Technical Fault code P0404 EGR

[Les Holloway]

Hi

I,ve just been using the Multiscan and for the second time this fault shows up.

The EGR is blanked off any ideas?

Also the air intake quantity readings are wildly different the actual being 528, the desired being 282 a MAF problem?

 

[Davren]

P0404 = Exhaust Gas Recirculation Circuit Range/Performance

The fault code is probably showing because your EGR valve is blanked.
.

 

[momoe]

The EGR fault is probably showing because the EGR valve is stuck, although there's no flow through the system the valve can still get stuck (Especially if the valve isn't cleaned while blanking).
Could be a solenoid issue, IIRC, you can get the solenoid off without removing the EGR itself, you can then check the solenoid itself.

The intake air quantity could be a MAP or MAF sensor, MAF tells it what's going in, MAP tells it what it's actually getting.
Try whipping the MAF out and cleaning it, electrical contact cleaner is good or chuck it in a container with methylated spirits and shake vigorously!
If that doesn't work, try take the MAP out and cleaning that, often the sensor hole gets blocked with gunk.

Davren,
I'd expect a little more help from a moderator, anyone who's blanked an EGR on a JTD knows that you don't get an error. You certainly don't get an error because you blank it.
I know there's an 'official' line on blanking which is fair enough, your post doesn't imply this and is simply flippant.

 

[Davren]

With the EGR valve fully blanked, the JTD 8 valve engines record the fault code but don't illuminate the EML. JTD 16 valve engines record the fault code and illuminate the EML.

This has been discussed many times in Stilo section of the forum, and tested on my own Stilo JTD 8v. With an EGR valve blanking plate fitted, it records the code. Without the the blanking plate, it doesn't.

With the genuine Fiat "swirl plate" (blanking plate with 3 small holes in it) fitted, the code is also not recorded.

No "official" line, no flippancy, just the results of testing.
.

 

[momoe]

Not in my own experience on 90k on two JTD 115's, a 52 and 55.

I used MultiEcuScan for some time and before that an OBDII reader, I cleaned and blanked EGR's on both cars and I didn't have any 0404 logged errors anytime I used either system.
Still trying to work out how the the 0404 is triggered, if the valve is working correctly how does the ECU know the EGR pathway is blanked?

If anyone in the Multi community has seen these, I'm happy to accept that I'm misinformed and my apologies for the flippancy remark.

Ironically, your second post should have been your first, folks like as much information as practicable to help them understand the issues.

 

[martyc5674]

Mine is blanked... No error. Jtd 115.

I can't see how it could record a code due to blanking unless there's an airflow meter in there.
It does record a code if sticking which could happen regardless of being blanked.

Maybe the stilo has some other sensor/ way of knowing.
Marty.

 

[Kevin Bisschops]

Hi my name is Kevin.

This is an interesting topic.

The aswer is partially given.

When the ERG valve opens a part of the combustion air will be exhaust gas.
This means that the MAF sensor would need to measure less air when the EGR valve is actuated.

The engines volumetric efficiency is mapped so for any given rpm and boost the ECU knows the amount of air sucked it. When the egr valve opens this amount of air should be less then the mapped value since exhaust gas is being recirculated under higher pressure then the boost pressure (delta p over engine !!! that's why you have diesel engine with throttle valves in the inlet, it makes you capable of lowering the amount of fresh air and run more ERG)

The MAF sensor makes the engine capable of estimating how much fresh air is sucked in. With ERG blanked the ECU will see:
fresh air with open EGR valve = fresh air with closed ERG valve
--> makes it capable of setting the fault)

Now the sice part:
You can fool the ECU if you lower the signal voltage of the MAF sensor when the ERG valve is actuated.

You can to this by activating a transitor with the egr-valve signal and bypass 2V of the MAF signal over a resistor. This way the ECU will think the valve is working.

ps: for give me for my mistakes in English. My native language is Flemish/Dutch.