Cylinder 5 Injector Circuit High (Diesel Variant)
What does P0276 mean?
The P0276 code means the vehicle's onboard diagnostic system has detected: Cylinder 5 Injector Circuit High (Diesel Variant). This is a moderate severity code.
Common Symptoms
- Engine misfire on cylinder 5
- Rough idle and vibration
- Check Engine Light illuminated
- Excessive white or black smoke from exhaust
- Knocking sound from engine
Probable Causes (Ranked by Likelihood)
- Open circuit in cylinder 5 injector high-side wiring Very High
- Faulty cylinder 5 fuel injector (excessive return flow) High
- Corroded injector connector causing high resistance High
- Damaged injector wiring harness Moderate
- PCM injector driver circuit fault Low
Step-by-Step Diagnostic Procedure
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Measure cylinder 5 injector resistance and compare to manufacturer specification
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Perform an injector return flow test on diesel engines -- excessive return flow indicates a worn injector
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Check for 12V power and proper ground at the injector connector
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Inspect the injector harness for heat damage or chafing near exhaust components
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Replace the injector if electrical or flow tests confirm failure
Frequently Asked Questions
Can I drive with code P0276?
You can drive short distances. On diesel engines, a faulty injector can cause white smoke and rough running. Prolonged driving risks damage to the DPF and catalytic converter.
What is an injector return flow test?
On diesel engines, fuel injectors return unused fuel to the tank. A return flow test measures how much fuel leaks past the injector internals. Excessive return flow indicates worn injector components.
Are diesel injectors more expensive than gasoline injectors?
Yes. Diesel injectors operate at much higher pressures (up to 30,000 PSI on common rail systems) and are precision-machined components. Individual diesel injectors can cost $200-$500 each.