T7 308 2.0 HDi EGR valve stuck?

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Fellow Frogger
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Hopefully you'll all had a good xmas and break so far

We noticed our (T7 308 2.0 HDi with 213K on the clock) car was slow to accelerate, so I popped by a local non dealership garage today who specialises in Euro cars and he ran a scan with their Autel scanner. This picked up the following codes

P0402 'Intermittant' air circuit quality of cold ai below the setting
P0488 'Intermittant' refer service manual (but I looked up and it says EGR Throttle Position Control)
P0490 'Intermittant' EGR valve position incorrect (too closed)
P0409 'Intermittant' EGR valve detected jammed closed during ECU switching to dormant phase

The current conclusion without further diagnosis is the EGR valve is stuck closed. He advised this is not a critical issue and we can continue to use the car until the issue is resolved as long as we don't mind extra emissions

Questions

1. Can the car be used without risk for the present as advised?
2. In a post here it is said that a stuck EGR valve can be verified by disconnecting the EGR sensor (on the EGR valve housing) as the performance issue should stop. Is that recommended? if so I found that that sensor is in an extremely difficult place to access and I'm not sure whether I can disconnect (without removing various pipes) and if I did remove I'm not sure whether could get it back on (is there an easy method or alternative diagnosis that can be done?)
3. Should I replace with a new valve or get one from a wreaker (a 2nd hand one could risk the same issue again dependin go the age of the donor car)

Any suggestions or advice appreciated
 
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Some of those codes are saying that unexpected electrical values are being received by the engine computer from the EGR valve or the air/EGR ratio is wrong. They all come down to the same thing - P0409 the EGR valve is blocked (or stuck on the closed position when it shouldn't be).

P codes starting with 0 are standardised OBD codes, not Peugeot specific.

A car with no valve faults can run with a blocking plate fitted, but runs more smoothly if it is merely restricted with a hole in the plate.

Which engine is in the car, the RHR or RHH? (See letters 6.7.8 in the VIN). The former's valve is at the rear of the engine; the latter's is an electrically driven affair at the front.
 
@seasink thank you for the reply

It has the RHR engine. I think I maybe able get my small hand back there to disconnect the EGR valve sensor connector without removing pipes but a) will that verify the valve is the issue by causing the car to run normal b) would that work anyway if the valve is stuck closed?
 
If you have access to the PSA diagnostic software there are forced test procedures for the EGR valve and the air metering valve on the front of the engine, to listen to their sounds.

You could try the blocking plate, plenty of people have done it. The EGR codes will remain, If not satisfactory get the valve out.

This end is the solenoid valve.

egr.jpg
 
@seasink

Thank you for the reply I don't have the PSA diagnostic software but what I wanted to try is to disconnect the solenoid valve connector (you can see I circled that in red). I read with that disconnected the car should not experience the lag in acceleration as the car ECU will not try to correct or respond to the stuck valve?

Can you advise whether that is something I could try to diagnoise the issue, if the lag disappears that allows me use that either a temporarily fix whilst I consider sourcing a valve or even leave it (but I'm not sure what the consequences of that would be but it appears nothing other than more emissions?

I found I get to that connector without removing anything with my small hand although somewhat blind. It appears the connector does not have a clip to release if I go by pictures, is that the case i.e. I can just gently pull out?

image_2023-01-21_124527048.png
 

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The ECU will report yet another error and the valve will still be stuck. If it were my car I'd remove it and clean it. A mirror will show the fixings.

The lag may be coming at the doseur end of the system, it's giving error P0402. Have a look at the state there
 
@seasink again thank you for the reply :)

I'm currently assuming it is stuck and therefore the performance issues (and codes), and that disconnecting the sensor will verify a stuck valve, if the the car still exhibits lag on acceleration as you say the issue could be elsewhere. I'll try and disconnect that sensor tomorrow

What is "the doseur end of the system" what is that and what should I look for in regards to "state"
 
If you drop fixings or gasket fiddling with the EGR valve you may have some fun retrieving them. Pack a rag or similar back there.

The doseur is a valve arrangement under vacuum control located near the number 9 in your diagram above. It regulates both fresh and recirculated intakes. The vacuum is turned on or off by the ECU. The valves should be working and the tubes should have no splits or damage that would remove vacuum..
 
seasink said:
If you drop fixings or gasket fiddling with the EGR valve you may have some fun retrieving them. Pack a rag or similar back there.

The doseur is a valve arrangement under vacuum control located near the number 9 in your diagram above. It regulates both fresh and recirculated intakes. The vacuum is turned on or off by the ECU. The valves should be working and the tubes should have no splits or damage that would remove vacuum..
Click to expand...

@seasink Thank you again for the reply. I won't take the valve off just try and disconnect the sensor ('c' on my diagram) which is on its cable but I'll be careful! (assuming it comes out easy it appears to be the same 5 pin style used on the rear lamp housing). It will be interesting to see if it provides a warning on the console without that sensor connected.

Thank you too I'll check those tubes around 9 on my diagram too for leaks and spilts
 
@seasink ok I fully disconnected that EGR sensor.

1. no error msg comes up on the console as someone reported in the UK would occur (at least with a 1.6)
2. The car runs but it appears hestitation on acceleration was worse esp. on a hill from stop
3. There is no easily visible damage to any tubes

Maybe I have a partially blocked EGR, is that possible?
 
All

  1. If I use a 2nd hand EGR valve (cleaned and with 3 months warrenty) should I ensure a new EGR valve circuit seal is used (part 1618 32)?
  2. Would an EGR cleaner such as offered by Penrite etc possibly clean the valve to allow function as it should i.e. should I try that first?
 
A quick update. I had the EGR valve replaced with a 2nd one one. I have the old EGR valve and can see the mechanical spring loaded actuator gets stuck half way i.e. did not freely moved from open to closed without using my finger to move. I may try cleaning and see if that frees it up and keep as a spare. Interestingly the carbon build up was not excessive (at least to my eyes)
 
Don't be fooled, I just blocked the egr on the RHY, egr itself was sticky like yours and stuck ope = very bad. The big issue is crap in the inlet it causes with blow by from the cylinders, the muck in the inlet is disastrous. I would strongly suggest you are in for a surprise if you look.
 
Matthew said:
Don't be fooled, I just blocked the egr on the RHY, egr itself was sticky like yours and stuck ope = very bad. The big issue is crap in the inlet it causes with blow by from the cylinders, the muck in the inlet is disastrous. I would strongly suggest you are in for a surprise if you look.
Click to expand...
Thank you for the reply. When you say look, look specifically where?
 
A scope up the air inlet on back of engine, not simple / possible for most to do but what was done on mine, inlet off and cleaned!
 
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