P045B Exhaust Gas Recirculation “B” Control Circuit Range/Performance
OBD-II Trouble Code Technical Description
Exhaust Gas Recirculation "B" Control Circuit Range/Performance
What does that mean?
This diagnostic trouble code (DTC) is a generic powertrain code, which means that it applies to OBD-II equipped vehicles with an Exhaust Gas Recirculation system. Vehicle brands may include (but are not limited to) Land Rover, GMC, Chevrolet, Dodge, Chrysler, Ford, Toyota, Honda, etc. Although generic, the specific repair steps may vary depending on make/model.
The EGR (Exhaust Gas Recirculation) system’s purpose is to redirect exhaust gas back into the cylinders. Since exhaust gas is inert, it displaces oxygen and fuel, thereby lowering cylinder temps, which, in turn, lowers oxides of nitrogen emissions. For that reason it needs to be carefully metered into the cylinders (via the EGR valve) so as not to adversely affect the engine’s performance. (Too much EGR and the engine won’t idle).
If you have a P045B, then the EGR valve is likely an electrically controlled EGR valve instead of a vacuum controlled EGR valve. Also, the valve will usually have a feedback system built into it that informs the PCM (Powertrain Control Module) what position the valve is in; open, closed, or somewhere in between. The PCM needs to know this to determine whether or not the valve is operating as needed. If the PCM determines that the valve should be operating, but the feedback circuit shows that the valve is not open, this code will set. Or if the PCM determines the valve should be closed but the feedback signal indicates that the valve is open, this code will set.
Refer to a vehicle specific repair manual to determine which is the "B" EGR circuit in your particular case.
Potential Symptoms
There may be no symptoms of a P045B trouble code other than the MIL (malfunction indicator lamp) or check engine light.
However, Exhaust Gas Recirculation systems are inherently problematic due to carbon buildup in the intake manifold, etc. This normal buildup can lodge in an EGR valve, holding it open when it should be closed. If this is the case, the engine may idle rough, or not at all. If the valve has failed and is NOT opening, then symptoms would be higher combustion temps and as a result, higher Nox emissions. But the latter symptoms aren’t going to be noticeable to a driver.
Causes
Usually this code points to either carbon buildup or a bad EGR valve. However that doesn’t rule out the following:
Possible Solutions
If you encounter this trouble code, we encourage you to refer to a vehicle specific repair guide for your particular year, make, model and engine. The following information is more general in nature. Be sure to also check for TSBs (technical service bulletins) that may apply to your vehicle.
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"Delete Error Code Permanently, Disable DTC Error Code Function for p045b in the ECU"
In extreme cases, we even have the option to permanently remove the specific DTC p045b 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 p045b.