P2371Fuel Volume Regulator B Control Circuit Performance
- 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
- P2371 is a functional fault of the second fuel volume regulator: the control circuit works electrically, but the valve does not achieve what the ECM asks of it. No manufacturer publishes a definition for regulator B, so the A side helps. Deutz's EMR controller, for example, compares the regulator current with its set point and records separate faults when it stays above or below it, plus a plausibility check of the current. Ford's 2023 diesel uses its P0002 for a different case – the driver stage in the ECM getting hotter than 170 °C. CARB also requires a fault when fuel pressure control reaches its limits and the commanded pressure can no longer be delivered. A sticking valve, dirt in the fuel or a worn pump are the usual causes.
- What you may notice
- Check engine light on
- Rail pressure fluctuates or misses its target
- Reduced power under load
- Likely causes
- LikelyRegulator B valve sticking from dirt or wear
- PossibleHigh-pressure pump B worn
- RareECM driver stage overheating
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €3,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.