Electronic Control System Signature, ISX and QSX15 Engines – FAULT CODE 387

Throttle Voltage Supply


Fault Code: 387
PID: P221
SPN: 1043
FMI: 3/3
LAMP: Yellow

High voltage detected on the ECM voltage supply line to the throttle(s)
(VTP supply).

Engine will only idle.

Throttle Sensor Supply Voltage Circuit

Circuit Description

The ECM supplies the throttle and remote throttle with (+) 5 VDC. If the supply line to the throttles is damaged, the throttle will not
work correctly.

Component Location

The throttle pedal is located in the cab. Use the OEM troubleshooting and repair manual for the location of the remote throttle.

Shop Talk

High voltage on the (+) 5-VDC supply line will be caused by a short circuit to battery of the supply line or a short circuit between an actuator and the supply line.

Refer to Troubleshooting Fault Code t05-387.

Last Modified:  26-Oct-2010