TorqueMech OBD Code Guide
P0402 - Exhaust Gas Recirculation Flow Excessive Detected
EGR flow is higher than expected.
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Code Overview
EGR flow is higher than expected.
Common Causes
- EGR valve stuck open
- Control solenoid holding the valve on
- Carbon preventing the EGR valve from seating
- Feedback sensor reporting flow incorrectly
Symptoms
- Rough idle or stalling
- Stumble off idle
- Check-engine light with reduced combustion stability
Diagnostic Steps
- Inspect the EGR valve for sticking or carbon buildup
- Check whether the valve is being commanded open when it should be closed
- Inspect vacuum or electronic control components for constant EGR command
- Compare EGR feedback data to actual engine behavior if equipped
Repair Difficulty
Moderate
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