Cylinder 9 Injector Circuit High
The P0286 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 9. This typically means the injector circuit is shorted to voltage or has excessive resistance, preventing proper injector operation. Common causes include a faulty injector, damaged wiring, or a poor connection.
01. Most Common Causes
- Faulty fuel injector on cylinder 9
- Short to voltage in injector wiring or connector
- Open or high resistance in the injector circuit
- Corroded or damaged injector connector
- Failed PCM (rare)
02. Symptoms You Will Notice
- Engine misfire on cylinder 9
- Rough idle or hesitation
- Check Engine Light illuminated
- Reduced fuel economy
- Possible engine knocking
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm the code and check for additional codes.
Step 2: Visually inspect the injector connector and wiring for damage, corrosion, or shorts.
Step 3: Measure resistance of cylinder 9 injector; compare to manufacturer specs (typically 12-16 ohms).
Step 4: Check for voltage at the injector connector with key on; should be battery voltage on one pin.
Step 5: Perform a injector balance test or use a noid light to verify injector pulse.
Step 6: If all checks pass, suspect a PCM issue; test or replace PCM.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code as it can cause engine misfire, catalytic converter damage, and reduced performance. Have it diagnosed promptly.
How much does it cost to fix?▼
Repair costs vary: injector replacement $150-$400, wiring repair $100-$300, PCM replacement $500-$1000. Diagnosis fee typically $100-$150.