P0409: Exhaust Gas Recirculation Sensor "A" Circuit

[CircuitChaos]

Hi,

I drive a Renault Trafic II 2.0 dCi 115, made in 2009. Most probably it's a M9R engine.

It reports a fault code P0409 („Exhaust Gas Recirculation Sensor "A" Circuit”) – that's what I see in Torque, the mechanic saw 040975 in his computer. It's been this way since I bought it, and I drove it normally for two years, just ignoring the „Check Engine” light. I've read it's just a dirty EGR valve and it's enough to clean or replace it to get rid of this fault code.

Recently I had a leaky radiator and went to the workshop to replace it. I asked the guys to replace the EGR valve as well, and they did. But the fault code didn't go away – it reappears shortly after cleaning the codes.

I started playing and disconnected the EGR valve. A new fault code appeared: P0487 („Exhaust Gas Recirculation Throttle Position Control Circuit”), which makes much more sense, as the valve has five pins – two are for the motor driving the butterfly valve, and three for the (probably Hall-type) sensor, reporting the valve angle back to the ECU.

So the valve seems fine. The one removed from my car also seems fine (it's dirty, but seems to be operational, at least it doesn't get stuck when I apply voltage to it).

Anyone else had this problem? Where to look next? What is this „Sensor "A" Circuit”? I looked at the EGR diagram and couldn't find any sensors (there's an air damper valve just before the EGR, with the same feedback sensor, but disconnecting it produced other fault codes).

[Sync0r]

I have the same fault code in my Megane MK2 Renault sport 175 2.0 dci. I'm trying changing the egr temp sensor, this worked previously so hopefully works again, sensor arrives today, will let you know.

[Axa]

Did you find any solutions to this problem?
I got the same P0409 (EGR sensor sircuit A) on my 2007 Espace 2.0dci ( M9R)
It have been intermittent for a few years, but now it seems like the code comes right back after clearing it with my iCarsoft reader.
I have removed the metal clips around the oval plastic lid on the EGR sensor. And everything inside looks good. Tried to secure the cables a bit more in case the problem was a broken cable.
I'm surprised I can't find anything specific on whats usually is causing the P0409.
I'm not interested in replacing the EGR as the car is not worth the costs, and also runs fine for a good while even with the code. And when going into "limp home" mode, it runs fine again after deleting the code.

[CircuitChaos]

I have the same fault code in my Megane MK2 Renault sport 175 2.0 dci. I'm trying changing the egr temp sensor, this worked previously so hopefully works again, sensor arrives today, will let you know.

Hello after a few years. How was the result?

Did you find any solutions to this problem?

No, sadly not. And you (now, after two years)?

I gave up then, but since then AI tools gained traction, so I decided to revisit the issue and ask our new AI overlords for a solution.

AI claims (I don't know if correctly) that this DTC means that the feedback signal from the EGR is outside of a „reasonable limit”, and points at some loose contact in the plug or problem with the wire harness (broken or intermittent wire). It says, specifically, that it's not the „miscalibration” code, like in some other cars. But you know, AI can hallucinate, so I don't trust it fully.

I'll try opening the plug and cleaning the contacts, and maybe also soldering the wires directly to the pins (maybe it's a loose crimped contact?). Maybe this helps. If not… I truly don't know what to do other than accept the DTC and the fact that the car runs perfectly fine despite it (and that it will be harder for me to sell it when I finally decide it's time).

I'm not interested in replacing the EGR as the car is not worth the costs, and also runs fine for a good while even with the code. And when going into "limp home" mode, it runs fine again after deleting the code.

Does it go into limp mode because of that code? In my case it doesn't, it runs fine. I had limp mode once because of a broken stop pedal sensor so I know I'd recognize the difference.