Faulty or sticking fuel injector on cylinder 9 delaying or restricting fuel delivery; Wiring or connector fault in the cylinder 9 injector circuit (high resistance, corrosion, chafing); Low or unstable fuel pressure from a weak pump, blocked filter or failing pressure regulation; Crankshaft or camshaft position sensor signal fault or timing correlation problem affecting injection timing; Fuel contamination or poor quality fuel affecting injector response; Mechanical timing fault such as a stretched chain or belt, or a worn pump drive, depending on engine design; Engine control unit fault or outdated calibration known for this issue on the specific engine.

P01DB

Cylinder 9 Injection Timing Performance - Over Retarded.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
1: AreaFuel and air metering
DB: FaultThe specific fault in that area

What it means

P01DB is a generic powertrain code meaning the injection timing for cylinder 9 is over-retarded, so fuel is being delivered later than the engine control unit has commanded. The control unit compares actual or measured injection timing against the target and sets the code when the difference goes beyond its limit. It only applies to engines with at least nine cylinders, and the exact way timing is monitored depends on the engine and fuel system.

Symptoms

Rough running or a noticeable misfire on one cylinder
Loss of power or sluggish acceleration
Increased exhaust smoke or a strong fuel smell
Hard starting or extended cranking
Higher fuel consumption
Engine warning light on, possibly with the engine in limp mode

Possible causes

Faulty or sticking fuel injector on cylinder 9 delaying or restricting fuel deliverylikely
Wiring or connector fault in the cylinder 9 injector circuit (high resistance, corrosion, chafing)likely
Low or unstable fuel pressure from a weak pump, blocked filter or failing pressure regulationpossible
Crankshaft or camshaft position sensor signal fault or timing correlation problem affecting injection timingpossible
Fuel contamination or poor quality fuel affecting injector responsepossible
Mechanical timing fault such as a stretched chain or belt, or a worn pump drive, depending on engine designrare
Engine control unit fault or outdated calibration known for this issue on the specific enginerare

How to diagnose

Read all stored and pending codes and record freeze frame data, noting engine load, speed and temperature when the fault set
Check for other related codes such as misfire, fuel pressure, or crank/cam correlation faults and deal with those first
Inspect the cylinder 9 injector wiring and connector for damage, corrosion, loose pins or oil contamination
Check the fuel level and quality, and inspect the fuel filter condition where it is serviceable
Check live data for fuel pressure against the target and look at injector correction or balance values for cylinder 9 compared with the other cylinders
Test the injector circuit and injector electrical resistance against the manufacturer specification, and check the drive signal
Check crankshaft and camshaft sensor signals and the mechanical timing condition against the manufacturer procedure
Check for any applicable software updates or technical bulletins for the engine concerned

How to fix

Repair or replace damaged wiring, terminals or connectors in the cylinder 9 injector circuit
Replace the cylinder 9 injector if it fails electrical or flow and balance tests, following the manufacturer coding or adaptation procedure
Restore correct fuel pressure by replacing a faulty pump, filter or pressure control component
Replace faulty crankshaft or camshaft position sensors, or correct mechanical timing faults
Drain and replace contaminated fuel and renew the filter
Update the engine control unit calibration only where an outdated or faulty calibration is a confirmed cause

Can I keep driving?

Medium severity

The car can usually be driven short distances to a workshop, but avoid heavy loads and high revs. If it runs very roughly, flashes the warning light, or smokes heavily, stop driving, as unburnt fuel can damage the engine and catalytic converter.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.