What it means
The control module detects an open in the diesel intake air flow B control circuit.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The diesel intake air flow B control circuit operates the actuator for intake air flow valve B. The control module sets this code when it detects an open circuit, meaning the electrical path is interrupted and the actuator may not respond.
Common causes
Most likely first.
- Open in actuator or wiring
- Pin pushed back out of connector body
- Cracked solder joint inside the module or sensor
Symptoms
- Check-engine light on
- Possible reduced engine power or sluggish response
How to diagnose it
- Save freeze-frame data and check live data for the commanded and reported position of intake air flow valve B to see whether the actuator responds.
- Locate valve B using vehicle service information and inspect its connector and harness for damage, loose fit, or a wire pulled out of the connector.
- Check connector terminals for a pushed-back pin or poor contact, especially at the actuator and module connectors.
- With the circuit safely powered down as specified by the manufacturer, check continuity through the control wiring and actuator circuit for an open.
- If the wiring and actuator pass, test the actuator and module connections according to the manufacturer’s diagnostic procedure before condemning either component.
Common fixes
- Reseat the connector and secure any backed-out terminal.
- Repair an open or damaged wire in the valve B control circuit.
- Repair a failed actuator or its internal connection if testing confirms the fault.
- Repair a verified internal module or sensor connection fault using the manufacturer’s procedure.
Can I keep driving?
If the engine runs normally, a short trip may be possible, but sluggish response or reduced power can make merging and passing difficult. Avoid heavy loads and high-speed driving until valve B control is restored.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.