P0260: Cylinder 1 Injection Timing Circuit Malfunction - Causes, Fixes & Cost [2026]
What is P0260? P0260 is set when the PCM cannot command or verify proper injection timing on cylinder 1. On common-rail diesels and GDI engines this code points to injector driver problems, injector solenoid faults, or wiring issues that prevent the PCM from timing the injection event correctly.
🎯 Top 3 Causes Ranked by Probability
55%
#1 - Most Likely
Failed Cylinder 1 Injector
The injector solenoid or piezo stack has failed or has high resistance. Common after 100k miles on hard-worked diesels.
🔨 Part
$200-$800
👨🔧 Labor
$150-$500
⚡ DIY
Hard
30%
#2 - Check First
Wiring or Connector Fault
Chafed wiring or a corroded connector on the cylinder 1 injector circuit. Visually inspect and wiggle-test first.
🔨 Part
$10-$80
👨🔧 Labor
$80-$220
⚡ DIY
Medium
15%
#3 - Less Common
Failed PCM Injector Driver
The PCM driver transistor for cylinder 1 has failed. Confirmed only after injector and wiring are ruled out.
🔨 Part
$400-$1200
👨🔧 Labor
$150-$400
⚡ DIY
Hard
🔧 Step-by-Step Diagnosis
- Scan for companion misfire codes (P0301, P0263, etc.) - they confirm cylinder 1 is the affected cylinder.
- Measure injector solenoid resistance with the connector off. Most diesel injectors read 0.3-2.0 ohms; compare across all 4-8 injectors.
- Swap the cylinder 1 injector with another cylinder. If the fault moves with the injector, the injector is bad. If it stays, the harness or PCM is at fault.
- Back-probe the injector connector for proper drive signal with a scope or noid light during cranking.
- If injector and wiring test good, the PCM driver is suspect - confirm with a dealer scan tool before replacing.
🚗 Most Affected Vehicles
🚫 Is It Safe to Drive with P0260?
No. Driving with one injector misfiring or untimed can damage the catalytic converter or DPF and increase emissions sharply.
❓ Frequently Asked Questions
Will P0260 cause a misfire?
Yes. If cylinder 1 cannot inject fuel correctly it will misfire on every cold start and under load, often setting P0301 alongside P0260.
Can a bad injector damage my engine?
A stuck-open injector can wash oil off the cylinder wall and dilute the crankcase oil. A stuck-closed injector is less dangerous but still risks DPF or cat damage from raw fuel.
How much does it cost to fix P0260?
Wiring repairs are $90-$300. A single diesel injector replaced is $400-$1,200. PCM repairs run $550-$1,600 depending on the truck.
Should I replace all injectors or just one?
On high-mileage diesels with one failed injector, many shops recommend replacing the full set since the others are close behind. Get quotes both ways.
Can I clear P0260 and keep driving?
It will come right back, and you risk catalyst or DPF damage in the meantime. Have the truck towed if it sets repeatedly.