P0403 - Exhaust Gas Recirculation Circuit Malfunction
EGR control circuit fault detected.
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Code Overview
EGR control circuit fault detected.
Common Causes
- Wiring or connector fault in the EGR control circuit
- Failed EGR solenoid or actuator
- Poor power or ground supply to the EGR valve
- ECM driver fault in rare cases
Symptoms
- Check-engine light with possible rough idle
- EGR function may not respond when commanded
- Failed emissions test or part-throttle drivability complaints
Diagnostic Steps
- Inspect the EGR wiring and connectors for damage or corrosion
- Check power, ground, and control signals at the EGR valve or solenoid
- Measure solenoid or actuator resistance if service information supports it
- Confirm the circuit fault before replacing the valve or control module
Repair Difficulty
Moderate
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