Bad MAF / no code

2005 Sprinter 3500 SHC 2.7L w/ 92,000 miles:

Has anyone ran across a situation where there is no code for a a bad MAF causing a 50% load calculation at idle but it does induce a P0402 for escessive EGR flow? Interesting....
I would have caught it sooner if the EGR wasn't cracked in the upper shaft where the servo meets the lower portion causing it to go past close to partially reopen again.

ppm.ross.lee said:

2005 Sprinter 3500 SHC 2.7L w/ 92,000 miles:

Has anyone ran across a situation where there is no code for a a bad MAF causing a 50% load calculation at idle but it does induce a P0402 for escessive EGR flow? Interesting....
I would have caught it sooner if the EGR wasn't cracked in the upper shaft where the servo meets the lower portion causing it to go past close to partially reopen again.

Click to expand...

I can't offer specific experience or advice, but since nobody has responded...

The mass air is monitored/calculated using more components than the MAF sensor proper. I know from reading and experience that Mass Air DTC's can be set by related problems with the MAF sensor itself, EGR, Boost Pressure Sensor, O2 Sensor, Intake Air Temperature Sensor and probably a couple others I don't recall off the top of my pointy little head. The ECM algorithm (loosely correct term here?) has only so many Air Mass codes it can set. It must happen that sometimes the closest DTC that can be applied is spit out. If I understand your situation/question correctly then my guess is that in your case the EGR problem was noticed and that triggered the closest DTC available. I'm no expert so I defer to more informed input. vic