P016D

What it means

P016D is the generic code for the fuel pressure control system taking too long to enter closed loop operation. After start-up the engine control unit expects actual fuel rail pressure to settle close to the target so it can switch from open loop to closed loop regulation within a set time. It saw that the pressure did not reach or hold the target range in time, so it logged the fault.

Symptoms

• Extended cranking or hesitant starting
• Rough or unstable idle after start-up
• Hesitation or poor throttle response when pulling away
• Reduced power or the engine running in a limited mode
• Engine warning light on
• Higher than usual fuel consumption

Possible causes

• Weak or failing fuel pump, or a low pressure supply issue such as a blocked fuel filter or inlet strainerlikely
• Faulty fuel rail pressure sensor giving a slow, biased or erratic signallikely
• Fuel pressure regulator or pressure control valve sticking or not responding as commandedlikely
• Wiring or connector fault (high resistance, corrosion, poor earth) in the pump, sensor or regulator circuitspossible
• Fuel leak or internal injector leak causing pressure to bleed downpossible
• Poor fuel quality, contaminated fuel or low fuel levelpossible
• Faulty or outdated engine control unit calibration, where the manufacturer has issued an update for this faultrare

How to diagnose

1. Read all stored codes and freeze frame data, noting engine temperature, fuel rail pressure and load when the fault set, and check for related fuel pressure or pump codes
2. Check the fuel level and look for service history of fuel filter changes or recent fuel contamination
3. Visually inspect wiring, connectors and earths for the fuel pump, rail pressure sensor and pressure regulator for damage, corrosion or looseness
4. Inspect the fuel system for external leaks and smell for fuel around the rail, lines and injectors
5. Compare commanded and actual fuel rail pressure on live data during start-up, idle and a light load, and see whether it lags or never reaches target
6. Check low pressure supply pressure and volume against the manufacturer's specification, as the method and values depend on the model and engine
7. Test the rail pressure sensor signal and the regulator or control valve operation with the key on and while running, following the manufacturer's procedure
8. Check for a leak-down or injector return problem if pressure falls quickly after shutdown, using the procedure for that engine

How to fix

• Replace a failing fuel pump or blocked fuel filter or strainer as confirmed by pressure and volume tests
• Replace a faulty fuel rail pressure sensor
• Replace or clean a sticking pressure regulator or control valve where the manufacturer allows, and replace if it is faulty
• Repair damaged wiring, connectors or earths in the affected circuits
• Repair fuel leaks or replace leaking injectors, then drain and replace contaminated fuel if necessary
• Apply a manufacturer calibration update only if a known issue is documented for that vehicle

Can I keep driving?

Nearby codes

• P016CGenericClosed Loop Air/Fuel Ratio Control At Limit - System Too Lean
• P016EGenericClosed Loop Fuel Pressure Control At Limit - Pressure Too High