CAT 2211 Fault Code: Engine Timing Sensor : Other Failure Mode
Also called Primary to Secondary Engine Speed Signal Calibration
Engine Timing Sensor : Other Failure Mode · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
CAT 2211 sets when the ECM finds the primary and secondary engine speed/timing sensor signals off by more than 3 degrees after a timing calibration has completed and battery voltage is above 9 V. It affects C13 and C15 engines and points to a camshaft sensor, wiring, or ECM problem rather than an immediate shutdown in most cases.
Medium severity. The engine can keep running on a single good sensor signal with no noticeable performance change. It will only shut down or fail to start if both sensor signals are lost at the same time, so 2211 by itself is not usually an emergency, but it should be diagnosed before a second sensor fails.
What does CAT error code 2211 mean?
CAT 2211 is set by the ECM when it compares the primary and secondary engine speed/timing sensor signals and finds them disagreeing by more than 3 degrees, after a timing calibration has already completed successfully and with battery voltage above 9 V.
The engine uses two magnetic speed/timing sensors that read a unique pattern off the camshaft gear. The ECM uses the pulse pattern from these sensors to figure out crankshaft position and rpm, then times each injector's firing accordingly. Under normal operation the secondary sensor establishes timing at startup (locating the No. 1 cylinder at top of the compression stroke), and once timing is established the primary sensor takes over for engine speed.
Losing one sensor's signal while running causes no noticeable performance change since the ECM can still operate on the remaining sensor. Losing both sensors while running stops fuel injection and shuts the engine down. Losing both sensors at startup will prevent the engine from starting at all. 2211 itself is about the two signals disagreeing, not necessarily about losing a signal entirely.
What triggers a CAT 2211 code?
The ECM sets this code when: the primary and secondary speed/timing sensor readings differ by more than 3 degrees, a timing calibration has been successfully completed, and battery voltage is above 9 V.
Common causes of 2211
- ECM connection problem (corroded, loose, or damaged connector at the ECM)
- Engine speed/timing sensor failure, or a sensor installed improperly (including swapping the primary and secondary sensor positions, which is not allowed since they are not interchangeable)
- Engine speed/timing sensor wiring harness fault (chafed, corroded, or damaged wiring between sensor and ECM)
- ECM failure
How to troubleshoot CAT 2211: first checks
- Inspect the ECM connectors for corrosion, loose pins, or damaged terminals before touching the sensors.
- Confirm both camshaft speed/timing sensors are installed in their correct, original positions. The two sensors are not interchangeable and must never be swapped.
- Trace and inspect the engine speed/timing sensor wiring harness end to end for chafing, corrosion, pinches, or loose connectors.
- Check battery voltage is solid and above 9 V so you know the fault isn't being triggered or masked by a weak charging system.
- If a sensor is suspect, plan to replace both engine speed/timing sensors as a matched pair, never just one, per Cat's instructions.
How the code clears
No separate clearing step is listed beyond fixing the underlying cause. If the sensors are replaced, a timing calibration is not necessary. A timing calibration is only required after replacing an ECM that will not communicate. Once the wiring, connector, sensor, or ECM issue is corrected, the code should clear on its own after the ECM re-evaluates the sensor signals.
Affected models and serial ranges
2211 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 2211 mean?
It means the ECM found the primary and secondary engine speed/timing sensors disagreeing by more than 3 degrees after a timing calibration completed successfully, with battery voltage above 9 V. It's a calibration mismatch between the two camshaft timing sensors, not necessarily a total signal loss.
Can I keep driving or running the engine with code 2211 active?
Often yes, in the short term, since the engine will run normally on one good sensor with no noticeable performance change. But you're then one sensor failure away from a shutdown (if running) or a no-start (if the engine is off), so get it diagnosed promptly.
Do I need to replace one sensor or both?
Both. Cat specifies that if either engine speed/timing sensor is replaced, both sensors must be replaced together as a matched pair. Do not mix an old sensor with a new one.
Do I need to recalibrate timing after replacing the sensors?
No. If the sensors are replaced, a timing calibration is not necessary. Timing calibration is only required after replacing an ECM that will not communicate.
Can the primary and secondary sensors be swapped or used interchangeably?
No. The two sensors are not interchangeable and their positions must never be switched. Doing so can itself cause a timing mismatch and trigger this code.
What happens if both timing sensors fail at once?
If the engine is running and both sensor signals are lost, the ECM will terminate fuel injection and shut the engine down. If both signals are lost before startup, the engine will not start at all.
Which engines does CAT 2211 apply to?
It applies to C13 and C15 engines, tied to SPN 637 / FMI 11 for the primary-to-secondary engine speed signal calibration fault.