Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
The car's computer is having trouble controlling the fuel injector for cylinder number 4. It's like trying to turn on a light, but the switch isn't working right.
The engine control module (ECM) is detecting a low voltage condition in the high side circuit of the high-pressure fuel injector for cylinder 4.
This code indicates that the ECM has detected a low voltage condition in the high side circuit of the high-pressure fuel injector for cylinder 4. This could be due to a wiring issue, a faulty injector, or a problem with the ECM itself.
• Engine misfire
• Poor fuel economy
• Check engine light illuminated
• Faulty fuel injector
• Wiring or connection issues in the injector circuit
• Faulty engine control module (ECM)
ECM: Engine Control Module
Injector: A device that sprays fuel into the engine's cylinders
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for cylinder 4 injector.
• Test the injector for proper operation.
• Repair or replace damaged wiring or connectors.
• Replace the faulty injector.
• Replace or reprogram the ECM if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $500
Moderate
• Toyota Prius
• Lexus CT200h
• Toyota Camry Hybrid
• Regularly inspect and maintain fuel system components.
• Ensure proper fuel quality.
• Perform regular vehicle diagnostics.
Engine Performance
• Do not ignore the check engine light.
• Address any noticeable performance issues promptly.
Check with the vehicle manufacturer for specific warranty coverage related to the fuel system.
This code is often associated with hybrid vehicles that use high-pressure fuel systems.
Moderate – Address the issue to prevent further engine performance problems.
Driving with a misfiring engine can lead to increased emissions and potential engine damage.
• Engine at operating temperature
• Vehicle in a safe and stable condition
The fuel injector for cylinder 4 is located on the engine, typically on the intake manifold side.
Q: Can I drive with a P3158 code?
A: It's not recommended to drive for extended periods with this code, as it can lead to engine damage.
Q: How can I prevent this issue?
A: Regular maintenance and using high-quality fuel can help prevent injector issues.
High-End · Full-system diagnostics
A full-system bidirectional platform aimed at advanced DIY users and professional diagnostic workflows.
Network faults often require full-system access instead of a generic code reader alone.
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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.