CM870 and ISX Engines – FAULT CODE 341

Unswitched Battery Supply Circuit


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

Engine control module (ECM) data lost.

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

Unswitched Battery Supply Circuit

Circuit Description

The ECM receives constant voltage at the 4-pin power connector from the batteries through the unswitched battery wires that are connected directly to the positive (+) battery post. The ECM receives switched battery input through the vehicle keyswitch wire, in the 50-pin OEM ECM connector, when the vehicle keyswitch is turned on. Pins 2 and 3 are optional circuits the OEM may not use. Refer to the OEM wiring diagram for detailed information on these circuits.

Component Location

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

Refer to Troubleshooting Fault Code t05-341

Last Modified:  01-Sep-2010