The P0271: Cylinder 4 Injector Circuit High refers to a situation where an abnormally high voltage is detected in the injector circuit for Cylinder 4. This condition can arise due to a faulty fuel injector, wiring issues like shorts or opens, or a malfunction in the Powertrain Control Module (PCM). When this code is triggered, it indicates that Cylinder 4 may be receiving too much voltage, which can affect the fuel delivery and overall engine performance.
P0271 – Quick Overview
| Meaning | P0271: Cylinder 4 Injector Circuit High |
| Is it serious? | Yes, this code can be serious as it may cause improper fuel delivery, potentially leading to engine misfires, rough running, and reduced fuel efficiency. |
| Possible causes | – High voltage in the injector circuit for Cylinder 4 – Faulty fuel injector for Cylinder 4 – Wiring issues such as shorts or opens – Faulty PCM |
| How to diagnose? | – Test the injector circuit for Cylinder 4 for proper operation. – Check for high voltage in the circuit. – Inspect the wiring and connectors for defects. – Replace or repair any faulty components. |
P0271 Meaning
The P0271: Cylinder 4 Injector Circuit High means that there is an issue with the electrical circuit controlling the fuel injector for Cylinder 4, specifically involving a high voltage condition. This could be caused by a malfunctioning injector, damaged wiring, or a problem with the PCM. When this code is present, it indicates that the fuel injector for Cylinder 4 might be receiving too much voltage, which can disrupt proper engine performance.
Step-by-step diagnostic guide
Follow the outline procedure to diagnose this DTC by eliminating possible causes one by one.
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use an OBD-II scanner to check if there are any other related codes present. These might give additional clues about the problem. | OBD-II Scanner |
| Test the Injector Circuit for Cylinder 4 | Measure the voltage in the injector circuit for Cylinder 4 using a multimeter. Compare the readings to the manufacturer’s specifications to ensure they are within range. | Multimeter, Manufacturer’s Specifications |
| Inspect the Cylinder 4 Fuel Injector | Visually inspect the fuel injector for Cylinder 4 for any signs of damage, corrosion, or disconnection. Ensure it is securely attached and functioning properly. | Flashlight, Safety Gloves |
| Inspect Wiring and Connectors | Carefully examine the wiring and connectors associated with the fuel injector for Cylinder 4. Look for signs of wear, damage, shorts, or open circuits. | Flashlight, Multimeter |
| Repair or Replace Faulty Components | If any wiring, connectors, or components are found to be faulty during the inspection, repair or replace them as necessary. Ensure all connections are secure and free from contaminants. | Wire Strippers, Electrical Tape, Replacement Wires/Connectors |
| Check the PCM (Powertrain Control Module) | Inspect the PCM and its connections for any signs of damage or loose connections. If the PCM is suspected to be faulty, it may need reprogramming or replacement. | OBD-II Scanner, Multimeter |
| Clear the Code and Test Drive | After completing the necessary repairs, clear the P0271 code using the OBD-II scanner. Take the vehicle for a test drive to ensure the issue is resolved and the code does not return. | OBD-II Scanner, Vehicle Owner’s Manual |
| Recheck for Codes | After the test drive, re-scan the vehicle to ensure the P0271 code has not reappeared. If the code returns, further diagnosis may be required. | OBD-II Scanner |
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I test OBD-II scanners and make DIY Engine diagnostics guides to help you solve your car problems without having to depend on the mechanic. A lot of them will try to scam you or are just no help at all. About Juraj Lukacko