Fail-Safe System; Pre-Programmed Value For Fail-Safe System - BOMBARDIER Johnson 90 Service Manual

ENGINE CONTROL SYSTEM
FAIL-SAFE SYSTEM
FAIL-SAFE SYSTEM
The fail-safe system is closely related to the self-diagnostic system. When an abnormality occurs in a
sensor signal, the ECM ignores the out-of-range signal and assumes a pre-programmed value for the
failed sensors. This allows the engine to continue running under the fail-safe condition.
Pre-Programmed Value For Fail-Safe System
FAILED ITEM PRE-PROGRAMMED VALUE
MAP sensor 1 • 319 - 475 mmHg / (Corresponds to approx. 750 - 4000 rpm) (NOTE 1)
CKP sensor Based on signals from CMP sensor:
• lgnition timing fixed at BTDC 5º
• Normal sequential fuel injection
CMP sensor Based on signals from CKP sensor:
(a) Failed while engine running
• lgnition timing fixed at BTDC 5º
• Normal sequential fuel injection
(b) Failed prior to engine start
• lgnition timing fixed at BTDC 5º
• 1 simultaneous injection for all cylinders per 2 crankshaft rotations
Cylinder temp. sensor 60 ºC (140 ºF)
IAT sensor 45 ºC (113 ºF)
Exhaust manifold temp. sensor 60 ºC (140 ºF)
NOTE:
There is no backup system for the ECM itself. The engine wi/1 stop if it has failed.
NOTE 1:
This value wi/1 change according to the current engine speed.
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