Cylinder 2 Injector - Current Below Normal / Open Circuit
The CAT-INJ2-FMI5 (Caterpillar) diesel fault code means: Cylinder 2 Injector - Current Below Normal / Open Circuit. This is a serious severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- advanced
- Estimated cost
- $400-$1800
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Common Symptoms
- Check Engine Light with rough idle
- Dead cylinder / misfire on affected cylinder
- Power loss and black/white smoke
- Engine derate
Probable Causes (Ranked by Likelihood)
- Injector solenoid coil open Very Likely
- Open wire from ECM to injector Likely
- Connector pin issue at valve cover pass-through Likely
Step-by-Step Diagnostic Procedure
With CAT ET, run cylinder cutout test; the affected cylinder will not change RPM.
Remove valve cover; inspect injector wiring for chafe, disconnected pins, or corrosion.
Ohm the injector solenoid per CAT spec (typically under 1 ohm). Open reading confirms coil failure.
Replace injector if coil is open; repair harness if wire is open.
Frequently Asked Questions
What does CAT code INJ2-FMI5 mean?
CAT code INJ2-FMI5 (Cylinder 2 Injector - Current Below Normal / Open Circuit) is a serious-severity fault on Caterpillar on-highway diesel engines. This code flags cylinder 2 injector fault. CAT on-highway engines use HEUI (hydraulically actuated) injection pre-2007 and common rail post-2007. Confirm with CAT ET cylinder cutout test before replacing a $500-$800 injector. Diagnose with CAT ET (Electronic Technician) software.
Can I drive my truck with CAT code INJ2-FMI5?
Short distances may be acceptable, but running long with this fault risks progressive damage or forced derate. Address promptly.
How much does it cost to fix CAT INJ2-FMI5?
Typical repair is $400-$1800. Sensor / wiring fixes fall at the low end; injector, HEUI pump, turbo, or aftertreatment work falls at the high end. CAT dealer labor often requires CAT ET for calibration and parameter programming.
Sources
This page is built from documented references. Verify against your own service info before repair work.