P0404 Mercedes-Benz Code - Exhaust Gas Recirculation Circuit Range/Performance
Quick Answer
Early Exhaust Gas Recirculation (EGR) systems component s include and EGR Valve, and Engine Control Μodule (ECΜ) Controlled Vacuum Switch Valve or EGR Solenoid and an EGR Vacuum Μodulator. Common causes include EGR volume control solenoid valve, EGR volume control solenoid valve harness is open or shorted, EGR volume control solenoid valve circuit poor electrical connection. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.
- What it means
- P0404 Mercedes-Benz indicates Exhaust Gas Recirculation Circuit Range/Performance.
- Common causes
- Common causes include EGR volume control solenoid valve, EGR volume control solenoid valve harness is open or shorted, EGR volume control solenoid valve circuit poor electrical connection.
- Severity
- Moderate - service should be scheduled soon.
- Can I drive?
- The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.
Code P0404 Mercedes-Benz Description
The EGR system on recently built vehicles uses a step motor to control the flow rate of EGR from exhaust manifold. This motor has four winding phases. It operates according to the output pulse signal of the ECΜ. Two windings are turned ON and OFF in sequence. Each time an ON pulse is issued, the valve opens or closes, changing the flow rate. When no change in the flow rate is needed, the ECΜ does not issue the pulse signal. Α certain voltage signal is issued so that the valve remains at that particular opening.
What are the Possible Causes of the DTC P0404 Mercedes-Benz?
- EGR volume control solenoid valve
- EGR volume control solenoid valve harness is open or shorted
- EGR volume control solenoid valve circuit poor electrical connection
- EGR temperature sensor and circuit
How to Fix the DTC P0404 Mercedes-Benz?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0404 Mercedes-Benz code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
Need more information about the P0404 Mercedes-Benz code?
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Frequently Asked Questions about P0404 Mercedes-Benz Code
1. What are the common symptoms of OBDII code P0404 in a Mercedes-Benz?
- Common symptoms include rough idling, decreased fuel efficiency, engine hesitation, and the illumination of the Check Engine Light.
2. What are the possible causes of OBDII code P0404 in a Mercedes-Benz?
- Possible causes include a faulty EGR valve, clogged EGR passages, wiring issues, vacuum leaks, or a malfunctioning EGR temperature sensor.
3. How can I diagnose the OBDII code P0404 in my Mercedes-Benz?
- Diagnosis typically involves using a scan tool to retrieve the code, checking the EGR valve for proper operation, inspecting the EGR passages for blockages, and testing the EGR temperature sensor.
4. Can I drive my Mercedes-Benz with OBDII code P0404?
- It is not recommended to drive the vehicle with this code present, as it can lead to poor engine performance and potential damage if left unresolved.
5. How do I repair OBDII code P0404 in my Mercedes-Benz?
- Repairing the code may involve cleaning or replacing the EGR valve, clearing any blockages in the EGR passages, checking and repairing any wiring issues, or replacing the EGR temperature sensor if faulty.
6. Will resetting the Check Engine Light fix OBDII code P0404 in my Mercedes-Benz?
- Simply resetting the Check Engine Light will not fix the underlying issue causing the code. It is important to diagnose and address the root cause of the problem.
7. Are there any maintenance tips to prevent OBDII code P0404 in my Mercedes-Benz?
- Regularly servicing and cleaning the EGR system, using high-quality fuel, and ensuring proper engine maintenance can help prevent issues that lead to code P0404.
8. How much does it typically cost to repair OBDII code P0404 in a Mercedes-Benz?
- The cost of repairing code P0404 can vary depending on the specific cause, but it may range from a few hundred to over a thousand dollars, including parts and labor.
9. Can a DIY enthusiast fix OBDII code P0404 in a Mercedes-Benz?
- Depending on the cause of the code, some DIY enthusiasts with mechanical knowledge and the right tools may be able to address the issue themselves. However, it is recommended to consult a professional if unsure.
10. Will OBDII code P0404 cause my Mercedes-Benz to fail an emissions test?
- Yes, code P0404 is related to the exhaust gas recirculation system, which plays a role in emissions control. If the issue is not resolved, it may cause the vehicle to fail an emissions test.
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