Electronic Control System Signature, ISX and QSX15 Engines – FAULT CODE 393

Engine Brake Supply Circuit


Overview

CODE REASON EFFECT
Fault Code: 393
PID: S082
SPN: 1112
FMI: 11/11
LAMP: Yellow
SRT: 

Less than (+) 6-VDC detected at engine brake circuit 3 when on; this indicates an excessive current draw from the ECM or a faulty ECM output circuit.

The engine brakes can
not be activated on cylinders Number 4, 5, and 6 (for six-level engine brake harness), or engine brakes can
not be activated on cylinders Number 1, 4, 5, and 6 (for three-level engine brake harness).

Engine Brake Relay Supply Circuit
SMALL | MEDIUM | LARGE

Circuit Description

The ECM enables the engine brake by sending a signal directly to the engine brakes. The ECM will
only enable the engine brakes under certain operating conditions.

Component Location

The engine brakes are located under the valve cover.

Shop Talk

Possible cause for this fault code:

  • ECM engine brake circuit 3 has a short circuit to ground.

Refer to Troubleshooting Fault Code t05-393.

Last Modified:  26-Oct-2010