P1408 fault code analysis and how to clean the egr valve system
P1408 fault code and how to check the egr valve system including how to clean the egr valve exhaust internal flow.
P1408 engine egr valve out of test range and why you need a clean egr valve
This fault code P1408 is an egr (exhaust gas recirculation) valve circuit failure. If you get this fault code, try removing and cleaning the egr valve pintle rod but at the same time, clean the port opening of the egr port where the egr valve is mounted.
If possible, clean the passage going downstream from the port up to the throttle body. Using an air blower, the passage can be blown and soaked with carb cleaner spray to remove the build up carbon which restrict the exhaust gas passages.
On some engine models, it is necessary to remove the upper intake manifold to access this port openings. A step by step procedure will be given to you if you are a member of ATS. This process is simple by nature but garages will charge you a lot because it is labor extensive.
On most engine models, an egr valve cleaning is the obvious route when you see this P1408 fault code but replace egr valve if it has a lot of mileage. This is due to the fact
that cleaning the egr valve will take more time and there is still the possibility of failure later on. This is especially true if you have remove the intake manifold already and the cost to replace the egr valve is not too expensive compared to having a clean egr valve when you buy it brand new.
If you are working on newer Ford engines, it require the replacement of dpfe sensor before replacing the egr valve. DPFE stands for "Delta Pressure Feedback of EGR"
and it monitors the differential vaccum pressure in order to measure the exhaust gas flowing to the egr valve. The
difference in vacuum is then sent as a signal to the ecm to control the egr valve valve openings.
On some models like egr Ford Focus system, the dpfe is known to fail if the engine has symptoms like misfiring and hesitation. To verify the dpfe sensor, check the solenoid wirings attached to it and measure the supply and ground voltage. Again, if deciding whether to replace the dpfe sensor or the egr Ford focus valve, the latter must be replaced first as part of your engine maintenance especially if it shows up as a P1408 fault code. But remember that egr valve cleaning is one way to verify if the code is a serious or permanent code.
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