P0262: Cylinder 1 Injector Circuit High
Possible rough idle, misfire on cylinder 1, reduced power and fuel economy, potential catalytic converter damage if unaddressed
Overview
P0262 indicates the engine control module has detected a high voltage or abnormal current condition in the cylinder 1 fuel injector circuit, typically due to wiring, injector, connector, or PCM driver issues
Common Symptoms
- Check Engine Light illuminated
- Rough idle or misfire at idle
- Loss of engine power or hesitation
- Reduced fuel economy
- Possible engine stalling or hard starting
Most Common Causes
Injector internal short or abnormal current draw causing high voltage reading
Short to voltage or high resistance in injector circuit
Poor connection can elevate voltage in circuit
Rare but possible cause of high voltage detection
Diagnostic Steps
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Connect a professional OBD-II scan tool and confirm P0262, recording any freeze-frame data and additional codesExpected: P0262 code present, possibly alongside misfire codes like P0301Interpretation: Confirms primary injector circuit fault
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Visually inspect injector wiring harness and connectors for cylinder 1 for damage, corrosion, or loose terminalsExpected: No visible damage or corrosionInterpretation: If damage is found, repair wiring/connector then retest
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Measure injector resistance with multimeter, comparing to OEM specExpected: Resistance within specification (varies by vehicle)Interpretation: Out-of-spec suggests faulty injector
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Perform voltage measurement at injector connector with engine running and commanded injector pulseExpected: Typical battery voltage (~12–14V)Interpretation: Significant above normal indicates high circuit condition
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If wiring and injector test good, test for shorts/opens to power or ground in circuit and check PCM driver outputExpected: No shorts/abnormal readingsInterpretation: If abnormal, consider PCM inspection or replacement
Repair Solutions
Cleaning and securing connections can often resolve high circuit condition
Injector internal faults are a frequent root cause
Only after confirming all external circuit faults are resolved
Common Misdiagnoses
Avoid these common diagnostic mistakes:
- Assuming fuel injector mechanical clog or fuel pressure issue without electrical testing
- Interpreting related misfire codes as separate issue when they stem from this injector circuit fault
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