P2392Diesel Intake Air Flow B Control Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2392 is set when the module finds the motor output for the B intake throttle pulled towards ground, for example by a chafed wire touching the engine, water inside the connector or a shorted motor. The output stage protects itself and switches off. No manufacturer documents P2392 publicly. Ford's 2023 diesel summary checks the matching A-valve fault (P02E2) continuously while the power stage is active and needs only 0.2 s to register it. Because an H-bridge drives the motor, a ground short on either motor lead can be the trigger; whether the code points to one particular lead depends on the maker. With the motor dead the flap returns to its spring position, open on most designs: driveability changes little, but the EGR rate drops and the module may refuse to regenerate the particulate filter.
- What you may notice
- MIL on, code returns immediately after clearing
- Regeneration blocked or aborted
- Little or no change in driving
- Likely causes
- LikelyMotor lead chafed through and touching engine or body ground
- PossibleWater or corrosion in the throttle connector
- PossibleInternal short of the throttle motor to its housing
- RareDamaged H-bridge in the engine control module
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €40 – €500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.