CAT Engine 2674 Fault Code: Remote Shutdown Input : Voltage Below Normal
Also called Remote Shutdown Input - Voltage Below Normal, Remote Shutdown Input short to ground, Remote Shutdown Input voltage below normal, Remote Shutdown Input:Voltage Below Normal, Remote Shutdown Switch Voltage Below Normal
Remote Shutdown Input : Voltage Below Normal · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
CAT code 2674 sets when the ECM sees both contacts of the ground level shutdown switch closed at the same time, which reads as a voltage below normal on the remote shutdown circuit. It affects C13, C15, C18, C27, and C32 engines. The engine keeps running if it was already running, but it will not restart until the switch is back in RUN and the ECM has been power cycled.
Medium severity. The engine does not shut down on its own when this code sets while running, so it is not an immediate stop-now situation. But it can leave you stranded with a no-start condition until the switch position and wiring are sorted out, so it should be diagnosed promptly rather than ignored.
What does CAT Engine error code 2674 mean?
Fault code 2674 relates to the ground level shutdown switch, sometimes called the remote shutdown switch. This switch lets someone outside the cab shut the engine down in an emergency by flipping it to the SHUTDOWN or STOP position under the red cover guard.
The ECM monitors two switch contacts. Normally these contacts are in opposite states. Code 2674 sets when both contacts read closed at the same time, which the ECM interprets as a voltage below normal on that circuit, and it may also indicate a short to ground in the wiring.
When the code is active and the engine is running, the engine continues to run and the code is simply logged. But the ECM will not allow a restart until the switch is confirmed in the RUN position and, depending on which control logic is present, until engine rpm is zero or the ECM power has been cycled. The status screen may show 'INJECTION DISABLED' and 'REMOTE SHUTDOWN' when the switch is actually in the shutdown position.
Common causes of 2674
- Connectors, pins, or sockets at the switch or ECM are not fully coupled or inserted
- Corrosion, abrasion, or pinch points in the wiring harness between the switch and the ECM
- The ground level shutdown switch itself is faulty or not operating normally and needs replacement
- A short in the wiring between the ground level shutdown switch and the ECM P1 connector
- An intermittent electrical problem in the harness
- A fault with the ECM itself
How to troubleshoot CAT Engine 2674: first checks
- Confirm the ground level shutdown switch is physically in the RUN position, not SHUTDOWN or STOP, under the red cover guard
- Inspect the switch connector and ECM connector (including the P1 connector) for pins that are not fully seated, corrosion, or damage
- Trace the harness between the switch and the ECM looking for pinch points, chafing, or abrasion damage
- Check the switch contacts for proper operation by testing continuity through both positions, since the switch itself may need replacement
- If wiring and switch check out, consider an intermittent connection issue or an ECM-side fault
How the code clears
No separate clearing step is listed beyond correcting the wiring, connector, or switch fault. To restore normal engine starting, return the ground level shutdown switch fully to the RUN position and cycle the electrical power to the ECM. On some control logic, engine rpm must also be at zero before the ECM will allow a restart.
Affected models and serial ranges
2674 appears in our records across 5 CAT Engine 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 |
| C18 | Serial range not listed in source records |
| C27 | Serial range not listed in source records |
| C32 | Serial range not listed in source records |
Frequently asked questions
What does CAT code 2674 mean?
It means the ECM detected both contacts of the ground level (remote) shutdown switch closed at the same time, which reads as a voltage below normal on that circuit. This is tied to SPN 4215 FMI 4.
Will code 2674 shut down my CAT engine?
Not by itself. If the engine is already running when the code sets, it continues to run and the code is just logged. The bigger issue is that the ECM may refuse to allow a restart until the switch and wiring are corrected.
Why won't my engine restart after this code appears?
The ECM requires the ground level shutdown switch to be in the RUN position, and in some cases requires the electrical power to the ECM to be cycled and engine rpm to be zero, before it will allow fuel injection and a restart.
What is the ground level shutdown switch?
It is a switch, usually under a red cover guard outside the cab, that lets someone shut the engine down from ground level in an emergency by disabling fuel injection through the ECM.
What are the most common causes of code 2674?
Loose or unseated connectors, corrosion or pinch points in the wiring harness, a faulty shutdown switch that needs replacement, a short between the switch and the ECM connector, and less commonly a fault in the ECM itself.
Can I keep operating the machine with this code active?
You can typically keep running if the engine was already running when the code set, but you should diagnose it as soon as possible since a no-start condition can strand the machine, and the underlying wiring or switch fault could get worse.
Does this code affect engine performance?
Some versions of this diagnostic note there are no performance effects while the engine runs. The main operational impact is the restart restriction until the fault is corrected.