P0201 P0xxx · Powertrain (P) High severity
Injector Circuit Malfunction — Cylinder 1
The ECU detects an electrical problem on the cylinder 1 injector driver circuit: open, short, or a coil that is out of specification.
Severity guidance: High — stop driving and diagnose now; risk of further damage
Symptoms you will notice
- Hard misfire on cylinder 1
- Fuel smell from the exhaust
- Rough running
- Possible catalyst damage from raw fuel
Common causes
Ordered from most to least likely — start at the top.
- 1 Failed injector coil
- 2 Open or shorted injector wiring
- 3 Corroded injector connector
- 4 Failed ECU driver (rare)
How to diagnose it
Cheapest and least invasive first — most of these codes are not a parts problem.
- ✓ Confirm the misfire follows the cylinder with a misfire counter, not just a feel.
- ✓ Measure injector resistance at the connector and compare with specification.
- ✓ Swap the injector with another cylinder; if the fault moves, the injector is bad.
- ✓ Use a noid light or scope the injector pulse to check the ECU is driving it.
Repair options
- Replace the faulty injector
- Repair the wiring or connector
- ECU repair if the driver stage is dead
P0201 — frequently asked questions
Can I drive with a dead injector? +
No — raw fuel washes the cylinder and destroys the catalytic converter within a short distance.
Should I replace all injectors? +
If mileage is high, replacing the full set avoids doing the labour twice; at minimum have the whole set flow-tested and cleaned.
Confirm the diagnosis before you buy parts
Send us the code, freeze-frame data and the vehicle — our engineers will tell you what to test first.