P0261 - Cylinder 1 Injector Circuit Low
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System
Powertrain (Engine & Gearbox)
Related Fault Codes
Technical Description
P0261 is stored when the Engine Control Module (ECM) detects a lower than expected voltage in the fuel injector control circuit for cylinder number 1. The ECM monitors the injector circuit by observing the voltage drop and current flow. When the ECM commands the injector 'ON' by grounding the circuit, it monitors the feedback. If the voltage remains low (potentially due to a short to ground or low internal resistance in the injector solenoid), or if the supply voltage is missing, the fault code is generated. This often results in the ECM disabling the injector or entering a limited operation mode to prevent engine and catalytic converter damage.
Possible Causes
Faulty fuel injector for cylinder 1 (internal short/low resistance)
Wiring harness issues (short to ground in the signal wire)
Corrosion or poor connection in the injector electrical connector
Faulty Engine Control Module (ECM) or software error
Symptoms
Recommended Solution
Workflow
Mechanic's Tip
Before replacing expensive components, always double-check wiring and connections. 80% of all sensor faults are actually due to corroded contacts or broken wires.
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