Fuel and air

P021D — Cylinder 10 Injection Timing Fault

Severity: medium Drive with care, to a shop

What P021D means

P021D means the engine control unit found a fault in the injection timing control for cylinder 10. It appears mainly on multi-cylinder engines, typically diesels, with direct injection, where the ECU calculates when each injector opens using crankshaft and camshaft sensor signals. If the actual timing or injector response does not match the commanded value, the check engine light comes on and the code is stored.

Symptoms

  • Check engine light on
  • Misfire, stumble or sag under load
  • Reduced power
  • Higher fuel consumption
  • Rough idle
  • Possible smoke or harsh diesel knock

Possible causes

  1. Faulty injector or injector solenoid on cylinder 10
  2. Open, shorted or corroded wiring or connector in the injector control circuit
  3. Failed or incorrect signal from the crankshaft or camshaft position sensor
  4. Worn or failed mechanical timing parts such as chain or gears
  5. Fuel pressure problems from the pump, filter or regulator
  6. Air leak causing a mixture deviation

How to diagnose

  1. Scan all codes and freeze frame data, looking for related injector or position sensor codes
  2. Review fuel trim or injector correction values and cylinder balance data on a scan tool
  3. Inspect the cylinder 10 injector harness and connector for damage, moisture and corrosion
  4. Check injector coil resistance and circuit continuity, including power and ground to the ECU
  5. Scope the crankshaft and camshaft sensor signals
  6. Measure fuel pressure and check the fuel filter condition
  7. Verify mechanical timing and look for chain stretch or gear wear
  8. Rule out intake or exhaust leaks

Common fixes

  • Replace the faulty cylinder 10 injector or solenoid and perform any required coding or adaptation
  • Repair damaged wiring and connectors
  • Replace the crankshaft or camshaft position sensor
  • Correct timing drive problems such as the chain, gears or tensioners
  • Replace the fuel filter or repair the fuel system if pressure is low

Questions and answers

What does P021D mean?

It is an injection timing fault for cylinder 10. The ECU sees that the injector is not firing as commanded, or that its control circuit has a problem.

Can I drive with P021D?

Only for a short distance, such as to a repair shop. Continued driving with misfires and wrong injection timing can damage the engine and catalytic components.

How do I fix P021D?

Start with the wiring and connector at the cylinder 10 injector, then test the injector, the crank and cam sensors and fuel pressure. The repair depends on what the tests reveal.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.