells or excessive heat.

I paid about 70 EUR for the software delete, but please note that I am not from the UK so the prices might be different. Having a new valve that closes perfectly should help when deleting the EGR as you won't need a blanking plate or any physical modifications to the car.

[Tdci-Peter]

1 hour ago, sushilovin said:

You can see at idle RPM, they look OK. Still a margin of error, but not too bad. Then if you look at the places the engine is revved, you can see the graphs pretty much mirror each other. I don't know if this is standard behaviour or if I've got some crossed wires giving the opposite readout from the sensor.

It looks a bit like an electrical problem to me. The last blip on the throttle seems to give a sensible waveform, PCT drops to about zero as soon as the rpm rises, and valve position falls to a stable value (though not 0). Both signals stay that way until rpm falls, and PCT shoots up briefly to make the valve open again.

But on previous blips it is completely different. Position signal just drops to a value below the stable value for the last blip, and PCT shoots up during the blip as if the valve has closed too far and it is trying to get it back to the position it was happy with on the last blip. It is a bit like a poor connection or even open circuit on the valve position line, and it is drifting about unpredictably. Every time the position drops below a certain value, PCT just shoots up to full.

Ideally I would try to get a multimeter reading from the position feedback signal, and compare it with the Forscan position reading while holding rpm steady at various values, to see if they stacked up, or if the Forscan position reading just kept drifting about. Though I know doing that is easier said than done!

I am a bit surprised the ECU has been doing DPF regens with an indicated fault on the EGR, the EGR is used to some extent during the regen. I think it has to be closed (max O2 to burn the extra fuel needed to heat up the DPF), but am not 100% sure. A proper software delete needs to leave the regen system operational.

 

 

[sushilovin]

On 8/8/2021 at 9:31 PM, Vladek said:

The EGR is closed anyway during hard acceleration and that's when they measure the exhaust gases opacity. I had no issues getting through MOT as deleting EGR (properly) will not increase exhaust smoke. Deleting the EGR increases NOx emissions, but they do not measure gases composition for diesels (only gasoline engines get tested like that).

I have no issues with DPF regens and I do not think there will be any if the ECU thinks everything is good with the EGR. I heard that the lifespan of the DPF increases after deleting EGR, but I have no clear data to support this claim. I noticed that the DPF differential pressure decreased compared to 4 years ago so that is a sign that the filter is living a good life after the EGR delete. 

The only 2 obvious differences after deleting the EGR was way greater torque when accelerating at low rpm (1000-1300 rpm) and less engine heat when driving in town. Previously the engine compartment was super hot after driving especially in heavy stop and go traffic and it also smelt like burnt plastic. Now it just gets up to temp without any smells or excessive heat.

I paid about 70 EUR for the software delete, but please note that I am not from the UK so the prices might be different. Having a new valve that closes perfectly should help when deleting the EGR as you won't need a blanking plate or any physical modifications to the car.

Good to know! I've had the EGR unplugged for a good while, and I reckon it does perform slightly better with less lag at very low RPMs, but it's not a huge difference.

A local bloke who does tuning in the evenings quoted me at £120, but when I went there tonight, he wasn't able to do it with his kit, something about Ford changing the software on a Bosch ECU? I've got another garage looking at it tomorrow for £150, so hopefully they can do something with it. I do like that the engine gets up to temperature faster when the EGR is connected, not too keen on running a cold engine for too long, but it's a sacrifice I'm willing to make. I think the old valve was fine at sealing and probably alright in general, but I assumed a new one would fix it... clearly not! Thanks for your messages :)

On 8/8/2021 at 11:46 PM, Tdci-Peter said:

It looks a bit like an electrical problem to me. The last blip on the throttle seems to give a sensible waveform, PCT drops to about zero as soon as the rpm rises, and valve position falls to a stable value (though not 0). Both signals stay that way until rpm falls, and PCT shoots up briefly to make the valve open again.

But on previous blips it is completely different. Position signal just drops to a value below the stable value for the last blip, and PCT shoots up during the blip as if the valve has closed too far and it is trying to get it back to the position it was happy with on the last blip. It is a bit like a poor connection or even open circuit on the valve position line, and it is drifting about unpredictably. Every time the position drops below a certain value, PCT just shoots up to full.

Ideally I would try to get a multimeter reading from the position feedback signal, and compare it with the Forscan position reading while holding rpm steady at various values, to see if they stacked up, or if the Forscan position reading just kept drifting about. Though I know doing that is easier said than done!

I am a bit surprised the ECU has been doing DPF regens with an indicated fault on the EGR, the EGR is used to some extent during the regen. I think it has to be closed (max O2 to burn the extra fuel needed to heat up the DPF), but am not 100% sure. A proper software delete needs to leave the regen system operational.

 

 

Glad to see you here Peter, you're a name I recognize from last time I posted. I reckon it might be electrical too. I saw a comment on this post (that you also commented on, lol) about a bit of silicon in the ECU connection. With the headless security bolts I've heard about secure the ECU, I'm not sure it's something I want to investigate myself, but you're definitely right about how erratic it is. Sometimes the graph looks fine, other times, they're completely out of sync. I'll get a screenshot of some data on an actual drive later this evening, I'm not sure how useful data gathered while just blipping the throttle actually is. I'll also double check the garage I'm visiting tomorrow will keep the regen system working. I appreciate the help, I'll update this message shortly with some more data.

EDIT with data:

Unfortunately my only bluetooth laptop that can connect to my OBDII reader is at work, so I've had to use my phone. It's a horrible screenshot, but I've focused on a particularly interesting bit that happened while I was pulling onto a mini roundabout. The app on my phone doesn't have PIDs for EGR_PCT and EGRVP, so I've used EGR_ERROR, which is the difference between the two previously mentioned PIDs.

 

If you look very closely at RPM, you can see where the engine is misfiring right at the point that the EGR error is around 60% (it usually fluctuates between 100% and -100%, presumably due to a tiny amount of latency).

I don't think this data actually shows much, and it's all a bit of a moot point anyway because it's being deleted at 10am tomorrow...

I think if anyone finds this thread in the future looking for advice, the advice is... just get it deleted. Don't throw money at it trying to fix it like I have. I wish I had just spent the money to get it deleted months ago instead of trying to get it working and saved myself the headache and cash. This is a poorly designed system that, in cars of this age, only causes issues. You only need to search "egr" on this forum to see that. Good luck to anyone trying to fix this.

[Tdci-Peter]

3 hours ago, sushilovin said:

I saw a comment on this post (that you also commented on, lol) about a bit of silicon in the ECU connection. With the headless security bolts I've heard about secure the ECU, I'm not sure it's something I want to investigate myself, but you're definitely right about how erratic it is. Sometimes the graph looks fine, other times, they're completely out of sync.

With Focusoap, it seemed to be an electrical connection problem between ECU & EGR feedback pot, also. It can be a nightmare locating electrical problems in a car wiring loom even with 40+ years of electrical experience, and some half decent equipment. Without either, it will be next to impossible. Many garages struggle, they can do very difficult & complex mechanical jobs, but for electrics they rely on some "magic" bit of kit, that may or may not give the right answer.

I can't say much from the phone pictures, those wild swings look wrong, but without throttle position & valve position it is not possible to make any real conclusion.

A software change to keep it closed may be the simplest option to keep the car on running, and avoid yet another premature scrapping of a vehicle, With 50% of the total environmental damage done by a car being in the manufacture & disposal (some say), early scrapping does more harm than an EGR delete.

[sushilovin]

Intended to post Wednesday night after getting the car back, but I've been busy.

The EGR delete went OK. Like the first guy I visited, the garage also couldn't program my ECU through the OBD port, so they charged an extra £70 for a total of £220, to get the car up, remove the passenger wheel, wheel liner, open the ECU and program it directly from the circuit board. Far more expensive than I was expecting, but after getting the car back, I'm pleased with the results. My phone app reckons the EGR is still open 25% all the time, but the EML is finally off and the car runs better than ever. Drove it for around 30 miles that evening and probably another 20-30 the next day with the EGR still connected, and no EGR DTCs or EMLs!

It's been in another garage for its' MOT today. Passed with no problems, just a few minor advisories you would expect from a car of this age. I'm delighted, I think it's the first MOT I've ever had where the garage didn't call me until it was finished. Pretty chuffed.

Despite this, I'm sorry to betray you all, but I'll be selling the car shortly to get myself a petrol with more power. I will make sure to notify the buyer of the rough past it's had, my conscience won't allow me to do otherwise. I'm done with diesel emissions equipment games. DPFs, EGRs, the whole lot is horrible (although smoky diesels are gross too, so it isn't all bad I suppose).

Thanks for all the help posted in here, I appreciate the engagement. Cheers!

[jon cooke]

Has any one replaiced the five cables from the ecu/pcm which supply the egr. that would be my next step and to cut the harness open and to check for damaged wiring. However I know that the veichle electrics were run open circuit by the previous owner, no main body earth which fried the main positive supplying the fuse box and burnt out the diode pack in the back of the alternator. So I do suspect the ecu/pcm has been spiked

[Tdci-Peter]

19 hours ago, jon cooke said:

Has any one replaiced the five cables from the ecu/pcm which supply the egr.

Have you found the Focus wiring diagrams posted on this site?

Sadly, I don't much like the possibility that the car may have been used either without a battery or with a major earth missing. Current & Voltage surges from the alternator could have damaged some of the electronics. Car electronics is supposed to be designed for this sort of abuse, at least on paper, but there are always weak points in such a complex system.