Electronic Control System Signature, ISX and QSX15 Engines – FAULT CODE 341

Unswitched Battery Supply Circuit


Fault Code: 341
PID: S253
SPN: 630
FMI: 2/2
LAMP: Yellow

Severe loss of data from the ECM.

Possibly no noticeable performance effects, or engine dying, or difficulty in starting the engine. Fault information, trip information, and maintenance monitor data can be inaccurate.

Unswitched Battery Supply

Circuit Description

The ECM receives constant voltage from the batteries through the unswitched battery wires that are connected directly to the positive (+) battery post. There are two in-line 15-amp fuses in the unswitched battery wires to protect the engine harness from overheating. The ECM receives switched battery input through the vehicle keyswitch wire when the vehicle keyswitch is turned on. The battery return wires are connected directly to the negative (-)
battery post.

Component Location

The ECM is connected to the battery by the OEM harness. This direct link provides a constant power supply for the ECM. The location of the battery will vary with the OEM. Use the OEM troubleshooting and repair manual.

Refer to Troubleshooting Fault Code t05-341.

Last Modified:  26-Oct-2010