W T E C I I I E L E C T R O N I C C O N T R O L S T R O U B L E S H O O T I N G M A N U A L
APPENDIX H INPUT/OUTPUT FUNCTIONS
These schematics show the intended use of the specified controls features which
have been validated in the configuration shown. Any miswiring or use of these
features which differs from that shown could result in damage to equipment or
property, personal injury, or loss of life. ALLISON TRANSMISSION IS NOT
LIABLE FOR THE CONSEQUENCES ASSOCIATED WITH MISWIRING
OR UNINTENDED USE OF THESE FEATURES.
H. ENGINE BRAKE/PRESELECT REQUEST AND ENGINE BRAKE ENABLE
(EXHAUST BRAKE OPTIONAL)
USES: Used with engine brakes controlled by electronic engines to signal the ECU that the brake is active and to
provide increased braking by preselecting a lower range. Also prevents engagement of engine brake with
throttle > 0 or lockup OFF.
VARIABLES TO SPECIFY:
Preselect range. Standard value is second range.
Figure H4. Engine Brake/Preselect Request and Engine Brake Enable (Exhaust Brake Optional)