Maintenance Manual for J2 Sedan
Electronic Control System
of Engine
206
Section IV Trouble Diagnosis Procedures for Engine Control System
I.
Diagnosis with DTC
1. Instruction
1) The following Repair can be carried out only after the current stable trouble has been identified,
otherwise the diagnosis will be wrong.
2) The "multi-meter" hereinafter refers to the digital multi-meter and it is not permitted to use the
analog multi-meter to check the electric control system circuits.
3) When carrying out the Repair for the vehicle with the anti-theft system, if the requirement of
replacing the ECM is included in the "Next Steps" column, it is necessary to program the ECM
after replacement.
4) If the DTC points to low voltage of a specific circuit, it indicates that the circuit is likely to have
short circuit with ground or open circuit; if the DTC points to high voltage of a specific circuit, it
indicates that the circuit is likely to have short circuit with power circuit; if the DTC points to a
circuit trouble, it indicates that the circuit is likely to have broken circuit or a variety of line
troubles.
2. Diagnosis Help
1) If the DTC can not be erased, it means the trouble is stable; in case of the sporadic trouble, it is
necessary to check whether the connector of wire harness is loosened.
2) The check has been accomplished with steps above and nothing unusual has been found.
3) Effects of the maintenance of vehicle, cylinder pressure and mechanical ignition timing etc. on the
system should not be neglected during the inspection and repairing.
4) Replace the ECM to carry out the test.
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If the DTC can be cleared at this time, it means the trouble site is at ECM; if the DTC still can not
be erased at this point, then remount the original ECM and repeat the procedures again to carry out
the Repair.
