hollisda
SDD Junior Member
I have a ’06 F250 with a 6.0L that has begun throwing DTC P0404 (EGR circuit range) & P0405 (EGR position sensor circuit low), typically at highway speeds under medium to heavy acceleration. After the requisite four starts without a fault, the MIL goes off (but the codes are still stored.) I can drive the truck for many miles or days without throwing a code (MIL off), depending on how hard it is driven. I’ve cleaned the EGR valve but it really wasn’t sticky and this did not help. (Actually not for sure if it is throwing the code under acceleration or perhaps just after I ease off of the throttle; need to verify this.)
About the same time that the truck started throwing the P0404 and P0405 codes, it started experiencing a stumbling and black smoke under light acceleration, again at moderate to highway speeds. If I step down harder on it, the boost comes up, the power returns and the smoke stops. It does not throw an associated code for the faltering and smoking. (Stepping down on it will occasionally precipitate the throwing of the P0404/P0405 code but not always.)
I’m thinking that perhaps the VGT actuator is sticking. This could account for the P0405 code due to excessive backpressure on the EGR, especially under deceleration, and would account for the loss of power and smoke under light acceleration; i.e. impeding the proper spooling up of the turbo.
Does this sound feasible? Anyone else experience this phenomenon? Any other ideas as to the root cause for both problems?
Thanks for any ideas or suggestions.
About the same time that the truck started throwing the P0404 and P0405 codes, it started experiencing a stumbling and black smoke under light acceleration, again at moderate to highway speeds. If I step down harder on it, the boost comes up, the power returns and the smoke stops. It does not throw an associated code for the faltering and smoking. (Stepping down on it will occasionally precipitate the throwing of the P0404/P0405 code but not always.)
I’m thinking that perhaps the VGT actuator is sticking. This could account for the P0405 code due to excessive backpressure on the EGR, especially under deceleration, and would account for the loss of power and smoke under light acceleration; i.e. impeding the proper spooling up of the turbo.
Does this sound feasible? Anyone else experience this phenomenon? Any other ideas as to the root cause for both problems?
Thanks for any ideas or suggestions.
