P245B Exhaust Gas Recirculation Cooler Bypass Control Circuit Range / Performance

P245B Exhaust Gas Recirculation Cooler Bypass Control Circuit Range / Performance

OBD-II DTC Datasheet

EGR Cooler Bypass Control Circuit Out of Range / Performance

What does this mean?

This is a Generic Powertrain Diagnostic Trouble Code (DTC) applicable to many OBD-II vehicles (1996 and newer). This may include, but is not limited to, Ford, Dodge, Ram, Jeep, Chevrolet, Volkswagen, Mercedes, etc. Despite the general nature, the exact repair steps may vary depending on the model year, make, model and transmission configuration. ...

OBD-II trouble code P245B and associated codes P245A, P245C, and P245D are associated with the EGR cooler bypass control circuit.

The purpose of the EGR cooler bypass control circuit is to open and close the EGR bypass valve under predetermined conditions to prevent EGR cooler overload, known as plugging, which affects the performance and efficiency of a diesel engine. The engine control module (ECM) monitors this circuit by receiving reference voltages from the EGR temperature switch and other related components to control the EGR cooler bypass valve, which returns exhaust gases to the combustion inlet in most configurations. The location of the EGR valve, EGR cooler, temperature switch and related components varies from vehicle to vehicle and varies greatly from manufacturer to manufacturer.

When the ECM detects an abnormal voltage or resistance outside the normal expected range on the EGR cooler bypass control circuit, a P245B code will set and the check engine light, engine service light, or both lights may illuminate.

Typical EGR Cooler Bypass Valve:

What is the severity of this DTC?

The severity of this code can vary greatly from moderate to severe, depending on the specific symptoms of the problem and the level of chiller and bypass valve performance. A defective EGR valve or control circuit can cause excessive ignition and pre-ignition of the engine, which can damage pistons, valves, and other associated internal engine components.

What are some of the symptoms of the code?

Symptoms of a P245B trouble code may include:

• Engine May Fail Emissions Test
• Ignition ringing or knocking during acceleration
• Increased fuel consumption
• Poor engine performance
• Service engine light will be on soon
• Check engine light is on

What are some of the common causes for the code?

Reasons for this P245B code may include:

• Exhaust gas recirculation cooler bypass valve defective
• Clogged or damaged exhaust gas recirculation cooler
• Temperature switch malfunction
• Excessive carbon build-up
• Faulty or damaged wiring
• Corroded, damaged or loose connector
• Defective ECM

What are some steps to troubleshoot the P245B?

The first step in troubleshooting any problem is to review the vehicle-specific Technical Service Bulletins (TSBs) by year, model, and powerplant. In some cases, this can save you a lot of time in the long run by pointing you in the right direction.

The second step is to locate all components associated with the EGR cooler bypass circuit and examine them for obvious physical damage. Depending on the specific vehicle, this circuit may include several components, including a temperature switch, bypass valve, EGR valve, EGR cooler, and an engine control unit. Perform a thorough visual inspection to check the associated wiring for obvious defects such as scratches, abrasions, exposed wires, or burn marks. Next, check the connectors and connections for security, corrosion and damage to the contacts. This process should include all wiring connections to all components, including the EGR temperature switch and engine control unit. Consult the specific vehicle data sheet to check the configuration of the EGR bypass valve control circuit and to confirm each component included in the circuit, which may include a fuse or fusible link in some applications.

Advanced steps

The additional steps become very vehicle specific and require appropriate advanced equipment to be performed accurately. These procedures require a digital multimeter and vehicle-specific technical reference documents.

Voltage test

The reference voltage and allowable ranges may vary depending on the specific vehicle and circuit configuration. Specific technical data will include troubleshooting tables and appropriate sequence of steps to help you make an accurate diagnosis.

If this process detects that a power source or ground is missing, a continuity test may be required to verify the integrity of wiring, connectors, and other components. Continuity tests should always be done with power disconnected from the circuit and normal readings for wiring and connections should be 0 ohms of resistance. Resistance or no continuity indicates a wiring fault that is open, shorted, or corroded and needs to be repaired or replaced.

What are the standard ways to fix this code?

• Replacing the exhaust gas recirculation cooler
• Replacing the EGR cooler bypass valve
• Replacing the temperature switch
• Cleaning connectors from corrosion
• Repair or replace faulty wiring
• Cleaning carbon deposits
• Flashing or replacing ECM

General error

• Replacing the EGR cooler bypass valve when carbon build-up or faulty wiring causes the ECM to set this code.

Hopefully the information in this article has helped point you in the right direction to troubleshoot an EGR cooler bypass control circuit DTC problem. This article is for informational purposes only and specific technical data and service bulletins for your vehicle should always take priority.

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