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Electronic Control System ISM and QSM11 Engines – FAULT CODE 388

Engine Brake Supply Circuit


Overview

CODE REASON EFFECT
Fault Code: 388
PID: S079
SPN: 1072
FMI: 11
LAMP: Yellow
SRT: 

Less than 6 VDC detected at the engine brake circuit 1 when on indicates an excessive current draw from the electronic control module (ECM) or faulty ECM output circuit.

Engine brake 1 can not be activated.
Engine Brake 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 conditions.

Component Location

Refer to an OEM diagram for the location of the engine brake.

Shop Talk

A possible cause for this fault code is an ECM engine brake driver 1 short to ground.

Refer to Troubleshooting Fault Code t05-388

Last Modified:  02-Sep-2010
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