What does it mean?
P1365 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Cylinder 4 Ignition Circuit Short to B+ .
Symptoms
- Cylinder 4 misfires or is dead, with the engine shaking at idle
- Check engine light on and often flashing under load
- Reduced power, hesitation and rough acceleration
- Fuel smell from the exhaust and increased consumption
- Symptoms that may appear or worsen after washing the engine bay if moisture is involved
Likely causes
- Control wire in contact with a powered circuit where insulation has worn through
- Moisture bridging the supply and control pins inside the coil connector
- Internal short in the coil between the feed and the primary control terminal
- Wire trapped against a live terminal or stud, often after service work in that area
- Corrosion deposits inside the plug body forming a conductive bridge
- Incorrect wiring from a previous repair or an aftermarket accessory tapped into the circuit
- Module output driver damaged by the voltage on the control line
How to fix it
- Unplug the coil and check the control wire for battery voltage with the key on; voltage where none belongs confirms the short
- Inspect the connector for moisture, corrosion and pin-to-pin contamination, then clean and dry it
- Measure between the coil supply and control terminals to detect an internal short
- Follow the harness looking for chafed sections resting against powered terminals or studs
- Check for aftermarket taps or previous repairs in the ignition circuit and correct them
- Repair the short before installing new parts so the replacement is not damaged
- Replace the coil if it is internally shorted, then confirm the control line switches normally and the misfire is gone