Faulty fuel pressure solenoid (internal coil failure or sticking valve); Damaged or corroded wiring harness or connector at the solenoid; Open or short circuit in the solenoid control circuit; Failed engine control module (ECM) driver for the solenoid; Clogged fuel filter or restricted fuel line causing abnormal pressure; Loose or poor ground connection for the solenoid circuit

DTC codes / Mitsubishi codes / P1105

P1105 · MitsubishiFuel Pressure Solenoid

Q: What does code P1105 mean?

Fuel Pressure Solenoid. P1105 on Mitsubishi vehicles indicates that the engine control module (ECM) has detected an electrical fault in the fuel pressure solenoid circuit, which controls fuel pressure to the injectors. The ECM monitors the solenoid's voltage and current and sets this code when the signal falls outside the expected range, often due to an open or shorted circuit.

P1105 on Mitsubishi vehicles indicates that the engine control module (ECM) has detected an electrical fault in the fuel pressure solenoid circuit, which controls fuel pressure to the injectors. The ECM monitors the solenoid's voltage and current and sets this code when the signal falls outside the expected range, often due to an open or shorted circuit.

SystemPowertrain

Code typeMitsubishi specific

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Rough idle or stumbling, especially when the engine is cold
Hesitation or flat spots during acceleration
Poor fuel economy due to incorrect fuel pressure
Difficulty starting or extended cranking times
In rare cases, the engine may stall or enter limp mode

Common causes, most likely first

Faulty fuel pressure solenoid (internal coil failure or sticking valve)
Damaged or corroded wiring harness or connector at the solenoid
Open or short circuit in the solenoid control circuit
Failed engine control module (ECM) driver for the solenoid
Clogged fuel filter or restricted fuel line causing abnormal pressure
Loose or poor ground connection for the solenoid circuit

How to diagnose and fix it

Perform a visual inspection of the fuel pressure solenoid and its connector for damage or corrosion
Check the solenoid's resistance with a multimeter and compare to the manufacturer's specification
Test the solenoid circuit for continuity, shorts to ground, and shorts to power using a wiring diagram
Verify that the ECM is commanding the solenoid by backprobing the connector with a scope or test light
Inspect the fuel filter and lines for restrictions that could affect pressure
Replace the fuel pressure solenoid if it fails electrical or functional tests
Clear the code and perform a road test to confirm the repair

What Mitsubishi Techs Check Before Replacing the Solenoid

A stuck-open fuel pressure solenoid can cause rich running and black smoke, but often the only clue is the stored code and slightly elevated fuel trims.
The solenoid is frequently misdiagnosed as a failed ECM; always verify the control signal at the solenoid before condemning the computer.
Corrosion inside the connector pins is a common cause on older Mitsubishi models, especially in humid climates, and can mimic a failed solenoid.
A restricted fuel filter can raise pressure and cause the solenoid to work outside its expected range, setting P1105 without any solenoid fault.
On some models, the fuel pressure solenoid shares a ground with other sensors; a bad ground can set multiple codes, so check for companion codes.

Can I keep driving with P1105?

You can usually drive with P1105, but avoid aggressive acceleration and heavy loads until it is repaired, as incorrect fuel pressure may cause poor performance and increased emissions. If the engine runs rough or stalls, have it checked promptly.

Tools that help

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