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Air Circuit and EGR Fault Finding |
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ThoreT
 
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  Member No: #4807
Location: Voyenenga |
My 2.7 HDI suffers from power loss and uneven running during acceleration. Prime suspect is of course an EGR valve. I connected my code reader to check running parameters. See attached pictures. There are three different parameters related to each EGR. The rear EGR Valve Position 1 Setting (Rear) is stuck at 50%, regardless of power-setting. I guess this means the rear EGR valve is physically stuck at 50% open. The two other values, EGR Valve Control 1 (Rear) and EGR Valve Position 1 (Rear) both follow power-setting in a sensible way, and drop to around 5% after one minute at idle. One of the values I'm sure refers to the input value from the ECU, what but is the third parameter? I would think there would be only two parameters, one for input value and one for actual physical EGR valve position. The picture showing Air Flow parameters shows a low rear air flow, which makes sense. Strangely, I get no fault codes for the EGR, only messages related to low airflow and airflow incoherence. Also, when I ran the EGR actuator check in Diagbox, I got no error message, but I could not hear the valve clicking. Hopefully a new rear EGR will get me going again....    |
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C6Dave
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   Member No: #1
Location: Northumberland |
Did you change the rear EGR valve? | ||
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ThoreT
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Member No: #4807
Location: Voyenenga |
I've not changed it yet, but obviously will do.Mainly wondering what the three values pertaining to the EGR valve actually describe. The 50% value must be the actual physical position.... | ||
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MGmike
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  Member No: #3151
Location: South Queensferry |
I think you have a turbo actuator fault on the rear turbo. All EGR faults I've seen report an error and I think the 50% setting may be a software bug reporting 10x the actual. Symptoms of a turbo actuator error are:- 1, Loss of power (limp mode) without errors logged 2, Possibility of an error for air flow correlation putting the EML on (usually under hard acceleration) 3, Low air flow measured from the rear MAF sensor 4, Eventually, a Turbo boost control error but without an EML! I have one with these exact symptoms and after deleting the correlation error many times, it has eventually reported the actuator error during a 100 mile trip at the weekend. I'll be attempting the actuator repair soon as per a previous post (do a search). |
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321dave
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Member No: #614
Location: Dublin |
Hi Mike, I think I might also have the turbo actuator issue. Mine has no EGR codes but has lumpy running and airflow 2 code is registered and a code for a differential between the MAFS sensors. No code but when I Rev to over 2500rpm it triggers the airflow codes. I have no Turbo code at the moment. I have two new Valeo EGRs fitted with new cooler flasks as well! |
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MGmike
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Member No: #3151
Location: South Queensferry |
321dave wrote ... I think I might also have the turbo actuator issue. Mine has no EGR codes but has lumpy running and airflow 2 code is registered and a code for a differential between the MAFS sensors. Usually the actuator issues don't cause any lumpy running. In your case, I would swap the MAFs over to see if the fault/error moves. 321dave wrote ... No code but when I Rev to over 2500rpm it triggers the airflow codes. I have no Turbo code at the moment. I have two new Valeo EGRs fitted with new cooler flasks as well! Is this revving whilst stationary or on the move? If stationary, the turbo isn't really doing anything and therefore unlikely to be an actuator issue. If when moving the actuator could be the cause but the vanes in the turbo could also be sticking. Either way you'll need to remove the actuator to confirm which one is the source of the problem. |
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321dave
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Member No: #614
Location: Dublin |
Thanks Mike, i will try the MAF switch about. The lumpy running is only when accelerating for example which is effecting the gear change quality as well at the moment. The engine runs fine when stationary and revs well, but noticed that when revving to say 2500rpm it will introduce the two codes P010E flowmeter signal 2 (front) & P010F Air flowmeter signals. Changed for a brand new battery as well last week as strange codes were starting to appear fairly often. I did a smoke test also last week as i was thinking i had an intake air leak. It did show up two areas of smoke leakage. 1. The oval sectioned pipe join near the fuel filter. 2. The front turbo intake pipe rubber seal (this is down by the radiator) pipe going into intake of the turbo. I will re-run the smoke test again. Maybe a Turbocharger Boost Leak Tester kit might be the best way to test for a leak though. |
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cruiserphil
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 Member No: #38
Location: Celbridge |
Hello 321Dave, Sue was reporting something similar a good while ago, particularly when the engine was cold. I experienced it once or twice but it would go away for a timer. Eventually the car did flag a fault and it pointed to the rear egr valve. Ended up having the EGR's mapped out and all good since!! Best regards, Phil C. |
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321dave
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Member No: #614
Location: Dublin |
cruiserphil wrote ... Hello 321Dave, Sue was reporting something similar a good while ago, particularly when the engine was cold. I experienced it once or twice but it would go away for a timer. Eventually the car did flag a fault and it pointed to the rear egr valve. Ended up having the EGR's mapped out and all good since!! Best regards, Phil C. Hi Phil, that sounds very interesting. I will go and re-check the rear EGR valve. When Sue was driving was the engine smooth and then suddenly jumped and then would be fine? I have alot of hesitation when driving and changing gears. It just happened recently as I replaced both EGR valves and went for new cooler flasks as well. I was having some white smoke issues from the exhaust pipe and a dropping coolant level as well. But I found the leak eventually after using a pressure testing kit on the system and replaced one little pipe leading to the front EGR flask. So most likely I disturbed something around the EGR’s while I was working. I smoke tested it and found a lot of smoke coming from the turbo intake pipe where there is a rubber seal? One EGR valve was new from Citroen (expensive) and the other was bought from EBay half price. |
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cruiserphil
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Member No: #38
Location: Celbridge |
Hello 321Dave, Yes, the jumping would only appear for a few seconds. I was quite rough. It felt like the fuel being cut off intermittently Best regards, Phil C. |
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321dave
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Member No: #614
Location: Dublin |
cruiserphil wrote ... Hello 321Dave, Yes, the jumping would only appear for a few seconds. I was quite rough. It felt like the fuel being cut off intermittently Best regards, Phil C. Hi Phil, That’s exactly the same problem i have! It is rough and the though crossed my mind that i had a problem with the high pressure fuel pump. But no serious codes when i checked. Just the P010E & P010F. I’m wondering now if it’s the harness on the new EGR or the new EGR is actually faulty? But if it was faulty surely it would show a EGR fault code? Did you have any codes come up relating to the EGR when you did a scan? |
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321dave
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Member No: #614
Location: Dublin |
A interesting turn. I ran a Top scan bluetooth tool I bought recently on a special function to bi-directionally control the turbo actuators and suddenly got these two code faults turn up after the test. P004E & P0247 I could hear the rear sounded ok, but the front turbo was clicking or clacking not well and kept going as if something wasn’t closing or opening well. So now my hesitation while driving is pointing to the front turbo in particular having an issue with the P0247 code it seems. Both new EGR valves are clicking fine and show no codes when tested Any thoughts on what is best to do next. |
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C6Dave
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Member No: #1
Location: Northumberland |
321dave wrote ... A interesting turn. So now my hesitation while driving is pointing to the front turbo in particular having an issue with the P0247 code it seems. Any thoughts on what is best to do next. Well P0247 definitely points to the front actuator  P004E was not listed by Citroen but online I found: Check the turbocharger/supercharger: remove the intake to check the turbo/supercharger for damage or debris. If damage is found, replace the unit. Test the position/pressure sensor and circuit: in most cases, the position sensor should have three wires going to it: power, ground and signal. |
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321dave
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Member No: #614
Location: Dublin |
Thank Dave for you help. I have the same list of downgraded modes as well as the list you posted. I’ll need to definitely investigate the front turbo. |
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cruiserphil
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Member No: #38
Location: Celbridge |
Hi Phil, Did you have any codes come up relating to the EGR when you did a scan? Hello 321Dave, EGR codes did not appear for quite a while but eventually did! Best regards, Phil C. |
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