Faulty fuel injector for cylinder 4 (internal coil or mechanical issue); Damaged or corroded electrical connector at the injector; Chafed, broken, or shorted wiring in the injector harness; PCM driver circuit fault for that injector channel; Low fuel pressure or contaminated fuel affecting injector performance; Loose or poor engine ground affecting injector operation

DTC codes / P02xx · Fuel and air metering (injector circuits) / P02F1

P02F1Cylinder 4 Injector Circuit Range/Performance

Q: What does code P02F1 mean?

Cylinder 4 Injector Circuit Range/Performance. P02F1 indicates that the powertrain control module (PCM) has detected an abnormal condition in the electrical circuit for the fuel injector serving cylinder 4, specifically a range or performance fault rather than a simple open or short. The PCM monitors injector current and response time, and when the signal falls outside the expected window for a calibrated period, it stores this code and may disable the injector to protect the engine.

P02F1 indicates that the powertrain control module (PCM) has detected an abnormal condition in the electrical circuit for the fuel injector serving cylinder 4, specifically a range or performance fault rather than a simple open or short. The PCM monitors injector current and response time, and when the signal falls outside the expected window for a calibrated period, it stores this code and may disable the injector to protect the engine.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering (injector circuits)

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
Rough idle or misfire felt as a shake or stumble, especially when cold
Noticeable loss of power and reduced fuel economy
Engine may enter limp mode or flash the check engine light under load
Increased hydrocarbon emissions and a raw fuel smell from the exhaust
In some cases, the engine may stall or hesitate during acceleration

Common causes, most likely first

Faulty fuel injector for cylinder 4 (internal coil or mechanical issue)
Damaged or corroded electrical connector at the injector
Chafed, broken, or shorted wiring in the injector harness
PCM driver circuit fault for that injector channel
Low fuel pressure or contaminated fuel affecting injector performance
Loose or poor engine ground affecting injector operation

How to diagnose and fix it

Perform a visual inspection of the cylinder 4 injector connector and wiring for damage or corrosion
Use a noid light or oscilloscope to check for a proper injector pulse signal at the connector
Measure injector resistance with a multimeter and compare to manufacturer specifications
Check fuel pressure and inspect fuel for contamination or restricted flow
Swap the cylinder 4 injector with a known-good injector from another cylinder to see if the code moves
Inspect and test the injector driver circuit from the PCM to the injector for continuity and shorts
If all electrical and fuel checks pass, replace the cylinder 4 fuel injector and clear the code

Before you replace the cylinder 4 injector

A loose or corroded connector pin at the injector is a frequent cause that mimics a failed injector and costs nothing to fix.
The code can be set by a mechanical injector problem such as a clogged nozzle or internal leak, not just an electrical fault.
Swapping the injector to another cylinder is the quickest way to confirm whether the fault follows the injector or stays with the circuit.
A weak battery or poor engine ground can cause injector performance codes on multiple cylinders, so check charging system health first.
Some vehicles require a relearn or adaptation reset after injector replacement to avoid a repeat code.

Can I keep driving with P02F1?

It is generally safe to drive short distances to a repair shop, but avoid heavy acceleration or towing because a misfiring cylinder can overheat the catalytic converter. If the check engine light flashes or the engine runs very rough, stop driving and arrange a tow.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.