Faulty cylinder 5 fuel injector with internal coil short; Damaged, chafed or shorted injector wiring between the injector and the control module; Corroded, loose or damaged injector connector or harness connector terminals; Water or fuel contamination in the injector connector or harness; Faulty injector driver inside the powertrain control module; Outdated control module calibration, only where the manufacturer has issued a known update for this code on that engine.

P1265

Cylinder 5 High To Low Side Short.

Lincoln
Powertrain
Manufacturer code
Medium severity

How this code is built

P: SystemPowertrain
1: Defined byThe manufacturer
2: AreaFuel and air metering (injector circuit)
65: FaultThe specific fault in that area

What it means

P1265 on a Lincoln means the powertrain control module has detected a short between the high side and low side of the cylinder 5 fuel injector circuit. The module monitors the injector driver and its feed and return wiring, and it set the code because the electrical readings for that injector were outside the expected range. The exact driver arrangement and circuit layout depend on the model and engine, so check the wiring information for the specific vehicle.

Symptoms

Engine misfire, often felt as a rough or uneven idle
Hesitation or loss of power under acceleration
Malfunction indicator lamp lit
Poor fuel economy
Difficult starting or a cylinder that appears dead
Fuel smell from the exhaust if the injector is stuck open

Possible causes

Faulty cylinder 5 fuel injector with internal coil shortlikely
Damaged, chafed or shorted injector wiring between the injector and the control modulelikely
Corroded, loose or damaged injector connector or harness connector terminalspossible
Water or fuel contamination in the injector connector or harnesspossible
Faulty injector driver inside the powertrain control modulerare
Outdated control module calibration, only where the manufacturer has issued a known update for this code on that enginerare

How to diagnose

Read the stored and pending codes and note the freeze frame data, then check for any other injector or misfire codes
Visually inspect the cylinder 5 injector connector and surrounding harness for chafing, heat damage, corrosion and looseness
Check the harness routing near the engine, brackets and sharp edges where the wiring could rub through
Measure the cylinder 5 injector coil resistance and compare it with the specification for the engine
Compare the cylinder 5 injector resistance with the other cylinders to spot an obvious difference
With the connector disconnected, test the injector wiring for shorts to ground, to power and between the two circuits using the wiring diagram
Check the injector operation with the engine running, for example by listening for a regular click or by using a suitable injector test, and confirm the driver signal is present
Check whether any manufacturer service information or calibration update applies to this code on the specific model and engine

How to fix

Replace the cylinder 5 fuel injector if its resistance or operation is faulty, following the correct procedure for the engine
Repair or replace any damaged injector wiring and secure the harness away from heat and sharp edges
Clean or replace corroded or damaged connectors and terminals, and ensure they are fully seated
Dry out and repair the source of any water or fuel ingress into the connector
Replace or repair the powertrain control module only after the injector and wiring have been proven good
Apply an official calibration update only if service information confirms it addresses this fault

Can I keep driving?

Medium severity

The car can be driven a short distance if it runs acceptably, but get it fixed soon. A misfiring or leaking injector can wash oil from the cylinder wall and overload the catalytic converter, so avoid heavy loads and stop if the misfire is severe or the lamp flashes.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.