CAT 3406E (Prefix 1MM or 2WS) Fault Code: 26 PID: SPN: 108 FMI: 4 Atmospheric Pressure voltage low

The Engine Control Module (ECM) detects the following conditions:

•The signal voltage from the atmospheric pressure sensor is less than 0.2 VDC for more than 30 seconds.
•The ECM has been powered for at least two seconds.
•The engine is not running or the engine has been running for more than ten seconds.

Probable Causes:

1) ECM Connection/Harness
2) Crankcase breather plugged
3) Pressure sensor
4) Pressure sensor harness
5) ECM Failure