Cylinder 1 Injector Circuit Low
The P0261 code indicates that the Engine Control Module (ECM) has detected a low voltage or current condition in the electrical circuit of the fuel injector for cylinder 1. This typically means the injector's resistance is too low, there is a short to ground in the wiring, or the injector driver circuit in the ECM is faulty. The injector may not open properly, causing a lean condition, misfire, and reduced engine performance.
1. Most Common Causes
- Cylinder 1 injector has internal short circuit or low resistance
- Injector control circuit (PWM/ground) shorted to ground
- Injector voltage supply circuit open or high resistance
- Injector connector damaged, loose, or corroded
- Internal injector driver failure in PCM/ECM
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine misfire or rough idle
- Reduced power and poor fuel economy
- Possible hard starting or stalling
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect injector connector and wiring for damage or corrosion.
Step 3: Measure resistance of cylinder 1 injector (should be 11-18 ohms; low indicates short).
Step 4: Check for voltage at injector connector with key on (should be battery voltage).
Step 5: Perform a continuity test from injector connector to ECM to check for shorts to ground.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can cause catalytic converter damage from unburned fuel. Short trips to a repair shop are acceptable.
How much does it cost to fix?▼
Repair costs vary: injector replacement $150-$300, wiring repair $100-$200, ECM replacement $500-$1000. Diagnosis typically $100-$150.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.