EGR P0402
Question: which component sets this code? Is it the EGR or a sensor in the system? Is there a way to test the EGR? Is this code related to the EGR failing to close all the way? What is the component next the EGR that looks like a temp sensor? (screws into the same exhaust duct as the EGR)
The EGR is easy to replace but I don't know the system well enough to say that the problem is the EGR and not something else. I appreciate any help or advice you can give. I think this must be an easy problem to solve.
2008 E320 bluetec, 110,000 miles.
Question: which component sets this code? Is it the EGR or a sensor in the system? Is there a way to test the EGR? Is this code related to the EGR failing to close all the way? What is the component next the EGR that looks like a temp sensor? (screws into the same exhaust duct as the EGR)
The EGR is easy to replace but I don't know the system well enough to say that the problem is the EGR and not something else. I appreciate any help or advice you can give. I think this must be an easy problem to solve.
2008 E320 bluetec, 110,000 miles.
Likely causes for that include a bad vacuum hose, if it is a vacuum-actuated EGR, or a dirty or worn EGR valve. For excessive flow to be the problem, I doubt that other passages in the system are blocked, because that would cause a lack of flow, not too much flow, I suppose.
Disassembling the EGR and cleaning it can help and check movement of the pintle and diaphragm, along with cleaning the port it fits into, but you shouldn't spray solvents on the diaphragm (so your carb cleaner may not necessarily have been the best thing to do.)
I can't say much more than that.
Haynes' "OBD-II & Electronic Engine Management Systems" book, ISBN 1 56392 612 1, is a good reference for more detail. Your local parts store probably has a copy for about US$20
Can I test the proper operation of the EGR valve?
My system is electronic - no vacuum hoses.
The cleaning helped me get over a year out of it but now needs to be replaced. I'm going to replace it myself since it is pretty straight forward and on top of the engine.
2008 E320 Bluetec
130,000 miles - runs like a champ!
The cleaning helped me get over a year out of it but now needs to be replaced. I'm going to replace it myself since it is pretty straight forward and on top of the engine.
2008 E320 Bluetec
130,000 miles - runs like a champ!







