P02F1
Cylinder 4 Injector Circuit Range/Performance
Fuel injector circuit
Generic OBD-II
High
What it means
P02F1 means the ECM sees the cylinder 4 fuel injector's electrical signal drifting outside its expected range. That usually points to a failing injector or a wiring/connection problem on that cylinder, which can make cylinder 4 misfire and run rough until it is repaired.
High
Can I keep driving? You can usually drive, but cylinder 4 may misfire and run rough — fix it promptly to avoid unburned fuel damaging the catalytic converter.
Common symptoms
What you'll notice
- Check-engine light on
- Rough running or a misfire from cylinder 4
- Hesitation or reduced power under load
- Occasional rough idle
Common causes
Most likely first
- Failed fuel injector on cylinder 4Likely
- Open, shorted, or chafed wiring to the cylinder 4 injectorCommon
- Poor or corroded connection at the injector connectorCommon
- Injector driver fault in the ECM or injector control module (less common)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and confirm the fault is on cylinder 4.
- Inspect the injector connector and wiring for damage, corrosion, or a loose pin.
- Measure the injector's resistance and compare it to the other injectors.
- Check injector control/driver supply and ground circuits at the module.
- Replace the cylinder 4 injector if it is out of spec; clear and re-test.
FAQ
Quick answers
Is it safe to drive with P02F1?+
Short trips are usually fine, but a misfiring cylinder dumps raw fuel into the exhaust and can overheat the catalytic converter, so repair it soon.
Can I just clear P02F1?+
It will come back until the injector or its circuit is fixed. Clearing only resets the light temporarily.
Related codes
Often seen with P02F1
Read & clear P02F1 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX