P0400 Exhaust Gas Recirculation Flow Malfunction
OBD-II Trouble Code Technical Description
Exhaust Gas Recirculation (EGR) Flow Malfunction
What does that mean?
This diagnostic trouble code (DTC) is a generic powertrain code, which means that it applies to OBD-II equipped vehicles. Although generic, the specific repair steps may vary depending on make/model.
The exhaust gas recirculation (EGR) valve is vacuum controlled valve that regulates the amount of exhaust gases that re-enter the cylinders.
The powertrain control module (PCM) determines how much based on engine load, temp, and other conditions. If the PCM detects that the amount of exhaust gases entering the cylinder were insufficient or non-existent, this code is set.
Symptoms
No symptoms will likely be noticed by the driver other than the MIL (malfunction indicator lamp). However, non visible symptoms will be increased combustion temperature and increased Nox emissions.
Causes
A code P0400 may mean that one or more of the following has happened:
Possible Solutions
Since EGR valve designs are different, no one test will suffice:
Related EGR codes: P0401, P0402, P0403, P0404, P0405, P0406, P0407, P0408, P0409
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Let us fix your problem. You are most welcome our diagnosis experts have in most cases the knowledge and skills to find the cause of the error code p0400 and to solve the problems.
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"Delete Error Code Permanently, Disable DTC Error Code Function for p0400 in the ECU"
In extreme cases, we even have the option to permanently remove the specific DTC p0400 and disable the function of the specific error code in the ECU. All other fault code functions will then continue to work to protect the engine. This is different from clearing an error code with a diagnostic device. We have the option to permanently remove the function of the specific error code, so that it never comes back. Also emergency running that occurs on the specific error code can be solved in most cases.
Of course we prefer to first try to solve the cause of the error code, but sometimes the only solution is to permanently disable the DTC function of p0400.