P0280: Cylinder 7 Injector Circuit High
Engine may run rough, misfire on cylinder 7, reduced power and fuel economy
Overview
P0280 indicates that the onboard diagnostics has detected an abnormally high current/voltage in the fuel injector circuit for cylinder 7, often tied to wiring issues, faulty injector, or control module faults
Common Symptoms
- Check engine light illuminated
- Engine running rough or misfire on cylinder 7
- Reduced power/hesitation
- Decreased fuel economy
Most Common Causes
Injector internal short or coil failure can draw excessive current
Chafed/worn harness, corroded connector leading to high resistance
Loose, corroded terminals increase circuit resistance
Rare, but module driver circuitry can fail triggering high readings
Diagnostic Steps
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Retrieve P0280 and related codes with OBD-II scannerExpected: P0280 is present; related codes like P0207/P0307 may be presentInterpretation: Confirms injector circuit issue and potential misfire
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Visually inspect wiring harness and connectors for cylinder 7 injectorExpected: No damaged insulation, loose/corroded pinsInterpretation: Wiring/connectors integrity verified or faults noted
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Measure resistance of cylinder 7 injectorExpected: Resistance within OEM spec (typically low single digits)Interpretation: Higher/lower than spec suggests injector fault
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Check injector operation (audible click/bench test)Expected: Injector clicks and operates correctlyInterpretation: No sound suggests internal injector defect
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Check voltage at injector control pin during engine crankExpected: Voltage within manufacturer defined rangeInterpretation: Voltage out of range implicates wiring or PCM driver fault
Repair Solutions
Injector cost and labor vary by vehicle
Depends on extent and location of wiring damage
Dielectric grease and connector cleaning
Last resort after ruling out all wiring and injector faults
Common Misdiagnoses
Avoid these common diagnostic mistakes:
- Assuming general misfire without checking specific injector circuit
- Replacing fuel injector without verifying wiring/connectors
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