Error Code P049A: What It Means & What To Do?

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To understand this error code set by your car, you have to know about the system that’s related to it. Code P049A is about the Exhaust Gas Recirculation (EGR) system of your vehicle. The components of the EGR system are the EGR Valve, Engine Control Module (ECM) interchangeably also known as PCM, Controlled Vacuum Switch Valve or EGR Solenoid and an EGR Vacuum Modulator. The ECM controls the EGR solenoid which operates the EGR Vacuum Modulator. This Modulator regulates the opening and closing of the EGR Valve making the system work well.

A step motor is installed in the newly manufactured vehicles. This motor controls the flow rate of the EGR from the exhaust manifold, and has four winding phases. The output pulse signal from the ECM leads the operations of the motor. Two windings are turned On and then Off in sequence, and every time the on pulse is issued, the EGR valve opens/closes which changes the flow rate. If the vehicle doesn’t desire any change in the flow rate, no pulse signal is issued by the ECM. For the valve to maintain position at any particular opening, a fixed voltage signal is issued.

What causes this problem with Exhaust Gas Recirculation B Flow?

There are several causes for the OBD Error P049A to occur, following is a list:

• Damage of the DPFE, MAP or MAT Sensor
• DPFE hose or hoses may be cracked or have collapsed
• EGR valve or related Sensors may be open or even short circuited.
• Carbon Clogging in the EGR passage
• Faulty EGR Volume Control Solenoid valve
• EGR Temperature Sensor and Circuit damaged
• Bad electrical connection of the EGR Volume Control Solenoid Valve

1. EGR Temperature Sensor - It works with the EGR solenoid, and may require repair or replacement if not functioning as needed.
2. EGR Volume Control Solenoid - The engines efficiency depends on the optimal functioning of the EGR Volume Control Solenoid, check if it can be repaired, otherwise replace it at Parts Avatar with assured quality deliverance.
3. DPFE sensor or MAP Sensor - The Manifold Absolute Pressure sensor, is a significant part of your engine, don’t delay repairing or replacing it depending upon its condition.
4. DPFE hose - Differential pressure feedback EGR is an integral part of the EGR system. If you need a replacement, Part Avatar will ship it to you, we deliver to the remotest corners of Canada!
5. EGR Valve - Replace your EGR valve at Parts Avatar by ordering online.

Below is a list of common symptoms to be observant of:

• Decrease in the performance of engine
• Unwantedly rich or lean exhaust
• Delay in the engine start-up compared to usual
• Considerably low fuel efficiency
• Engine Light being ON or Service Engine Soon Warning Light showing
• Increase in the consumption of fuel

You may be wondering how you could possibly correct this error on your own, or have the knowledge to understand and explain to your mechanic the issue you’re facing. We break it down for you, so that you can be more informed about your vehicle and the error code P049A.

Locate the valve and try to access it, it may be easier to do that in certain car models than others, use your car manual for assistance in locating it. For replacing, unbolt the old valve and proceed with installing the new one. You may notice rust gathering on the nuts/bolts, in such case you would have to use penetrating oil before you attempt to remove the valve.

The exhaust components call for more cautiousness, they can be hot and complicated to handle. Ensure there’s no carbon build-up in the EGR passages. And again, make sure you use the penetrating oil generously prior to removing any rusty nuts/bolts. Check to see if the EGR passages are clear, do this only when the valve is off. Inspect the vacuum hoses and/or electrical connectors attached to the EGR, if they need repair or replacement do that too before you replace your EGR.

Remember that the EGR is a system, if any one part also doesn’t work the whole system will fail to perform efficiently. You can find all relevant parts, for an array of vehicle models at Parts Avatar.

Now that you have understand the problem, it’s time to diagnose it correctly, here are the diagnostic steps:

• Begin by locating the vehicle diagnostic connector, retrieve all the stored codes with the use of a scanner, record these accurately. You may need them in the future as the diagnosis continue. Once you’ve done that, take your vehicle on a test-drive and observe if the code is reset immediately.
• Get hold of a diagnostic scanner, a digital volt/ohmmeter (DVOM), and any reliable vehicle information source if the error code P049A is stored right after clearing the codes.
• Now, proceed to visually inspecting the EGR system. So basically, the EGR valve and all related wiring and connectors. Spend extra time on the wiring harnesses routed near the hot exhaust manifolds and the jagged edges that are associated with exhaust shields.
• Be safe and prevent controller damage, for this you will have to disconnect all related control modules from the circuit prior to testing resistance/continuity with the DVOM.
• The scanner can then be used to manually activate the EGR system. Majority EGR systems will require a certain rate of speed for them to automatically be activated. You can use the wiring diagrams and connector pinout graphs. These can be found in your vehicle information source. Now, test each EGR valve connector circuit with the help of the DVOM.
• There may be few circuits that do not conform to the manufacturer’s specifications. Don’t panic, simply follow them back to the source, which usually will be the PCM connector and retest them. If the PCM gives no output signals, suspect a malfunction of the PCM or the PCM programming having an error. If you find any open/short circuits in the process, you will have to either repair or replace them depending on the severity.
• To test the actual EGR valve and the sensors related for checking appropriate flow, you will need the DVOM. Again, your vehicle information course will provide you the details on how to test these parts. If you observe that the step-down EGR valve or any other related sensors are not as per the manufacturer’s specification, they will have to be replaced.

Common Mistakes When Diagnosing the P049A Code

• EGR valve has failed
• Powertrain Control Module (PCM) has failed
• Wiring is exhibiting issues