Electronic Control System Signature, ISX and QSX15 Engines – FAULT CODE 442

Unswitched Battery Supply Circuit


Fault Code: 442
PID: P168
SPN: 168
FMI: 0/16
LAMP: Yellow

Battery voltage above normal operating level.

None on performance.

Unswitched Battery Supply Circuit

Circuit Description

The electronic control module (ECM) receives unswitched battery input through the OEM harness. There are two in-line 15-amp fuses in the unswitched battery wire to protect the OEM harness from overheating. 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. Use the OEM troubleshooting and repair manual for battery location.

Shop Talk

Disconnect all aftermarket devices from the battery supply circuit. Make sure the proper-size fuses are being used (15-amp fuses).

Refer to Troubleshooting Fault Code t05-442.

Last Modified:  26-Oct-2010