P2370
Fuel Volume Regulator B Control Circuit Open
An open circuit is detected on the control line for the second fuel volume regulator (B) used on twin high-pressure-pump diesel systems. Without this regulator the high-pressure pump cannot meter fuel for its assigned cylinder bank, leading to rail-pressure faults and limp-home behaviour.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Open in harness or connector to regulator BCommon
- Regulator solenoid winding openPossible
- Pin pushed back out of connector bodyLess likely
Parts involved
- Fuel Volume Regulator B
- High Pressure Pump B
- Fuel Rail
P2370 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.