3-30 ENGINE CONTROL 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
NOTE:
There is no back-up system for the ECM itself. The engine will stop if it has failed.
NOTE 1:
This value will change according to the current engine speed.
MAP sensor 1 • 319 – 475 mmHg (Correspond to approx. 750 – 4000 r/min) [NOTE1]
CKP sensor Based on signals from CMP sensor:
• Ignition timing fixed at BTDC 5°
• Normal sequential fuel injection
CMP sensor Based on signals from CKP sensor:
(a) Failed while engine running
• Ignition timing fixed at BTDC 5°
• Normal sequential fuel injection
(b) Failed prior to engine start
• Ignition timing fixed at BTDC 5°
• 1 simultaneous injection for all cylinders per 2 crankshaft rotations
Cylinder temp. sensor 60 °C (140 °F)
IAT sensor 45 °C (113 °F)
Exhaust manifold
60 °C (140 °F)
temp. sensor
FAILED ITEM PRE-PROGRAMMED VALUE
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