Operation and maintenance manual

Electronic Controlled Fuel System QSB4.5 and QSB6.7
Page 1-12 Section 1 - Operating Instructions
The fault code will flash in the following sequence:
• First, a WARNING (yellow) lamp will flash.
• Then there will be a short 1- or 2-second pause, after
which the number of the recorded fault code will flash
in STOP (red) lamp. There will be a 1- or 2-second
pause between each number.
• When the number has finished flashing in red, a yellow
lamp will appear again. The three-digit code will repeat
in the same sequence.
The lights flash each fault code out two times before
advancing to the next code. To skip to the next fault code
sooner, move the idle speed adjust switch, if equipped
momentarily to the "(+)" position. The previous fault code
can be accessed by momentarily moving the idle speed
adjust switch, if equipped to the "(-)" position. If only one
active fault is recorded, the control system will
continuously display the same fault code, even when
either the "(+)" or "(-)" switch is depressed.
The explanation and correction of the fault codes are
explained in Section TF in the ISB, ISBe2, ISBe3, ISBe4,
QSB4.5, QSB5.9, QSB6.7, ISC, QSC8.3, ISL, ISLe3,
ISLe4, and QSL9 CM850 Electronic Control System
Troubleshooting and Repair Manual, Bulletin Number
4021416.
When not using the diagnostic system, turn off the
diagnostic switch, or remove the shorting plug. If the
diagnostic switch is left on or the shorting plug in, the
ECM will not log some faults.