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ENGINE MANAGEMENT MODULE (EMM)
INTERNAL EMM FUNCTIONS
4
INTERNAL EMM
FUNCTIONS
Start Assist Circuit (SAC)
When the ignition key is ON, the EMM Start Assist
Circuit (SAC) boost s battery volt age (12 V) to
30 V on the system (55 V) circuit.
If the SAC circuit current exceeds 2 Amps, or if the
SAC voltage is less than 20 V, the EMM:
ROM Verification
The EMM perfo rms a se lf-test of programming
every time it is tu rned ON. Service code 15 ind i-
cates a programming (software) issue. Re pro-
gram the EMM with the correct software program
to correct the problem.
Idle Controller
The idle controller reacts to engine operating con-
ditions. Fu el an d ign ition timings are a ltered to
maintain a specific RPM when e ngine is cold or
warm. The contro ller is inactive when TPS is
advanced from idle position.
RPM Limiter
This featu re of EMM pr ogramming prevents
engine d amage due to excessive RPM. At 625 0
RPM, fuel and ignition to the cylinders is shut off.
Normal ope ration resumes when engin e RPM
returns to the specified range.
Neutral RPM Limiter
This feature prevents engine dama ge due to
excessive RPM if accelerated in NEUTRAL. Neu-
tral engine speed is limited to 1100 RPM.
Engine Monitor and Warning
Systems
Refer to ENGINE MONITOR SYSTEM on p. 62.
Refer to S.A.F.E. WARNING SYSTEM on p. 63.
Refer to SHUTDOWN MODE on p. 63.
Fault Code Creation and Storage
Refer to the EMM Service Code Chart at the
back o f this ma nual for a complete list of all
engine fault codes.
Stores service code 77
EMM LED 1: ON (Running)
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