Cylinder 6 Injector Circuit High
The P0277 code indicates that the powertrain control module (PCM) has detected a high voltage or resistance in the electrical circuit for the fuel injector on cylinder 6. This typically means the injector circuit is open or has excessive resistance, often due to a faulty injector, damaged wiring, or a poor connection. The PCM monitors the injector driver circuit and sets this code when the voltage is above the expected range.
1. Most Common Causes
- Cylinder 6 fuel injector with high internal resistance or open coil
- Injector circuit wiring shorted to battery voltage (Vbat or Vcc)
- Corroded, loose, or oxidized injector connector or terminal
- Partial wiring break or harness damage increasing circuit resistance
- Internal ECM/PCM injector driver failure (less common)
- Injector circuit ground issue altering voltage reference
2. Symptoms You Will Notice
- Engine misfire on cylinder 6
- Rough idle or hesitation
- Check Engine Light illuminated
- Reduced fuel economy and performance
3. Step-by-Step Diagnosis
Step 1: Scan for codes and verify P0277 is present.
Step 2: Visually inspect the injector connector and wiring for damage or corrosion.
Step 3: Measure resistance of cylinder 6 injector; compare to specification (typically 12-16 ohms).
Step 4: Check for voltage at the injector connector with key on; should see battery voltage.
Step 5: Perform a continuity test from the injector connector to the PCM.
Step 6: If wiring and injector check out, test the PCM injector driver (may require professional scan tool).
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as the misfire can damage the catalytic converter and cause poor performance. Short trips to a repair shop are acceptable.
How much does it cost to fix?▼
The cost typically ranges from $150 to $400, including parts and labor. A new injector costs $50-$150, and labor is 1-2 hours.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.