EGR Cooler B Efficiency Below Threshold
The temperature drop across EGR cooler B is below the calibrated threshold - cooler is fouled with soot, has internal scaling, or coolant flow is restricted. Recirculated gas reaches the intake hotter than designed, increasing NOx and combustion temperatures.
Affected components
- Egr cooler b
Common causes
- High likelihood: Cooler fouled with soot or scaled
Possible symptoms
- Check engine light on
- Pinging or knocking under load
- Power loss and hesitation
- Possible rough idle
- Failed emissions inspection (NOx)
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.