Mercedes ML270/2001/CDi/WDC1631132X740267- ERG Fault - Lacks power - P1403Archived Message
Posted by Simon Forsey on June 3, 2004, 5:32 am
This vehicle was looked at by the workshop for some time before I was called in,the car was lacking power and was hesitant on the pedal, they had fully service it and had given up.
Using my AD Pro I extracted fault code P1403 (EGR Negative Control Variation] When the EGR was disconected the car had better power and the hesitance disappeared. The garage didnt want me to go any further and against my advise ordered and fitted a new EGR Valve.
They called me back today and with a bit of a deeper look I found that on live readings the EGR was being held open at 95% when it was hesitant, however when it came down to 3% it still lack power but didnt hesitate. Using a scope I found the pattern to the EGR was doing what the ECU asked.
My question is, what tells the ECU to open the EGR that far, I cant find any sensor faults and all appears well. Is there any common problems of this kind on these vehicles.