zenica92

My 2008 Mercedes ML320 CDI displays P0408 code. I cleaned EGR valve and message is still there.

Maj. Dundee

Thanks for updating your profile.

Code P0408 cannot be found in M/B data codes. What is the name of your scanner?

zenica92

I do have AUYEL AL619.

Maj. Dundee

Zenica, your code reader is limited to only ECM and ABS and besides that it is still posting the wrong codes. There are no "P" codes for diesel engines. Only gas operated vehicles use "P" codes.

This is the that you should have bought.

zenica92

EGR code 2527-4- Signal line interrupted.
When I clean this code I can drive for hours nothing happening, but when I shut of engine and restart the code is back.

I am skeptical the EGR is defective?

Maj. Dundee

When you you try to restart the eng. is there any specified amount of time that the code appears. Is it any time or when the eng. is cold.

Did you ever get code 2045 Crankshaft Sensor?

zenica92

EGR code coming back instantly (no delay) for cold or hot engine.

I never got 2045 code.

Maj. Dundee

Try removing & installing the elec. connector to the MAF sensor.

zenica92

Yes I did but nothing is changed.

Maj. Dundee

Well, I wouldn't be to anxious to buy a new positioner ($450). The code specifies that the signal wire (Gray/Yellow) is the problem. You should trace the 3 wire harness from the positioner to the ECM to see if that wire is damaged.

zenica92

Could you provide any electrical diagram what can help me to trace the conections

Maj. Dundee

Go to the bottom segment 36-37 and find EGR Positioner Y27/9. Gray/Yellow wire goes directly to the CDI Cont. Module, conn. #1 wire #71

zenica92

Finally, I had chance to work on issue.

There is no grey-yellow wire on connector but Red-green instead.

When I measure there is 12 V (red-green wire) when the engine is turn on and the power getting to zero after is turn of.

I am not sure should power on this wire be permanently on or not.

zenica92

Maj. Dundee

You say that there is no Grey/Yellow wire. Then what is this wire color from your own photo?

zenica92

OK, if this wire going straight to the CDI and signal is interrupted, could problem be at CDI.

Maj. Dundee

I doubt it is the CDI Module. This code tells you that the wire itself or the pin at the connector or the pin at the EGR is causing the problem.

Why are you concerned about the RED/GRN wire losing power when you shut off the eng.? Be concerned when there is no voltage while the eng. is running, which is not occurring.

Monitor all three wires while the eng. is running, Red/Grn for 12 v, & Brn for GROUND with a DVOM. Check each wire for at least 30 sec. to see that you never lose the voltage or ground.