Severity High
P021F

Cylinder 12 Injection Timing Malfunction

📅 Last reviewed: July 2026
What does the P021F code mean?

The P021F code indicates that the engine control module (ECM) has detected an incorrect injection timing for cylinder 12. This typically occurs when the fuel injector's timing deviates from the expected value, often due to a faulty injector, wiring issues, or problems with the camshaft or crankshaft position sensors. The ECM monitors the timing of each injector pulse and compares it to the desired timing; if the deviation exceeds a threshold, the code is set. This can lead to reduced engine performance, increased emissions, and potential engine damage if not addressed.

High
Severity
$50-$150
Typical Cost
High
Frequency

1. Most Common Causes

2. Symptoms You Will Notice

3. Step-by-Step Diagnosis

1

Step 1: Scan for additional codes and freeze frame data to confirm P021F.

2

Step 2: Visually inspect wiring and connectors for injector 12 for damage or corrosion.

3

Step 3: Test injector 12 resistance and compare to specifications; replace if out of range.

4

Step 4: Check camshaft and crankshaft position sensor signals with a scope or scan tool.

5

Step 5: If all else fails, update or reprogram the ECM per manufacturer instructions.

4. Frequently Asked Questions

Is it safe to drive with this code?

It is not recommended to drive long distances as it can cause engine damage and poor performance. Immediate diagnosis is advised.

How much does it cost to fix?

The cost typically ranges from $50 to $150 for diagnosis and repair, but may be higher if injector replacement is needed.

5. Commonly Affected Makes

This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.

6. Related Codes

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