Faulty fuel injector for cylinder 10, such as a sticking nozzle or internal electrical failure; Damaged or corroded wiring harness or connector at the cylinder 10 injector; Failed injection timing control solenoid or spool valve inside the high-pressure fuel pump; Contaminated or degraded engine oil affecting hydraulic injection timing components; Low fuel pressure or restricted fuel supply causing timing deviation; Faulty camshaft or crankshaft position sensor providing inaccurate timing reference; Engine control module software calibration issue or internal fault

DTC codes / P02xx · Fuel and air metering (injector circuits) / P021D

P021DCylinder 10 Injection Timing

Q: What does code P021D mean?

Cylinder 10 Injection Timing. P021D indicates that the powertrain control module has detected an out-of-range condition in the fuel injection timing circuit or control strategy for cylinder number 10. The computer compares the commanded injection timing against the expected value or feedback signal and sets this code when the deviation exceeds a calibrated threshold.

P021D indicates that the powertrain control module has detected an out-of-range condition in the fuel injection timing circuit or control strategy for cylinder number 10. The computer compares the commanded injection timing against the expected value or feedback signal and sets this code when the deviation exceeds a calibrated threshold.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaFuel and air metering (injector circuits)

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
Rough idle or misfire sensation, especially noticeable at low engine speeds
Reduced engine power or limp mode under load
Increased fuel consumption due to incorrect injection timing
Exhaust smoke or strong fuel odor from unburned fuel
Hesitation or stumble during acceleration

Common causes, most likely first

Faulty fuel injector for cylinder 10, such as a sticking nozzle or internal electrical failure
Damaged or corroded wiring harness or connector at the cylinder 10 injector
Failed injection timing control solenoid or spool valve inside the high-pressure fuel pump
Contaminated or degraded engine oil affecting hydraulic injection timing components
Low fuel pressure or restricted fuel supply causing timing deviation
Faulty camshaft or crankshaft position sensor providing inaccurate timing reference
Engine control module software calibration issue or internal fault

How to diagnose and fix it

Connect a scan tool and record all stored and pending codes, then verify the freeze-frame data for P021D
Inspect the cylinder 10 injector connector and wiring for chafing, corrosion, or loose pins
Perform a resistance and waveform test on the cylinder 10 injector circuit
Check fuel pressure and volume against the manufacturer's specification
Test the injection timing control solenoid or spool valve for proper operation
Verify camshaft and crankshaft sensor signals with an oscilloscope for timing accuracy
If all electrical and hydraulic checks pass, reprogram or replace the engine control module as a last resort

Cylinder 10 timing faults often misdiagnosed

A clogged or failing injector on cylinder 10 can set P021D without ever triggering a misfire code, so technicians who only look for misfires may miss the root cause.
Oil quality and level are critical on engines with hydraulic injection timing; degraded oil can cause timing deviation that mimics a faulty injector.
Wiring harness damage near the cylinder 10 injector is common on engines with tight routing, and a visual inspection often reveals chafed insulation.
P021D can be set by a faulty camshaft position sensor even when the engine runs smoothly, because the computer uses that signal to calculate injection timing.
Replacing the injector without checking fuel pressure or oil condition frequently leads to a repeat failure and the same code returning.

Can I keep driving with P021D?

You can drive the vehicle short distances to a repair shop, but avoid heavy acceleration, towing, or sustained high-speed driving because incorrect injection timing can damage the catalytic converter and increase fuel dilution in the oil.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.