OBD-II Code · Fuel & Air
P0261
Cylinder 1 Injector Circuit Low
Severity
high
Left alone, this one tends to take other parts with it.
Can you drive it
Not for long
Driving on this one risks further damage. Get it to a shop rather than carrying on with it.
Indicative cost (USD)
$100–$500
Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
Cyl 1 injector circuit voltage low.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then work the likely-causes list in the order shown.
That order is what a shop checks first for this code — wiring and connections before the component they run to, because a connector costs nothing to inspect and is a common answer.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Misfire cyl 1
- Check engine light
Likely causes
- Failed injectorMost common
- Wiring short to ground
Read the full diagnostic procedureP0261 sets when the ECM driver detects current through the cylinder 1 injector circuit below the expected threshold during pulse-width commands, indi…
P0261 sets when the ECM driver detects current through the cylinder 1 injector circuit below the expected threshold during pulse-width commands, indicating a short to ground on the injector low-side circuit, a shorted injector winding pulling excessive current, or a failed ECM injector driver.
Cheapest-first ladder
- with the engine off and key on, unplug the cylinder 1 injector and ohm the injector coil across its two pins — a healthy saturated-driver injector reads 11-17 ohms (Bosch EV6/EV14 typical), a peak-and-hold low-impedance reads 1.5-4 ohms; reading under 1 ohm confirms a shorted winding.
- Inspect the harness from the injector connector back along the intake manifold and against the cylinder head for chafe spots — the cylinder 1 injector harness on V-engines often runs against the timing cover edge.
- Use a noid light or current-clamp on the injector control wire to confirm the ECM is still attempting to fire; if no pulse is present after the harness checks clean, the ECM driver has failed.
- Caveat: P0261 will not always set a misfire code immediately because the ECM may disable the driver to protect itself — do not assume the cylinder is firing just because the engine runs.
Vehicle-specific patterns2007-2013 Chevy Silverado/Tahoe 5.3L (LMG/LC9) — injector harness chafe against the intake manifold mounting boss on cylinder 1, repair harness and a…
- 2007-2013Chevy Silverado/Tahoe 5.3L (LMG/LC9) — injector harness chafe against the intake manifold mounting boss on cylinder 1, repair harness and apply protective loom; full injector replacement (Multec part 12613411) only if winding ohms confirm short.
- 2005-2010Ford F-150 5.4L 3V — injector connector pin corrosion on cylinder 1 from valve cover gasket seep, clean and replace pigtail.
- 2006-2012Toyota Tacoma 4.0L (1GR-FE) — cylinder 1 injector internal short under TSB EG028-09, replace injector 23250-31020.
- 2007-2013Dodge Ram 1500 5.7L Hemi — injector driver failure inside PCM on bank 1, PCM replacement and reflash with security key.
Estimated repair$80 to $900.
Look up another code
P0261 — frequently asked
What does a P0261 code mean?
Cyl 1 injector circuit voltage low.
What causes a P0261 code?
Common causes: Failed injector; Wiring short to ground.
What are the symptoms of a P0261 code?
Typical symptoms: Misfire cyl 1; Check engine light.
Is it safe to drive with a P0261 code?
Not for long. Driving on this one risks further damage. Get it to a shop rather than carrying on with it. Estimated repair: $100-$500.
How do I diagnose a P0261 code?
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed. 1. Note every code that is set, not just this one. 2. Read the freeze frame — the conditions the fault was recorded under. 3. Confirm the fault is current rather than history. 4. Then work the likely-causes list in the order shown.
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