Injector Circuit Malfunction - Cylinder 1
The PCM detected a circuit malfunction in the fuel injector for cylinder 1, meaning the injector is not responding correctly to the engine control module's commands. This prevents proper fuel delivery to cylinder 1, causing combustion problems and engine performance issues.
What You Might Notice
- Engine misfire on cylinder 1
- Rough, hesitant idle
- Poor acceleration and reduced power
- Check engine light (MIL) illuminated
- Possible fuel smell or black smoke from exhaust
Most Common Causes
- 1
Faulty fuel injector
The injector is stuck open, stuck closed, or electrically unresponsive. This is the most common cause of P0201.
- 2
Open or broken wiring to injector
Damaged, disconnected, or corroded wiring between the PCM and the cylinder 1 fuel injector breaks the circuit.
- 3
Short circuit in injector wiring
A short to ground or power in the injector circuit causes the PCM to lose proper control of the injector.
- 4
Faulty PCM or injector driver
The engine control module or its injector driver circuit has failed, preventing proper signal output to the cylinder 1 injector.
How to Diagnose It
- 1
Check Faulty fuel injector — The injector is stuck open, stuck closed, or electrically unresponsive. This is the most common cause of P0201.
- 2
Check Open or broken wiring to injector — Damaged, disconnected, or corroded wiring between the PCM and the cylinder 1 fuel injector breaks the circuit.
- 3
Check Short circuit in injector wiring — A short to ground or power in the injector circuit causes the PCM to lose proper control of the injector.
- 4
Check Faulty PCM or injector driver — The engine control module or its injector driver circuit has failed, preventing proper signal output to the cylinder 1 injector.
How to Fix It
- 1
Replace cylinder 1 fuel injector
Remove and replace the faulty injector with a new OEM or quality replacement. Disconnect the fuel rail, remove the injector connector, unscrew the injector, and install the new unit with a fresh O-ring.
- 2
Inspect and repair injector wiring
Check the wiring harness and connector leading to the cylinder 1 injector for corrosion, breaks, or damage. Repair or replace damaged wiring and clean corroded connectors.
- 3
Test injector electrical resistance
Use a multimeter to measure the resistance of the injector coil. If out of specification (typically 10-14 ohms), the injector is faulty and requires replacement.
- 4
Replace PCM if diagnosis confirms
If wiring and injector test good, the engine control module or injector driver circuit has failed. This requires PCM replacement and reprogramming.
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