Fault code P0474 – a step-by-step guide to diagnosing and fixing it

Error code P0474 is displayed and the check engine light is on - what does this mean?

The OBD/EOBD system has detected a fault in the exhaust gas recirculation (EGR) valve control circuit, specifically an intermittent or irregular signal. This DTC P0474 indicates problems with the electrical connection or the valve itself, which means that the exhaust gas recirculation is not working properly.

What can cause this error code?

• Defective EGR valve
• Damaged wiring to the EGR valve
• Corroded or loose plug connections
• Defective EGR position sensor
• Blocked EGR lines
• Faulty engine control unit (ECU)
• Vacuum leak in the EGR system
• Defective EGR vacuum pump

What symptoms occur in parallel with fault code P0474?

• Idle problems: Unsteady or fluctuating idling of the engine
• Power loss: Reduced engine power, especially at low engine speeds
• Increased emission values: Poorer emission values during the general inspection
• Knocking noises: Metallic knocking noises from the engine compartment
• Black smoke: Dark exhaust fumes from the exhaust pipe
• Starting problems: Difficulty starting the engine, especially when the engine is cold

How to fix the problem of trouble code P0474?

• Repairing trouble code P0474 requires a systematic diagnosis of the EGR components.
• Replace the EGR valve completely and use new seals, then delete the fault memory and carry out a test drive
• Check all electrical connections to the EGR valve, replace damaged cables and clean or renew plug connections
• Replace EGR position sensor separately, carry out calibration and check system function with diagnostic device
• Clean or replace complete EGR lines, check vacuum hoses and replace if necessary
• Check engine control unit for software updates, reprogram if necessary or replace if defective
• Flush the EGR system completely, remove carbon deposits and replace all seals