P0261: Cylinder 1 Injector Circuit Low - Causes, Fixes & Cost [2026]
What is P0261? P0261 means the injector control wire for cylinder 1 is showing low voltage when the PCM commands the injector to fire. Causes include a shorted injector solenoid, a wire shorted to ground, or a failed PCM driver.
🎯 Top 3 Causes Ranked by Probability
50%
#1 - Most Likely
Shorted Injector (Cyl 1)
Injector solenoid coil has shorted internally and pulls the control wire to ground. Resistance check confirms.
🔨 Part
$80-$600
👨🔧 Labor
$100-$350
⚡ DIY
Medium
35%
#2 - Check First
Control Wire Shorted to Ground
A chafed injector wire is grounding against the head or harness clip. Visual inspection is critical.
🔨 Part
$10-$80
👨🔧 Labor
$80-$220
⚡ DIY
Medium
15%
#3 - Less Common
PCM Injector Driver Fault
Internal short in the PCM driver for cylinder 1. Diagnosed by elimination.
🔨 Part
$400-$1200
👨🔧 Labor
$150-$400
⚡ DIY
Hard
🔧 Step-by-Step Diagnosis
- Measure cyl 1 injector resistance. Most gas injectors read 11-17 ohms; diesels read 0.3-2 ohms. Anything below spec means a shorted coil.
- Disconnect the injector and check whether the code clears - confirms the short is in the injector, not the harness.
- With the injector unplugged, check the control wire for continuity to ground. Any continuity means a shorted harness.
- Compare with a known-good injector by swapping it to cyl 1 and seeing if the fault follows the injector.
- If injector and wiring are good, the PCM driver is the cause - confirm with a dealer or a known-good PCM swap.
🚗 Most Affected Vehicles
🚫 Is It Safe to Drive with P0261?
No. Cylinder 1 may not be firing at all, which causes a strong misfire, raw fuel into the cat, and possible converter damage within hours.
❓ Frequently Asked Questions
Will P0261 trigger a misfire code?
Yes, P0301 (cyl 1 misfire) usually sets alongside P0261. The injector cannot fire, so the cylinder is dead.
How do I know if the injector or the wire is bad?
Resistance test the injector with it unplugged. If the injector is shorted (resistance below spec), replace it. If the injector is fine but the harness shows a short to ground, fix the wire.
Can I keep driving with P0261?
No. Raw fuel from a misfiring cylinder will overheat and destroy the catalytic converter in a few hours of driving.
What is the resistance of a good fuel injector?
Most gasoline saturated injectors read 11-17 ohms. Peak-and-hold injectors read 1-3 ohms. Diesel solenoid injectors read 0.3-2 ohms. Check your specific spec.
Will replacing the injector fix P0261?
If the injector tested shorted, yes. If the wire is the problem, a new injector will read the same low voltage and the code will return immediately.