CAT Engine 26111 Fault Code: Engine Timing Offset fault
Also called Engine Timing Calibration : Other Failure Mode, Engine Timing Offset Fault, Engine Timing Sensor : Other Failure Mode
Engine Timing Offset fault · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
CAT code 26111 (SPN 637 / FMI 11) fires when the ECM sees the primary and secondary engine speed/timing sensor signals disagree by more than 8 degrees of crankshaft rotation while the engine has been running for more than 5 seconds. It points to a timing signal mismatch between the crankshaft and camshaft sensors, not necessarily a failed part. Depending on the engine model, this can range from a code that logs with no drivability change to one that sets timing calibration to zero degrees and causes misfire, low power, or white exhaust smoke.
High severity. This code by itself does not stop the engine if only one sensor signal is lost, the engine keeps running. But if both sensors lose signal, fuel injection is terminated and the engine shuts down. On some engine variants the ECM resets timing calibration to zero degrees, which can cause misfire, power loss, and visible white smoke, so it should be diagnosed promptly rather than ignored.
What does CAT Engine error code 26111 mean?
Code 26111 relates to the engine's crankshaft and camshaft speed/timing sensors, sometimes called the primary and secondary speed/timing sensors. The primary sensor reads the crankshaft timing ring near the flywheel housing and is used mainly to determine engine rpm. The secondary sensor reads a camshaft-related pattern (location varies by engine, for example under the high-pressure fuel pump on the C4.4 or at the rear of the block on the C7.1) and is used mainly to establish the engine's firing position, especially at startup.
During normal running, the ECM uses the secondary sensor signal to figure out which stroke the engine is on, then hands off to the primary sensor to track speed and angular position. Code 26111 sets when these two signals disagree by more than 8 degrees of crankshaft rotation after the engine has run for more than 5 seconds, telling the ECM the two references no longer agree on where the crankshaft and camshaft actually are.
On some engine families this fault is purely diagnostic and does not get logged. On others, the ECM responds by setting the engine's timing calibration to zero degrees, which can cause misfire, low power or reduced speed, and increased exhaust emissions including white smoke. The practical effect depends on which sensor signal, if any, is lost: the engine keeps running on a single good sensor signal, but loses fuel injection and shuts down if both signals are lost.
What triggers a CAT Engine 26111 code?
The ECM sets this code when the primary and secondary speed/timing sensor outputs differ by more than 8 degrees of crankshaft rotation, the engine has been running for more than 5 seconds, diagnostic code 190-8 is not active, and 678 diagnostic codes (or on some engines, 3512 or 3483 codes) are not active. A warning light comes on if equipped. On some engine variants this code is not logged; on others it is logged and timing calibration is set to zero degrees.
Common causes of 26111
- Damaged, corroded, or loose connectors and wiring between the ECM and either speed/timing sensor
- A general problem within the wiring harness itself
- A faulty or damaged primary or secondary speed/timing sensor, or damaged sensor assembly components
- A damaged or faulty crankshaft or camshaft timing ring, or a faulty camshaft
- Incorrect sensor resistance or an electrical problem with the speed/timing sensor circuit
- Incorrect installation of the sensors or reversed wiring polarity to one of the sensors
- A problem with the gear train affecting the relationship between camshaft and crankshaft position
- On some models, a faulty switch or a need to replace the ECM
How to troubleshoot CAT Engine 26111: first checks
- Inspect the wiring and connectors at both the primary and secondary speed/timing sensors for corrosion, damage, looseness, or reversed polarity
- Check sensor resistance against the manufacturer's specification if a meter and specs are available
- Look for stored codes 190-8, 678, 3512, or 3483, since their presence affects whether 26111 will set
- Verify sensor installation, some sensor sets are magnetic and not interchangeable, do not swap their positions on engines where that applies
- Inspect the timing ring and gear train condition where accessible, watching for physical damage
- On engines where sensors are interchangeable (per the applicable service information for that engine), swap the primary and secondary sensors to help isolate which one is faulty
How the code clears
No separate clearing step is listed beyond correcting the underlying cause. On some engines this code is not logged at all, so it will simply stop reporting once the sensor signals agree within tolerance. On engines where the ECM logs the code and sets timing calibration to zero degrees, repairing the wiring, connector, or sensor issue and confirming normal sensor agreement should allow the engine to return to normal timing operation. If sensors are replaced as a set on the applicable engine, a separate timing calibration is not necessary. If the ECM is replaced, ECM parameters and timing calibration can be transferred to the new ECM without needing recalibration.
Affected models and serial ranges
26111 appears in our records across 6 CAT Engine models. Match your machine by model and serial number.
| Model | Serial ranges |
|---|---|
| C11 | Serial range not listed in source records |
| 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 fault code 26111 mean?
It means the ECM detected that the primary and secondary engine speed/timing sensors disagree on crankshaft position by more than 8 degrees, after the engine had been running more than 5 seconds. This points to a timing signal mismatch, which can come from wiring, a sensor, or physical timing ring/gear issues.
Will code 26111 shut down my engine?
Not automatically. The engine keeps running if only one sensor's signal is present. It only stops if both the primary and secondary sensor signals are lost at the same time, since that stops fuel injection entirely.
Can I keep operating with this code active?
On some engine variants the code is informational and not even logged. On others the ECM resets timing calibration to zero degrees, which can cause misfire, low power, reduced speed, or white exhaust smoke. Given the risk of drivability and emissions problems, it is best to get it diagnosed rather than run indefinitely.
Can I swap the primary and secondary timing sensors to test them?
It depends on the engine. Some engine families use interchangeable sensors, so swapping them can help isolate a faulty unit. Others use non-interchangeable magnetic sensors that should never have their positions swapped and should be replaced as a set instead. Check the applicable service information for your specific engine before swapping anything.
Do I need a timing calibration after replacing the sensors?
On engines where the sensors are replaced as a set, no separate timing calibration is necessary. If the ECM itself is replaced, its parameters and timing calibration can be carried over to the new ECM, so recalibration is not required there either.
What other codes affect whether 26111 sets?
The ECM checks that diagnostic code 190-8 is not active, and that 678 diagnostic codes (or on some engines, 3512 or 3483) are not active, before it will set 26111.
Which CAT engines use this code?
This code applies to the C11, C13, C15, C18, C27, and C32 engine families, with sensor locations and interchangeability differing by specific engine model.