CAT Engine 211 Fault Code: Cylinder #2 Injector fault
Also called Cylinder #2 Injector Fault, Injector Cylinder #2 fault
Cylinder #2 Injector fault · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
CAT fault code 211 means the ECM detected an open or short circuit in the cylinder #2 injector circuit while trying to operate it, on C10, C12, C15, and C16 engines. Expect engine misfires and low power, and possibly a second cylinder affected if the shared common wire is at fault.
High severity. This code drives engine misfires and low power right away, and since the injector common wire is shared, a wiring fault can knock out two cylinders at once. It should be diagnosed promptly, though it is not an immediate shutdown emergency.
What does CAT Engine error code 211 mean?
Fault code 211 (SPN 652, FMI 11) means the Electronic Control Module tried to fire the cylinder #2 injector and detected an electrical problem in that injector's circuit, either an open circuit, a short to ground, or a short to battery voltage.
This code applies to CAT C10, C12, C15, and C16 engines. Because injectors on these engines share a common wire between certain cylinders, a fault in that shared wiring can affect two cylinders simultaneously, not just cylinder #2 alone.
The ECM logs the code and keeps trying to operate the injector afterward, but the injector may not fire correctly while the fault is present. This shows up to the operator as engine misfire and a noticeable loss of power.
Common causes of 211
- Damaged or corroded connectors and/or wiring in the injector circuit
- A problem in the engine or injector wiring harness
- A short in the injector harness, including a short to ground
- A mechanical problem in the cylinder itself
- A faulty or failing injector solenoid
- A faulty or worn-out injector that needs replacement
- An intermittent electrical problem that comes and goes
- A faulty ECM (less common, but listed as a possible cause)
How to troubleshoot CAT Engine 211: first checks
- Retrieve the active and logged fault codes and confirm code 211 is current, not just historical.
- Inspect the cylinder #2 injector connector and wiring for corrosion, damaged pins, chafing, or loose connections.
- Since injectors share a common wire, check whether a neighboring cylinder is also misfiring or showing a related code, this points to a common-wire problem rather than an isolated injector issue.
- Check the injector solenoid circuit for open circuit, short to ground, or short to battery voltage using a multimeter per the wiring diagram.
- Inspect the engine harness routing for chafe points, pinched sections, or heat damage that could cause an intermittent or permanent short.
- If wiring and harness check out, test or swap the injector to isolate a faulty solenoid or injector from a wiring fault.
- Rule out a mechanical problem in the cylinder if electrical checks come back clean.
How the code clears
No separate clearing step is listed for this code. Once the underlying wiring, connector, solenoid, or injector fault is repaired, the ECM should stop logging the code as it continues to monitor the injector circuit during normal operation. Clear logged codes with your diagnostic tool after the repair and verify the code does not return under normal operation.
Affected models and serial ranges
211 appears in our records across 4 CAT Engine models. Match your machine by model and serial number.
| Model | Serial ranges |
|---|---|
| C10 | Serial range not listed in source records |
| C12 | Serial range not listed in source records |
| C15 | Serial range not listed in source records |
| C16 | Serial range not listed in source records |
Frequently asked questions
What does CAT code 211 mean?
It means the ECM detected an open circuit or a short circuit while trying to operate the cylinder #2 injector. This causes engine misfires and low power.
Which CAT engines use fault code 211?
This code applies to the C10, C12, C15, and C16 engine models.
Can one bad wire affect more than cylinder #2?
Yes. Injectors on these engines share a common wire between cylinders. If the fault is in that shared wire, two cylinders can be affected at the same time, not just cylinder #2.
Will the engine keep running with this code active?
The ECM keeps trying to operate the injector after logging the code, but the injector may not fire correctly while the fault exists, so expect misfires and reduced power rather than a complete shutdown.
What's the most common cause of this code?
Damaged or corroded wiring and connectors in the injector circuit are the most frequently listed cause, followed by harness problems, faulty solenoids, and injector failure.
Is code 211 caused by a bad injector or bad wiring?
It can be either. Possible causes range from wiring damage, harness shorts, and shorts to ground, to a faulty injector solenoid, a bad injector, or even a faulty ECM. Testing the circuit is the only way to know which.
Do I need to reset the ECM after fixing this fault?
No separate clearing procedure is listed. Repair the underlying cause, clear the logged code with your diagnostic tool, and confirm it does not come back during operation.