P01D5

What it means

P01D5 is a generic powertrain code meaning the engine control unit has found that the fuel injection timing on cylinder 6 is over retarded, so injection is happening later than commanded. It sets when measured or inferred injection timing for that cylinder deviates from the target by more than the allowed amount. It is mainly seen on diesel engines with electronically controlled injection, and the exact detection method depends on the engine and fuel system.

Symptoms

• Engine misfire or rough running, especially at idle
• Loss of power and sluggish acceleration
• Excess smoke, often white or grey on a cold start
• Harsh diesel knock or uneven combustion noise
• Hard starting or extended cranking
• Malfunction indicator lamp on, possibly with reduced power mode

Possible causes

• Faulty or worn cylinder 6 injector with delayed or sluggish openinglikely
• Wiring or connector fault in the cylinder 6 injector circuit (high resistance, chafing, corrosion)likely
• Low or unstable fuel rail pressure caused by a weak pump, blocked filter or fuel supply restrictionpossible
• Crankshaft or camshaft position sensor signal fault giving incorrect timing referencepossible
• Contaminated or poor quality fuel affecting injector responsepossible
• Injector correction or calibration data not set correctly after injector or control unit replacementpossible
• Mechanical timing fault such as a slipped timing belt or chain, or a worn pump drive on engines where this appliesrare

How to diagnose

1. Read all stored and pending codes and the freeze frame data, noting engine speed, load, temperature and fuel rail pressure when the fault set
2. Check for related codes covering other cylinders, rail pressure, or crank and cam sensors, and diagnose those first
3. Visually inspect the cylinder 6 injector wiring and connector for damage, oil ingress, corrosion and poor pin tension
4. Inspect the fuel filter, fuel level and fuel quality, and check for air in the fuel or supply restrictions
5. Review live data for fuel rail pressure against target and for injector correction values or cylinder balance figures
6. Check the crank and cam sensor signals and their wiring against specification for your model
7. Test the injector circuit resistance and operation using the manufacturer's procedure, then compare cylinder 6 with the others
8. Where the engine allows, check mechanical timing and injector condition using the manufacturer's data

How to fix

• Repair or replace damaged wiring or connectors in the cylinder 6 injector circuit
• Replace the cylinder 6 injector if it is confirmed faulty, and code or adapt it to the control unit as the manufacturer requires
• Replace the fuel filter and correct any supply or pressure problems found in the low or high pressure fuel system
• Replace a faulty crank or cam sensor, or repair its wiring
• Drain and replace contaminated fuel, then bleed the system as required
• Correct the mechanical timing if it is found to be out, following the manufacturer's procedure

Can I keep driving?

Nearby codes

• P01D4GenericCylinder 5 Injection Timing Performance - Over Advanced
• P01D6GenericCylinder 6 Injection Timing Performance - Over Advanced