Technical Description of OBD-II Trouble Code
The range/performance of the Exhaust Gas Recirculation Cooler Bypass Control Circuit is being affected.
What does that mean?
This is a generic powertrain diagnostic trouble code (DTC) that is applicable to many OBD-II vehicles (1996-newer). This includes vehicles from various manufacturers such as Ford, Dodge, Ram, Jeep, Chevrolet, Volkswagen, Mercedes, etc. Although it is a generic code, the specific repair steps may vary depending on the year, make, model, and powertrain configuration of the vehicle.
OBD-II trouble code P245B and related codes P245A, P245C, and P245D are associated with the Exhaust Gas Recirculation (EGR) cooler bypass control circuit.
The purpose of the EGR cooler bypass control circuit is to open and close the EGR bypass valve under specific conditions in order to prevent the EGR cooler from becoming overloaded. This prevents fouling, which can negatively impact the performance and efficiency of a diesel engine. The Engine Control Module (ECM) monitors the operation of this circuit by receiving voltage references from the EGR temperature switch and other components. In most configurations, the EGR cooler bypass valve returns the exhaust gases to the intake for combustion. The location of the EGR bypass valve, EGR cooler, temperature switch, and associated components varies depending on the vehicle manufacturer.
When the ECM detects improper voltage or resistance outside of the normal expected range within the exhaust gas recirculation cooler bypass control circuit, it will set code P245B and illuminate the check engine light, service engine soon light, or both.
A typical EGR cooler bypass valve:
What is the severity of this DTC?
The severity of this code can vary from moderate to severe depending on the specific symptoms of the malfunction and the condition of the cooler and bypass valve. A malfunctioning EGR valve or control circuit can cause excessive ignition and pre-ignition, which may result in damage to the pistons, valves, and other internal engine components.
What are some of the symptoms of the code?
Symptoms of a P245B trouble code may include:
What are some of the common causes of the code?
Causes for this P245B code may include:
What are some P245B troubleshooting steps?
The first step in the troubleshooting process for any malfunction is to research the Technical Service Bulletins (TSB’s) for the specific vehicle based on the year, model, and power plant. This can save time by providing guidance in the right direction.
The second step is to locate all components associated with the EGR cooler bypass circuit and visually inspect them for physical damage. This circuit may include several components depending on the specific vehicle, such as the temperature switch, bypass valve, EGR valve, EGR cooler, and ECM. Check the associated wiring for defects such as scraping, rubbing, bare wires, or burn spots. Also, check the connectors and connections for security, corrosion, and damaged pins. This inspection should cover all wiring connections to all components, including the EGR temperature switch and the ECM. Consult the specific technical data for the vehicle to confirm the configuration of the EGR cooler bypass valve control circuit and identify all components incorporated within the circuit, which may include a fuse or a fuse-able link in some cases.
Advanced Steps
The advanced steps are specific to each vehicle and require advanced equipment for accurate performance. These procedures involve using a digital multimeter and referencing the specific technical data for the vehicle.
Voltage Checks
The reference voltage and acceptable ranges may vary depending on the specific vehicle and circuit configuration. The troubleshooting charts and sequence provided in the technical data will assist in making an accurate diagnosis.
If this process reveals the absence of a power source or ground, continuity testing may be necessary to check the integrity of the wiring, connectors, and other components. Continuity tests should always be performed with the power removed from the circuit, and the normal readings for wiring and connections should be 0 ohms of resistance. Resistance or lack of continuity indicates faulty wiring that is open, shorted, or corroded, and it must be repaired or replaced.
What are some common repairs for this code?
Common Mistake
We always recommend seeking professional mechanical service to address this issue. However, if that is not possible, we offer the option to permanently delete this specific DTC. All other codes will continue to be addressed. If you are interested in this option, please upload your ECU file to our portal.
