P016F: Closed Loop Fuel Pressure Control At Limit - Pressure Too Low

What does P016F mean?

Common-rail diesels regulate rail pressure in closed loop: the control module compares the rail pressure sensor with the target and adjusts a volume or pressure control valve, learning correction factors as it goes. CARB requires faults to be flagged when this feedback control does not start in time or runs out of authority. P016F means the controller is at its limit in the 'more pressure' direction and the actual pressure still stays below target. Which circuit is meant depends on the manufacturer: Volvo and Mack use it for rail pressure, for example as a follow-up when their electronic pressure relief valve stays open (P009B); on FCA's 3.0 EcoDiesel it concerns the regulated low-pressure supply via the fuel pump control module and appears with P025C and P01C6, partly fixed by new engine software. No public thresholds exist. Weak supply pumps, clogged filters and corroded connectors or grounds are typical causes.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine light on
• Loss of power, sluggish acceleration
• Hard starting, long cranking, stalling after start
• Rough cold idle

Common causes

• High Weak low-pressure supply: lift/tank pump, pump control module, clogged filter
• High Connector or ground problems (corrosion, water) at pump module, low-pressure sensor or ground point
• Medium Pressure relief valve open or its control circuit interrupted
• Medium Worn high-pressure pump or internal leak
• Low Engine control module software

Likelihood is a general estimate across vehicles; your make and model may differ.