CAT 46 Fault Code: Engine Injector Cylinder #04 : Current Above Normal
Engine Injector Cylinder #04 : Current Above Normal · ai-assisted, editor-reviewed · Last updated 2026-07-21
TL;DR
CAT code 46, SPN 654 FMI 6, means the ECM detected high current flow, a short circuit, on the cylinder #04 injector solenoid circuit. The ECM disables that solenoid circuit to prevent damage but periodically retries firing the injector, so you may see this code repeat.
High severity. A shorted injector solenoid circuit means cylinder #04 is not firing reliably, which causes rough running, power loss, and possible misfire damage over time. It is not an immediate shutdown emergency but should be diagnosed before continued heavy-load operation.
What does CAT error code 46 mean?
This code applies to C13 and C15 engines with Electronic Unit Injectors (EUI). Each injector has its own solenoid, and the ECM sends 105 V pulses to each solenoid at the correct time and duration for the current engine load and speed.
The ECM continuously monitors current flow through each injector solenoid circuit. Code 46 sets specifically when the ECM detects high current flow, meaning a short circuit, on the cylinder #04 injector circuit. This is different from a low current (open circuit) condition, which would trigger a different code.
When the ECM sees the short, it disables that solenoid circuit to protect itself and the wiring from damage caused by the excess current. It does not just give up: the ECM periodically attempts to fire the injector again. If the short is still present, the disable-and-retry cycle repeats, which is why this code can log multiple times during a single trip.
Common causes of 46
- Failed injector: an internal short inside the injector solenoid itself.
- Wiring between the ECM and the valve cover: chafed, pinched, or damaged wiring shorting the signal circuit.
- Wiring under the valve cover for the injector harness: heat and vibration in this area can wear insulation and cause internal shorts.
- Plugged oil outlet port on the exhaust valve rocker arm: this can lead to conditions that stress the injector wiring or components near the rocker arm assembly.
How to troubleshoot CAT 46: first checks
- Run the engine to normal operating temperature before testing, since short circuits in injector wiring often only show up once things are warmed up.
- With the engine warm and under load or vibration if possible, carefully inspect the wiring and connectors between the ECM and the valve cover, and the injector harness wiring underneath the valve cover, looking for chafing, pinched insulation, or contact with grounded metal.
- Wiggle-test the harness and connectors while watching for the fault to reappear, since vibration-related shorts may not show up with the engine sitting still.
- Inspect the cylinder #04 injector connector for damage, corrosion, or moisture intrusion.
- Check the oil outlet port on the exhaust valve rocker arm for blockage.
- If wiring and connectors check out, test or swap the cylinder #04 injector to rule out an internally shorted solenoid.
How the code clears
No separate clearing step or reset procedure is listed for this code. Once the short circuit is repaired, whether that means fixing chafed wiring, cleaning or replacing a connector, clearing the plugged rocker arm oil port, or replacing the injector, the ECM should stop logging the fault as it resumes normal current monitoring on the circuit.
Affected models and serial ranges
46 appears in our records across 2 CAT models. Match your machine by model and serial number.
| Model | Serial ranges |
|---|---|
| C13 | Serial range not listed in source records |
| C15 | Serial range not listed in source records |
Frequently asked questions
What does CAT code 46 mean?
It means the ECM detected high current flow, a short circuit, on the injector solenoid circuit for cylinder #04. This is SPN 654 FMI 6 on C13 and C15 engines with electronic unit injectors.
Why does my machine keep throwing code 46 intermittently?
Short circuits caused by chafed wiring or a failing injector solenoid often only show up when the engine is warmed up or under vibration from heavy loads. The ECM also periodically retries firing the disabled injector, so the code can log again each time the short is still present.
Will code 46 cause the engine to shut down?
No, the ECM disables only the affected injector solenoid circuit to prevent damage, then keeps retrying. The engine keeps running but likely rough, with reduced power, since one cylinder is not firing correctly.
How is code 46 different from code 47?
Code 46 is a current above normal (short circuit) condition on the cylinder #04 injector circuit. Code 47 covers the cylinder #04 injector not responding properly, which is a different failure mode even though both involve the same injector.
Is code 46 related to code 42 or 49?
No. Code 42 covers a primary-to-secondary engine speed signal calibration issue, and code 49 covers low current on the inlet air heater circuit. Neither is part of the injector current diagnostic that triggers code 46.
What should I check first for code 46?
Start with the wiring between the ECM and the valve cover and the injector harness wiring underneath the valve cover, since these are the most common culprits, along with the injector itself and the oil outlet port on the exhaust valve rocker arm.