Cylinder 4 Injector Circuit Range/Performance
The P02F1 code indicates that the Engine Control Module (ECM) has detected an issue with the electrical circuit or performance of the fuel injector on cylinder 4. This could be due to a faulty injector, wiring problems, or a malfunctioning ECM. The injector circuit is monitored for proper voltage and current; if the readings fall outside the expected range, this code is set.
1. Most Common Causes
- Faulty fuel injector on cylinder 4 or injector resistance out of specification
- Corroded, loose, or damaged electrical connections in the injector circuit
- Short to ground, short to voltage, or open circuit in the injector wiring harness
- Excessive circuit resistance due to deteriorated splices, terminals, or connectors
- Internal ECM/PCM failure (less common but possible)
- Mechanical injector issues such as partial clogging or worn internal coil
2. Symptoms You Will Notice
- Engine misfire on cylinder 4
- Rough idle or hesitation
- Check Engine Light illuminated
- Decreased fuel economy
3. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm the code and check for other codes.
Step 2: Visually inspect the injector wiring and connector for damage or corrosion.
Step 3: Measure resistance of cylinder 4 injector and compare to specifications (typically 12-16 ohms).
Step 4: Perform a injector balance test or use a noid light to check for injector pulse.
Step 5: If wiring and injector are good, test the ECM output for cylinder 4.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can cause catalytic converter damage due to unburned fuel. Short trips to a repair shop are acceptable.
How much does it cost to fix?▼
The cost typically ranges from $150 to $400, including parts and labor, depending on the cause and vehicle make.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.