What it means
The control module detects a high electrical condition 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 carries the electrical command for valve B’s actuator. This code sets when the module detects voltage higher than expected in that circuit, which can indicate a short to a power supply or a poor connection affecting the signal.
Common causes
Most likely first.
- Control line shorted to supply
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check-engine light on
- Possible reduced engine power or sluggish response
How to diagnose it
- Save freeze-frame data and check live commanded and actual positions for valve B to see whether it responds to control commands.
- Inspect the control harness for pinching or damaged insulation where it could contact a battery-positive or other supply wire.
- Check valve B and module connectors for corrosion, loose pins, or terminals that could disrupt the circuit.
- With the circuit isolated as directed by the manufacturer, test the control line for a short to supply and inspect its continuity.
- If the wiring passes, check the actuator and module circuit against the manufacturer’s specification before replacing parts.
Common fixes
- Repair wiring shorted to a power supply in the valve B control circuit.
- Correct pinched or damaged harness routing and insulation.
- Clean or repair corroded, loose, or damaged connector terminals.
- Replace a confirmed faulty actuator or repair a verified module-side fault.
Can I keep driving?
Reduced power or sluggish response may make merging and passing unsafe. Keep speed and engine load modest, and stop if the engine’s response becomes unpredictable.
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.