P0261 medium Severity

P0261: Cylinder 1 Injector Circuit Low

Check Engine Light illumination, possible rough idle, misfire and reduced engine performance.

Overview

P0261 indicates a low voltage condition in the injector control circuit for cylinder 1 as detected by the powertrain control module, typically caused by wiring issues, injector faults, or PCM driver circuit problems.

Common Symptoms

  • Check Engine Light illuminated
  • Rough idle or engine vibration
  • Misfire on cylinder 1
  • Reduced power or hesitation
  • Poor fuel economy

Most Common Causes

Faulty fuel injector (Cylinder 1) high

Internal failure or coil short can cause low voltage in the injector circuit.

Damaged or corroded wiring/connectors in injector circuit high

Corrosion, breaks, or shorts in wiring harness often trigger low voltage reading.

Poor ground or power supply to injector circuit medium

Loose ground straps or supply problems lower voltage to injector.

PCM/ECM injector driver circuit fault medium

Internal PCM driver transistor failure can mimic circuit low voltage.

Plugged or dirty injector affecting electrical characteristic low

Injector contamination may indirectly contribute but is primarily mechanical.

Diagnostic Steps

  1. Connect OBD-II scanner and confirm P0261 and check for related codes.
    Expected: Code P0261 stored; additional cylinder misfire codes may be present.
    Interpretation: Confirms low injector circuit condition for cylinder 1 and scopes further diagnostics.
  2. Visually inspect wiring and connectors to cylinder 1 injector.
    Expected: No corrosion, pin damage, or loose connections.
    Interpretation: Damaged or corroded wiring/connectors likely cause when found.
  3. Measure resistance of injector coil for cylinder 1 with multimeter.
    Expected: Resistance within manufacturer specification.
    Interpretation: Out-of-spec reading suggests injector failure.
  4. Check power supply and ground to injector circuit with ignition on.
    Expected: Proper reference voltage (e.g., ~12 V) and good ground continuity.
    Interpretation: Low voltage or poor ground indicates supply/ground issues.
  5. Perform continuity test from PCM driver pin to injector connector.
    Expected: Low resistance, no open circuit.
    Interpretation: High resistance/open indicates wiring harness fault.
  6. If all wiring and injector test good, assess PCM injector driver output or consider PCM reflash.
    Expected: PCM driver pulses present and within spec.
    Interpretation: Absence suggests PCM internal fault.

Repair Solutions

Replace defective cylinder 1 fuel injector medium
Estimated Cost: $150 - $400

Injector replacement when confirmed faulty.

Repair or replace damaged wiring/connectors medium
Estimated Cost: $50 - $200

Cleaning connectors, fixing harness shorts or opens.

Ensure good ground and power supply to injector circuit easy
Estimated Cost: $10 - $80

Tightening ground straps, cleaning grounds.

PCM reflash or replacement if injector driver fault hard
Estimated Cost: $500 - $1200

Last resort after all external diagnostics; professional service recommended.

Common Misdiagnoses

Avoid these common diagnostic mistakes:

  • Replacing fuel injector when the real issue is wiring or poor ground
  • Assuming mechanical fuel delivery problem without electrical testing

Frequently Asked Questions

What does the P0261 code mean?

Technically, the P0261 code represents Cylinder 1 Injector Circuit Low. It usually points to a fault within the Fuel System.

Can P0261 cause engine damage?

You should treat P0261 as a medium issue. Check Engine Light illumination, possible rough idle, misfire and reduced engine performance.

What are the symptoms of P0261?

Common symptoms include: Check Engine Light illuminated, Rough idle or engine vibration, Misfire on cylinder 1. You might also notice the Check Engine Light is on.

Potential causes for OBDII code P0261

Potential culprits include: Faulty fuel injector (Cylinder 1), Damaged or corroded wiring/connectors in injector circuit, Poor ground or power supply to injector circuit. A proper diagnosis is recommended.

How much does it cost to fix P0261?

Expect to pay around $80 if the issue is a Ensure good ground and power supply to injector circuit, but up to $1200 if the PCM reflash or replacement if injector driver fault needs replacement.

Is P0261 a generic or manufacturer-specific code?

P0261 is not specific to any one brand. It can appear on Ford, Dodge, Toyota, Honda, Jeep, and other vehicles.

User Comments (0)

Share your experience or ask a question about this code.

Be the first to share your experience with P0261!