CAT Engine 27413 Fault Code: Atmospheric Pressure Sensor: Calibration Required
Also called Atmospheric Pressure Sensor : Calibration Required
Atmospheric Pressure Sensor: Calibration Required · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
Code 27413 (SPN 108, FMI 13) means the CAT ECM could not automatically calibrate the atmospheric pressure sensor signal because its voltage was too far from the expected reference voltage. It applies to C13, C15, and C18 engines and points to a sensor, connector, wiring, or blocked sensor port problem rather than an actual pressure event.
Medium severity. This is not an immediate stop-engine code, but the atmospheric pressure reading feeds into engine performance and emissions calculations, so it should be diagnosed within the shift rather than ignored long term.
What does CAT Engine error code 27413 mean?
Code 27413 is set when the Electronic Control Module (ECM) cannot complete automatic calibration of the atmospheric pressure sensor. During each key on event lasting at least 2 seconds, the ECM checks the sensor's signal voltage against an internal reference voltage. If the two are close, the ECM adjusts the signal internally so the reported pressure value is accurate, a process CAT calls automatic sensor calibration.
If the signal voltage is not close enough to the reference voltage, the ECM cannot make that internal adjustment. Instead of guessing at a pressure value, it sets fault code 27413 to flag that the sensor signal cannot be trusted for calibration.
The atmospheric pressure sensor helps the ECM correct fueling, boost, and emissions-related calculations for altitude and ambient conditions. When this sensor's signal is unreliable, the engine may still run, but certain compensations may not be as accurate until the fault is resolved.
What triggers a CAT Engine 27413 code?
The ECM evaluates the atmospheric pressure sensor signal voltage during each key on event of at least 2 seconds. It compares that signal voltage to an internal reference voltage. If the signal voltage is not close enough to the reference voltage, the ECM cannot perform automatic sensor calibration and sets code 27413.
Common causes of 27413
- Faulty atmospheric pressure sensor (bad sensor)
- Sensor port blocked by debris
- Damaged connectors and/or wiring at the sensor circuit
- General problem with the wiring harness
- Bad or corroded connector in the sensor circuit
How to troubleshoot CAT Engine 27413: first checks
- Inspect the atmospheric pressure sensor's connector for corrosion, moisture, or loose pins.
- Check the sensor port for any blockage from dirt, debris, or contamination that could affect the pressure reading.
- Visually trace the wiring harness between the ECM and the sensor for chafing, pinches, or damage.
- Confirm the sensor itself is seated properly and not physically damaged.
- Cycle the key off and on to see if the fault clears after a fresh calibration attempt, since the ECM re-evaluates the signal on each key on event of at least 2 seconds.
How the code clears
No separate clearing step is listed. Since the ECM re-checks the sensor signal during every key on event of at least 2 seconds, once the underlying wiring, connector, or sensor problem is corrected, the ECM should be able to complete automatic calibration on a subsequent key cycle and the code should clear on its own. If it does not clear after repairs, the sensor itself likely needs replacement.
Affected models and serial ranges
27413 appears in our records across 3 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 |
Frequently asked questions
What does CAT fault code 27413 mean?
It means the ECM tried to automatically calibrate the atmospheric pressure sensor's signal voltage during a key on event and found the voltage too far from the expected reference voltage to complete that calibration.
Is code 27413 dangerous to keep driving with?
It is not an emergency shutdown code, but the atmospheric pressure reading affects engine compensation calculations. It's best to diagnose it within the same shift rather than let it sit indefinitely.
Which engines can set SPN 108 FMI 13?
This code applies to CAT C13, C15, and C18 engines.
What usually causes this code?
The most common causes are a faulty atmospheric pressure sensor, a sensor port blocked by debris, or damaged connectors and wiring in that circuit.
Will the code clear itself after I fix the wiring or sensor?
Likely yes. The ECM re-evaluates the sensor signal on every key on event of at least 2 seconds, so once the wiring, connector, or sensor issue is fixed, the ECM should complete calibration and the code should clear on its own.
Do I need a scan tool to diagnose 27413?
A scan tool helps confirm the code and check for related active faults, but much of the diagnosis is physical: inspecting the sensor port, connector, and harness for damage or blockage.
Can a blocked sensor port really cause this fault?
Yes. If debris blocks the sensor port, the sensor cannot read atmospheric pressure accurately, which throws off the signal voltage enough that the ECM cannot calibrate it against the reference voltage.