Cummins ISB4.5 CM2150 Fault Code: 2412 PID: 26 SPN: 1639 FMI: 2 Fan Speed – Data Erratic, Intermittent, or Incorrect.

Circuit Description
The fan speed sensor is a variable resistance speed sensor. It consists of a coil of wire and an iron core. The target on the fan hub shaft is a ground flat in the center of the shaft. The engine control module (ECM) interprets this signal and converts it to a fan speed reading.

Component Location
The fan speed sensor is located in the fan hub assembly. Refer to the original equipment manufacturer (OEM) troubleshooting and repair manual.

Conditions for Running the Diagnostics
This diagnostic runs continuously when the engine is running.

Conditions for Setting the Fault Codes
The ECM detects that the fan speed signal has been lost.

Action Taken When the Fault Code is Active
-The ECM illuminates the amber CHECK ENGINE light immediately when the diagnostic runs and fails.
-The fan will only be in the ON or OFF position

Conditions for Clearing the Fault Code
The ECM will turn off the amber CHECK ENGINE light immediately after the diagnostic runs and passes.

Shop Talk
Verify the ECM calibration is correct. Check the calibration revision history found on QuickServe® Online for applicable fixes to the calibration stored in the ECM. If necessary, recalibrate the ECM
The fan speed sensor is installed by the OEM. This fault code is triggered when the fan speed signal is reading 0 when the engine is running. This indicates a malfunctioning fan speed sensor or a malfunction in the OEM wiring harness.