Mitsubishi Lancer Evolution IV, Workshop Manual

Page: 355 / 391

CHASSIS ELECTRICAL –
Ignition Switch and Immobilizer System
54-15
Code No. 21 Communication system between MUT- II and
engine-ECU
Probable cause
After the ignition switch is turned to the ON position, the confirmation code is not
received from the engine-ECU within the allowable time, or an abnormal code is received.
D
Malfunction of harness or connector
D
Malfunction of the engine-ECU
D
Malfunction of the immobilizer-ECU
Is diagnosis code No. 54 being gener-
ated by the engine-ECU?
NO
Check the engine-ECU power source
and the earth circuit.
(Refer to GROUP 13A – Troubleshoot-
ing.)
YES
Check the following connectors.
B-100, B-65, B-61
NG
Repair
OK
Check trouble symptoms.
NG
Check the harness wire between
engine-ECU and immobilizer-ECU.
NG
Repair
OK
Check trouble symptoms.
NG
Replace the immobilizer-ECU.
Check trouble symptoms.
NG
Replace the engine-ECU.
Code No. 31 EEPROM abnormality inside immobilizer-
ECU Probable cause
No data has been written to the EEPROM inside the immobilizer-ECU.
D
Malfunction of the immobilizer-ECU
Check trouble symptoms.
NG
Replace the immobilizer-ECU.