P2371
Fuel Volume Regulator B Control Circuit Performance
The ECU sees implausible feedback on the control loop for fuel volume regulator B - duty cycle does not match measured rail pressure response. The regulator either reacts too slowly, sticks, or has shifted from its calibration.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Regulator stem sticking due to debris or wearCommon
- High-pressure pump wear changes regulator responsePossible
Parts involved
- Fuel Volume Regulator B
- High Pressure Pump B
- Fuel Rail
P2371 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.