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 the computer in your car is having trouble sending the right amount of fuel into one of the engine's cylinders. It's like trying to fill a cup with a straw that has a hole in it.
The P0291 code indicates that the fuel injector circuit for cylinder 11 is experiencing low voltage, which can affect the injector's ability to deliver fuel properly.
The Engine Control Module (ECM) monitors the fuel injector circuit for each cylinder. When it detects that the voltage in the injector circuit for cylinder 11 is lower than expected, it sets the P0291 code. This can lead to improper fuel delivery and engine performance issues.
• Engine misfire
• Rough idling
• Reduced engine performance
• Faulty fuel injector
• Wiring issues in the injector circuit
• Bad connection or corrosion at the injector connector
Fuel Injector: A component that sprays fuel into the engine's cylinders.
ECM: Engine Control Module, the computer that controls engine functions.
• Use an OBD-II scanner to confirm the P0291 code.
• Inspect the wiring and connectors for cylinder 11's injector.
• Test the injector for proper operation and resistance.
• Repair or replace damaged wiring or connectors.
• Replace the faulty fuel injector.
• Clean connections to ensure proper electrical contact.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $400
Moderate
• Ford F-150
• Chevrolet Silverado
• Dodge Ram
• Regular maintenance and inspection of fuel injectors.
• Ensure electrical connections are clean and secure.
• Use quality fuel to prevent injector clogging.
Engine Performance
• Do not ignore the check engine light.
• Get the vehicle checked by a professional if you're not experienced.
• Avoid driving the vehicle extensively until the issue is resolved.
Check with your vehicle manufacturer for warranty coverage on fuel injectors.
This code has been historically associated with injector circuit issues, often due to wiring problems or injector failure.
Moderate – Should be addressed soon to avoid further engine performance issues.
Driving with a misfiring engine can lead to increased emissions and potential safety risks.
• Engine running
• Warm up the engine to operating temperature
The fuel injector for cylinder 11 is located on the engine's cylinder head, typically accessible by removing the engine cover.
Q: Can I drive with a P0291 code?
A: It's not recommended to drive extensively with this code, as it can lead to engine damage and poor performance.
Q: How do I know if my injector is faulty?
A: Symptoms like engine misfires, rough idle, and poor fuel economy can indicate a faulty injector.
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.
View on Amazon
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.
View on Amazon
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.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.
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.
View options on Amazon
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.