Faulty or sticking fuel injector on cylinder 10; Wiring damage, chafing or poor connector contact in the cylinder 10 injector circuit; Low or unstable fuel pressure or poor fuel quality affecting injection; Crankshaft or camshaft position sensor signal fault causing timing errors; Injector driver fault or internal fault in the engine control unit; Mechanical timing problem such as a stretched chain or belt or a jumped tooth.

P021D

Cylinder 10 Injection Timing.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
2: AreaFuel and air metering (injector circuit)
1D: FaultThe specific fault in that area

What it means

P021D is a generic powertrain code meaning the engine control unit has detected a problem with the injection timing on cylinder 10. The ECU compares commanded injection timing with what it can measure or infer, and has seen a fault or a deviation outside the allowed range. It only applies to engines with ten or more cylinders, and the exact monitoring method depends on the engine.

Symptoms

Malfunction indicator lamp on
Rough running or misfire, especially at idle
Loss of power or reduced performance
Hard starting or extended cranking
Increased fuel consumption
Engine in limp mode or reduced power

Possible causes

Faulty or sticking fuel injector on cylinder 10likely
Wiring damage, chafing or poor connector contact in the cylinder 10 injector circuitlikely
Low or unstable fuel pressure or poor fuel quality affecting injectionpossible
Crankshaft or camshaft position sensor signal fault causing timing errorspossible
Injector driver fault or internal fault in the engine control unitrare
Mechanical timing problem such as a stretched chain or belt or a jumped toothrare

How to diagnose

Read all stored and pending codes and note any related injector, misfire, fuel pressure or sensor codes
Review freeze frame data for engine speed, load, temperature and fuel pressure when the fault set
Inspect the wiring and connectors to the cylinder 10 injector for damage, corrosion, chafing or heat damage
Check for misfire counts on cylinder 10 and compare with other cylinders
Check live fuel pressure against specification and look at fuel quality and filter condition where applicable
Check crankshaft and camshaft sensor signals and their wiring for correct readings
Test the cylinder 10 injector electrical resistance and operation against the manufacturer data, as the method depends on injector type
Check for software updates or known issues for the specific model and engine, and verify mechanical timing if signals point that way

How to fix

Repair or replace damaged wiring or connectors in the injector circuit
Replace the cylinder 10 injector if it is confirmed faulty, and code or adapt it if the engine requires this
Correct fuel supply faults such as a weak pump, blocked filter or regulator problem, and replace contaminated fuel
Replace a faulty crankshaft or camshaft position sensor
Correct mechanical timing faults found during inspection
Update the ECU calibration only if an outdated calibration is a known cause for that model, or repair or replace the ECU if it is confirmed faulty

Can I keep driving?

Medium severity

Short, gentle trips to a workshop are usually acceptable, but fix it soon as ongoing misfire or incorrect injection can damage the catalytic converter or engine. Stop driving if the engine runs very roughly, the MIL flashes or power is badly reduced.

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