Would Faulty Manual EGR Valve have an error code

[J.T.Fox]

Evening all,
My 2003 C5 2.0 HDi has been playing up, lack of power, lost 10mpg of the urban average, lots of black smoke out the exhaust etc.

Local garage diagnosed faulty MAF from the error code.
I replaced the MAF no change.

Having studied the forum I've disconnected the vacuum pipe from the maual EGR valve and this have improved.

There's no cable at the EGR so would it have an error code?
The vacuum pipe has suction present at tickover, could this mean the control valve's goosed?

Many thanks

[alden]

Im led to believe you can strip and decoke it, however its a short term fix. mine c8 snapped completly off and thus total loss of power.didnt do it myself as it is located at back of engine. and on the c8 thats a hell o a place to get to. relplaced complete valve and no probs.

[CitroJim]

It's worth checking the Intercooler on a C5. They do seem to like leaking. Have a look at it and if the bottom is soaked in oil then likely it's leaking.

Thing is, a leaky intercooler will fool the MAF sensor and result in all the symptoms you describe, including smoke. The EGR may be a red herring...

[DickieG]

There's no cable at the EGR so would it have an error code?

Yes it can as the MAF sensor/ECU measures the airflow into the engine so if the EGR valve is say open or closed all the time the ECU gets an illogical reading which triggers a fault and the ECU to go into limp home mode, whether this occurs on a particular car often depends upon which version of software the ECU is running on.

Re the MAF sensor you fitted, was it a genuine part? I ask as many people have discovered that spurious MAF sensors don't work correctly.

[J.T.Fox]

Thanks to all who've replied.