P0277 - Cylinder 6 Injector Control Circuit High
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System
Powertrain (Engine & Gearbox)
Related Fault Codes
Technical Description
P0277 is a diagnostic trouble code (DTC) that indicates the Engine Control Module (ECM/PCM) has detected a high voltage condition in the fuel injector control circuit for cylinder number 6. This typically points to a short to voltage (B+) within the wiring harness or the injector's internal coil. The ECU monitors the feedback voltage from the injector driver; if the voltage remains at a high state when it should be pulled low, the logic triggers the fault. This fault can lead to the ECU disabling the injector for that cylinder to prevent engine damage or catalytic converter overheating.
Possible Causes
Short to voltage in the wiring harness for cylinder 6 injector
Faulty fuel injector (internal short circuit)
Corroded or damaged connector at the injector
Internal ECM/PCM hardware failure
Symptoms
Recommended Solution
- STEP 1: Visually inspect the wiring harness for injector 6 for any signs of chafing or melted insulation causing a short to voltage.
- STEP 2: Disconnect the injector and measure the internal coil resistance. Standard values are usually between 10–16 Ohms. Also check for continuity between terminal and injector body (should be infinite).
- STEP 3: Use a multimeter to check for voltage at the connector with ignition on. If constant battery voltage is present on the control wire, there is a short to voltage in the harness.
- STEP 4: Use an oscilloscope to monitor the injector pulse. A constant 'high' signal indicates a faulty ECU driver or wiring short.
- STEP 5: Replace the fuel injector or repair the wiring harness as necessary. Clear codes and perform a test drive.
Mechanic's Tip
Before replacing expensive components, always double-check wiring and connections. 80% of all sensor faults are actually due to corroded contacts or broken wires.
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