2012 mercedes sprinter 3.0

2012 merdeces sprinter .P049d egr a control position exceeded learning limit. Permanent code will not eraise. Egr has 5 pin connector. Pin. 1 motor ground, pin. 2 motor 12v. Pin 3. Egr potentiometer 5v, pin. 4 sensor ground. Pin 5. Sensor signal.
All pins have the right voltage and signals as expected, At computer & egr connector. So im confused on what the issue is. The only thing i noticed was that with key on engine off and connecter disconected there is no 5v at the signal wire, but key on engine off with the connector connected i do have signal coming from egr, also egr motor is pwm. Another weird thing i noticed is with the key on engine off looking at live data, egr actiual possition and egr computer demand is way off and egr correction is 16%. With the key on engine running the live datat on egr actual position and egr demand match perfectly. At first i though the egr was clogged by carbon deposit but once removed there was no carbon deposit just regular sooth, still cleaned it but no change . I hope this makes sense. Forgive for all the bad spelling, but i need help.thank you

This is a Control Position Fault !

Can the EGR motor be activated ? Does it move SMOOTHLY through its complete range ?

If so then do you have a good 5v & Ground at the sensor potentiometer ?

As the EGR Flap moves from end to end does the Signal Wire reflect that without any Glitches ?

The 5v & Ground should be tested at EGR and the Signal should be tested at ECU.

I would expect the sensor wire to range from approx. 0.6v to 4.4v.

Using a Scope would be the only accurate way to do this as it will pick out glitches that a DVM will not.

An Amp Clamp on EGR Actuator & Voltage on Signal Wire will paint you a great 3D Picture.

George Uk wrote:

This is a Control Position Fault !

Note; this may have 2 EDR valves - High & Low Pressure ?

Can the EGR motor be activated ? Does it move SMOOTHLY through its complete range ?

If so then do you have a good 5v & Ground at the sensor potentiometer ?

As the EGR Flap moves from end to end does the Signal Wire reflect that without any Glitches ?

The 5v & Ground should be tested at EGR and the Signal should be tested at ECU.

I would expect the sensor wire to range from approx. 0.6v to 4.4v.

Using a Scope would be the only accurate way to do this as it will pick out glitches that a DVM will not.

An Amp Clamp on EGR Actuator & Voltage on Signal Wire will paint you a great 3D Picture.