Technical Description of OBD-II Trouble Code
Control Circuit for Exhaust Gas Recirculation “B”
What does that signify?
This diagnostic trouble code (DTC) is a generic powertrain code that applies to vehicles equipped with an Exhaust Gas Recirculation system and compliant with OBD-II standards. Various vehicle brands, including Land Rover, GMC, Chevrolet, Dodge, Chrysler, Ford, Toyota, Honda, etc., may have this system. The specific repair steps may vary depending on the make and model of the vehicle.
A vacuum solenoid controls the Exhaust Gas Recirculation (EGR) system. The solenoid receives ignition voltage. The Powertrain Control Module (PCM) controls the vacuum solenoid by grounding the control circuit or driver.
The driver’s primary function is to provide ground for the controlled object. Each driver has a fault circuit that the PCM monitors. When the PCM activates a component, the control circuit voltage is low or close to zero. When the component is deactivated, the voltage on the control circuit is high or near battery voltage. The PCM checks for these conditions, and if it doesn’t detect the proper voltage at the appropriate time, it sets this code.
The EGR system is used in engines to reduce combustion temperature, thereby reducing emissions. Consult a vehicle-specific repair manual to determine the specific “B” EGR circuit in your case.
Potential Symptoms
Typically, a fault in the control circuit does not cause noticeable symptoms other than the illumination of the Malfunction Indicator Lamp (MIL). However, if the EGR control solenoid is stuck open due to debris or other factors, the code may be accompanied by misfire under acceleration, rough idle, or engine stalling.
Causes
The causes for a P045A EGR code could be any of the following:
Possible Solutions
If you encounter this trouble code, we recommend referring to a vehicle-specific repair guide for your particular year, make, model, and engine. The following information is more general in nature. Also, check for any applicable TSBs (technical service bulletins) for your vehicle.
With the ignition on and the engine off, use a scan tool to activate the EGR solenoid. Listen or feel for a clicking sound, indicating that the solenoid is operating.
If the solenoid operates, you’ll need to check the current draw on the ground circuit. It should be less than one amp. If it is, then the problem is intermittent. If it isn’t, there is excessive resistance in the circuit, and you should perform the following steps:
1. When it’s activated, try blowing lightly through it. If you can’t, there may be a blockage causing excessive resistance. Replace the EGR solenoid as necessary. If there is no blockage, disconnect the EGR solenoid and the PCM connector containing the EGR solenoid control circuit. Use a digital Volt-Ohm meter (DVOM) to check the resistance between the control circuit and battery ground. It should be infinite. If it isn’t, there is a short to ground on the control circuit. Repair the short to ground and retest as necessary.
2. If the solenoid doesn’t click as it should, disconnect the EGR solenoid connector and connect a test light between the two wires. Use the scan tool to command the EGR solenoid on. The light should illuminate. If it does, replace the EGR solenoid. If it doesn’t, perform the following steps: a. Check for 12 Volts on the ignition supply voltage to the solenoid. If it isn’t present, inspect the supply circuit for an open or a short due to chafing or breakage and retest. b. If it still doesn’t operate, manually ground the EGR solenoid control circuit. The light should illuminate. If it does, repair the open in the EGR solenoid control circuit and retest. If it doesn’t, replace the EGR solenoid.
