Cylinder 12 Injection Timing Malfunction
The P021F code indicates that the Engine Control Module (ECM) has detected an incorrect injection timing for cylinder 12. This can be caused by a faulty fuel injector, issues with the camshaft or crankshaft position sensors, or problems with the timing chain/belt. The ECM monitors the timing of fuel injection relative to the engine's position; if the timing is off, it can lead to poor combustion, reduced power, and increased emissions.
01. Most Common Causes
- Faulty fuel injector on cylinder 12
- Malfunctioning camshaft or crankshaft position sensor
- Timing chain/belt stretched or skipped a tooth
- ECM software or hardware issue
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine misfire or rough idle
- Reduced engine power and acceleration
- Poor fuel economy
03. Step-by-Step Diagnosis
Step 1: Scan for additional codes and freeze frame data to confirm P021F.
Step 2: Inspect wiring and connectors to cylinder 12 injector and position sensors.
Step 3: Test fuel injector resistance and operation using a multimeter or injector tester.
Step 4: Check camshaft and crankshaft sensor signals with an oscilloscope.
Step 5: Verify timing chain/belt alignment and tension.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as incorrect injection timing can cause engine damage and poor performance.
How much does it cost to fix?▼
Repair costs vary from $200 to $800 depending on the root cause, such as injector replacement or timing chain repair.