Intake Air Heater B Circuit / Open
The controller cannot drive the secondary intake air heater (heater grid B) used on diesel engines for cold-start support. The grid stays cold so cold-start emissions and white smoke increase.
Affected components
- Intake air heater b
- Heater relay
- Wiring harness
Common causes
- High likelihood: Open heater grid element
- Medium likelihood: Failed heater relay or open coil
Diagnostic notes
- The malfunction indicator lamp may illuminate
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.