CAT 3406E (Prefix 1MM or 2WS) Fault Code: 00 PID: SPN: 171 FMI: 4 Ambient Air Temperature voltage low
The Engine Control Module (ECM) detects the following conditions:
•The signal voltage from the ambient air temperature sensor is less than 0.2 VDC for more than eight seconds.
•The “Allow Idle Shutdown Override” parameter is programmed to “Outside Temperature Based” or “J1587 Outside Temperature Based”.
•The ECM has been powered for at least two seconds.
Probable Causes:
1) ECM Connection/Harness
2) If code 232-3 or 232-4 (5 Volt Supply voltage codes) are active, troubleshoot those instead
3) Temperature sensor failure
4) Temperature sensor harness
5) ECM Failure
