P0291 Cylinder 11 Fuel Injector Control Circuit Low

P0291 – OBD-II Trouble Code Technical Description

Trouble code P0291 indicates a low signal in the cylinder 11 fuel injector control circuit.

What does the fault code mean P0291?

Trouble code P0291 indicates that the PCM has detected that the cylinder 11 fuel injector control circuit voltage is too low compared to the manufacturer's specification.

Possible reasons

Some possible reasons for the P0291 trouble code:

• Defective Fuel Injector: A damaged or clogged injector can result in poor fuel atomization, causing the circuit to drop in voltage.
• Electrical Connection Problems: Loose connections or breaks in the electrical circuit, including wires and connectors, can cause voltage drops.
• PCM Problems: A defect or malfunction in the engine control module (PCM) firmware can cause the fuel injector to not control properly, resulting in a P0291 code.
• Insufficient Fuel Pressure: Problems with the fuel pump or fuel pressure regulator can cause insufficient fuel pressure, resulting in low voltage in the circuit.
• Fuel filter problems: A clogged fuel filter can restrict the flow of fuel to the injectors, which can also cause low voltage.
• Fuel system problems: Improper operation or damage to other fuel system components, such as pressure regulators or valves, can also cause P0291.

What are the symptoms of a fault code? P0291?

Some possible symptoms when trouble code P0291 appears:

• Loss of power: The most common symptom is loss of engine power. This may manifest itself in weakened acceleration or insufficient response to pressing the gas pedal.
• Unstable idle: You may experience rough idling or even heavy jolting when parked.
• Unstable engine performance: There may be jumps in engine speed or uneven operation when driving.
• Increased fuel consumption: If the engine is experiencing problems with the fuel injector, it may result in increased fuel consumption.
• Black smoke from the exhaust pipe: If there is insufficient fuel supply to the cylinders, black smoke may be observed from the exhaust pipe, especially when accelerating or idling.
• Check Engine light on: The appearance of the Check Engine light on the dashboard is one of the main signs of a possible problem.

How to diagnose a fault code P0291?

To diagnose DTC P0291, the following steps are recommended:

1. Scan error code: Use the diagnostic scan tool to read the error code and obtain additional information about the status of the fuel injection system.
2. Checking the fuel system: Check the fuel system for leaks, damage or blockages. Make sure fuel filters are not clogged and fuel lines are not damaged.
3. Checking the fuel injector: Assess the condition of the cylinder 11 fuel injector. Check its resistance and ensure that it is functioning correctly. Replace the fuel injector if necessary.
4. Checking electrical connections: Check the electrical connections in the fuel injector control circuit. Make sure all contacts are clean, dry and well connected.
5. Fuel pressure check: Check the fuel pressure in the injection system. Make sure the pressure meets the manufacturer's specifications.
6. Check PCM: If all the above steps fail to identify the problem, the problem may be with the PCM itself. In this case, additional diagnostics or replacement of the engine control unit will be required.
7. Additional tests: If necessary, perform additional tests such as an ignition system test or a compression test on cylinder 11.

Remember that to accurately diagnose and fix the problem, it is better to contact a qualified auto mechanic or service center.

Diagnostic errors

When diagnosing DTC P0291, the following errors may occur:

• Insufficient fuel injector check: If you do not properly check the condition of the cylinder 11 fuel injector, you may miss the presence of a problem with that injector, which will result in the need for additional diagnostics and repairs.
• Insufficient checking of electrical connections: Failure to thoroughly check the electrical connections in the fuel injector control circuit may result in misinterpretation of the cause of the error and the replacement of components that might otherwise be OK.
• Skip fuel pressure check: Not checking the injection system fuel pressure may cause problems with the fuel pump or fuel pressure regulator to be missed, which could be the cause of P0291.
• Incorrect interpretation of scanner data: Incorrect reading of the scanner data or misinterpretation of the fuel injection system parameters can lead to erroneous diagnosis and incorrect determination of the cause of the P0291 code.
• Skip PCM check: It is important to ensure that the engine control module (PCM) is in good working order, as a faulty PCM may also be the cause of P0291. Skipping this step may lead to ineffective diagnosis and replacement of unnecessary components.

To avoid these errors, it is recommended to carry out a complete and thorough diagnosis using the correct equipment and methods. If necessary, it is better to contact professionals to accurately identify and eliminate the problem.

How serious is the fault code? P0291?

Trouble code P0291 indicates a voltage problem in the cylinder 11 fuel injector circuit, which may result in insufficient fuel delivery to the engine. This may affect engine performance, performance and efficiency. Although the engine may continue to run, insufficient fuel can cause reduced power, rough operation, and other problems. Therefore, code P0291 should be taken seriously and the problem addressed promptly

What repair will help eliminate the code? P0291?

To resolve DTC P0291, the following steps are recommended:

1. Check Electrical Circuit: Check the cylinder 11 fuel injector power and ground circuit for damage, corrosion, or breaks. If necessary, replace damaged wires or connectors.
2. Check Fuel Injector: Check the condition of the cylinder 11 fuel injector for blockages or damage. Clean or replace the nozzle if necessary.
3. Check fuel pressure: Check the fuel pressure in the fuel injection system. Low pressure may cause insufficient fuel supply.
4. Check Engine Control Module (PCM): Check the engine control module for faults or damage. Replace or reprogram the PCM as necessary.
5. Check Sensors: Check sensors that may affect fuel system performance, such as the fuel pressure sensor or crankshaft position sensor.
6. Perform a software update: In some cases, the problem may be related to the PCM software. A software update may resolve this issue.

If you are unsure of your automotive repair skills, it is recommended that you contact a qualified auto mechanic for diagnosis and repair.

P0291 Cylinder 11 Injector Circuit Low 🟢 Trouble Code Symptoms Causes Solutions

P0291 – Brand-specific information

Trouble code P0291 can occur on different makes of vehicles. Here are some of them with their transcripts:

1. Ford: High pressure fuel injector 11 - voltage too low.
2. Chevrolet: Fuel injector 11 voltage low.
3. Dodge: Fuel injector 11 circuit voltage is too low.
4. BMW: Cylinder 11 fuel injector voltage low.
5. Toyota: Fuel injector 11 voltage is below the set level.

These are just some of the possible makes of vehicles where the P0291 code may occur. The exact interpretation of the code may vary slightly depending on the model and year of the vehicle. Therefore, for more accurate information, it is recommended to contact your dealer or certified mechanic.