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ENGINE MANAGEMENT MODULE (EMM)
INTERNAL EMM FUNCTIONS
INTERNAL EMM
FUNCTIONS
Start Assist Circuit (SAC)
When the ignition key is ON, the EMM Start Assist
Circuit (SAC) boosts battery voltage (12 V) to
30 V on the system (55 V) circuit.
ROM Verification
The EMM performs a self-test of programming
every time it is turned ON. Service code 15 indi-
cates a programming (software) issue. Repro-
gram the EMM with the correct software program
to correct the problem.
Idle Controller
The idle controller reacts to engine operating con-
ditions. Fuel and ignition timings are altered to
maintain a specific RPM when engine is cold or
warm. The controller is inactive when TPS is
advanced from idle position.
RPM Limiter
This feature of EMM programming prevents
engine damage due to excessive RPM. At 6250
RPM, fuel and ignition to the cylinders is shut off.
Normal engine operation resumes when engine
RPM returns to the specified range.
98
Shift Interrupt
The shift interrupt function of EMM programming
shuts off fuel and spark to three cylinders for
approximately one second to reduce drivetrain
loads and ease shifting, then immediately restores
normal engine operation. The shift interrupt switch
must be released to its normal open position
before the shift interrupt function can be activated
again. This function is not operational above 2500
RPM.
The EMM provides voltage to the shift interrupt
switch circuit. If the switch or circuit fails, the EMM
stores a service code.
Engine Monitor and Warning
Systems
Refer to ENGINE MONITORING SYSTEM on
p. 99.
Refer to S.A.F.E. WARNING SYSTEM on p. 100.
Refer to SHUTDOWN MODE on p. 100.
Fault Code Creation and Storage
Refer to the EMM Service Code Chart at the
back of this manual for a complete list of all
engine fault codes.
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Troubleshooting
