egr and engine management

[splitpin]

Hi guys,
how does the egr system work on a '99 V 406 110 HDi? can it bring on the engine management fault light?
I think I may have a faulty EGR solenoid. Does it work on the over-run?
The reason I ask, is that after descending a short hill on over-run, the engine management fault light came on and it struggled to rev to 3000.
This is the 2nd time this has happened in the last 2 weeks. The 1st time the management light went out suddenly until it came back on today.
Any ideas?
Cheers, Graham.

[Doggy]

It's very difficult to tell what the problem is as there are so many potential causes. The egr system is fairly unlikely as HDi's will run with leaky egr valves - it just makes them a bit smokier.

The only egr related fault the ecu can detect is if the solenoid valve is not connected as it checks for continuity prior to starting the engine.

(For this reason owners wishing to disable the egr generally do it by disconnecting / plugging the vacuum pipe from the solenoid to the egr valve).

Can't be certain, but I'm fairly sure the egr on operates, on a variable duty cycle, with the 'throttle' fully closed, as you can see this on live data via PP2000.

Intermittent EML can have many causes, inluding throttle position sensor, fuel rail pressure sensor, crank sensor, MAF, MAP or just good old fashioned bad coonections / poor earthing.

It's also 'normal' for the EML to go out again with an intermittent fault - it has to go through either 3 or 5 'journeys' without the fault occuring in order to clear.

The only real options are to get it diagnosed, or if it's not really doing any harm, wait, watch and maybe stumble on an answer......

[splitpin]

I have already swapped both Cam & Crank sensors.
I have most other sensors to hand, if required.
I had to repair the Turbo control solenoid as I had very little or no boost. I swapped it for the EGR control valve.This is why I have rightly or wrongly assumed it might be the egr control valve.
Cheers,
Graham.

[splitpin]

Hi, I have changed the following sensors, Crank, Cam, Boost Pressure, Fuel Rail. The only ones I haven't changed are the one on the High Pressure Pump and Coolant Temp.
The EML seems to be coming on more often now.
When the engine is cold, if you descend a hill on over-run, the EML will come on.
When the engine is hot, if you climb a hill and load the engine the EML will come on.
If you stop, switch the engine off for a short time, then re-start, the EML will stay on but the engine will have performance back.
It may go off after a while, or the fault may re-occur.
Any Ideas Anyone????
Cheers,
Graham.

[Doggy]

The only way to find out for certain is to read the fault codes, ideally with Peugeot Planet or one of the clones. I think if you were going to find the answer by substitution, you'd probably have got there by now.....

If you post your location, someone nearby may be able to help.