Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that there's a problem with the electrical connection to the fuel injector for cylinder 2 in your car's engine. It's like a broken wire that stops the injector from working properly.
The engine control module (ECM) has detected an open circuit in the low side of the high-pressure injector for cylinder 2.
The P3104 code indicates that the ECM has found an open circuit in the low side of the high-pressure injector for cylinder 2. This means that the electrical path is interrupted, preventing the injector from receiving the necessary signals to operate correctly.
• Engine misfire
• Poor fuel economy
• Check engine light on
• Faulty injector
• Damaged wiring or connectors
• Faulty ECM
ECM: Engine Control Module, the computer that controls engine functions.
Injector: A device that sprays fuel into the engine's cylinders.
• Inspect the injector wiring and connectors for damage.
• Check the resistance of the injector.
• Test the ECM for faults.
• Repair or replace damaged wiring or connectors.
• Replace the faulty injector.
• Replace or reprogram the ECM if necessary.
• Multimeter
• OBD-II scanner
• Basic hand tools
$200 - $600
Moderate
• Toyota Prius
• Lexus CT 200h
• Honda Insight
• Regular maintenance checks
• Ensure proper electrical connections
• Avoid harsh driving conditions
Engine Performance
• Get the vehicle inspected by a professional.
• Avoid driving the vehicle until repaired to prevent further damage.
Check with the vehicle manufacturer for warranty coverage on fuel system components.
This code has been associated with issues in hybrid vehicles where high-pressure fuel systems are used.
Moderate – Should be addressed soon to avoid engine performance issues.
Driving with a malfunctioning injector can lead to increased emissions and potential engine damage.
• Engine running
• Fuel system pressurized
The fuel injector for cylinder 2 is located on the engine's intake manifold, near the corresponding cylinder.
Q: Can I drive with a P3104 code?
A: It's not recommended to drive with this code as it can cause engine performance issues and increased emissions.
Q: How do I know if my injector is faulty?
A: Symptoms of a faulty injector include engine misfires, poor fuel economy, and a check engine light.
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Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
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Universal · Wire connectors and repair kit
Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
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Fitment Required · Vehicle-fitment part
Commonly relevant for misfire, ignition-efficiency, and some drivability-related repairs.
Misfire and ignition-related faults commonly involve spark plugs as part of the repair path.
Check the correct plug type, gap, and engine application for your vehicle.
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Fitment Required · Vehicle-fitment part
Relevant when the fault points toward ignition-coil performance or cylinder-specific ignition issues.
Some ignition faults involve coil performance or cylinder-specific coil problems.
Match the coil to your engine and confirm the failed component before ordering.
View options on AmazonThese parts may be related to this fault category, but a code by itself does not confirm exact fitment or guarantee that replacing a part will solve the problem.