P0407 - Exhaust Gas Recirculation Sensor 'B' Circuit Low
P0407 Possible Causes
- Faulty EGR volume control solenoid valve
- Carbon built up on EGR valve
- EGR volume control solenoid valve harness is open or shorted
- EGR volume control solenoid valve circuit poor electrical connection
- Faulty EGR temperature sensor and circuit
How do I fix code P0407?Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.
Cost of diagnosing the P0407 code
Labor: 1.0The cost of diagnosing the P0407 code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle's make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
When is the code detected?An improper voltage signal is sent to ECM through the valve
- Engine Light ON (or Service Engine Soon Warning Light)
- Engine hesitation
P0407 DescriptionEarly 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. Depending on the engine and driving conditions, the ECΜ will control the EGR Solenoid which will operate the EGR Vacuum Μodulator to regulate the opening and closing of the EGR Valve.
The EGR system on recently built vehicles uses a step motor to control the flow rate of EGR from the 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.
More InformationNeed more information on how to fix the P0407 code?
Get Access to Factory Service Manuals
Information for specific makes
- P0407 MERCEDES-BENZ Exhaust Gas Recirculation Sensor 'B' Circuit Low
Need more help?Get the P0407 code diagnosed by a professional: Find a repair shop in your area
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