What it means
The control module detected a low electrical signal in the diesel intake air flow 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 control actuator circuit carries electrical signals between the control module and the airflow valve actuator. This code sets when the module detects a signal below the expected range, which can result from a short to ground or excessive resistance at a connection.
Common causes
Most likely first.
- Short to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check-engine light on
- Reduced engine power or sluggish acceleration
- Rough idle or stalling
- Increased fuel consumption
How to diagnose it
- Save freeze-frame data and check available actuator command and position data to determine whether the low signal is constant or occurs under particular conditions.
- Inspect the intake air flow control connector and harness for corrosion, loose pins, rubbed insulation, or a wire contacting ground.
- Check connector terminals for poor contact or corrosion that could add resistance, and repair any visible damage before further tests.
- Using the manufacturer’s wiring diagram, test the signal circuit for a short to ground and check its continuity and connections.
- If the wiring checks out, test the actuator and control-module circuit as directed by the manufacturer.
Common fixes
- Clean and secure corroded or loose actuator connector terminals.
- Repair chafed wiring that is shorted to ground.
- Replace a damaged connector or terminal that has excessive contact resistance.
- Replace the actuator only if circuit testing confirms it is faulty.
Can I keep driving?
If the engine runs steadily, limit driving and avoid heavy loads because reduced airflow control can cause sluggish response or stalling. Stop if it stalls repeatedly or loses enough power to make traffic unsafe.
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.