GENERAL – How to Use Troubleshooting/Inspection Service Points00-10
HOW TO USE THE INSPECTION PROCEDURES
The causes of a high frequency of problems occurring in electronic circuitry are generally the connectors,
components, the ECU and the harnesses between connectors, in that order. These inspection procedures
follow this order, and they first try to discover a problem with a connector or a defective component.
Indicator does not turn on or off even if control
mode switch is pressed.
Indicator switch should not be illuminated is
illuminated.Probable cause
OK
OK
OK
Measure at switch connector A-44
Disconnect the connector, and measure at the harness
side.
Voltage between terminal 6 – earth and terminal 8 –
earth
OK:Approx. 5V
OK
NG
Check the following connector. A-44
Repair
OK
Check trouble symptom.
Replace the ECS-ECU.
In the above cases, the ECS switch circuit is defective or the indicator
circuit is defective.
CHECKING PROCEDURE 4
2. Indicates inspection carried out using the
MUT-II.
Indicates the operation and inspection proce-
dures.
Indicates the OK judgement conditions.
3. Detailed inspection procedures (methods)
such as component inspection and circuit
inspection are listed on a separate page, and
are given here for reference.
5. Inspect the contact condition at each connector terminal.
(Refer to Connector Inspection Service Points.)
The connector position can be located in the wiring diagram in the
electrical wiring manual by means of this symbol.
Caution
After carrying out connector inspection, always be sure to
reconnect the connector as it was before.
6. Confirm that there are trouble symptoms. If trouble symptoms have
disappeared, the connector may have been inserted incorrectly and the
trouble symptom may have disappeared during inspection.
If it seems that trouble symptoms still remain, proceed to the next page of
instructions.
7. If trouble symptoms still remain up to this stage, there is a possibility that there is an
open or short circuit in the harness between the connectors, so check the harness.
Alternatively, the cause may be a defective ECU, so try replacing the ECU and check
if the trouble symptom disappears.
NGECU switch component inspection (Refer to P.3-44.)
NG
1. Comments on the diagnosis code or trouble
symptom above.
MUT-II Data list
17 Control mode selection switch
OK:Voltage changes between approx. 0V → approx.
2.5V → approx. 5V when the switch is operated.
4. Indicates voltage and resistance to be measured at a particular
connector.
(Refer to Connector Measurement Service Points.)
The connector position can be located in the wiring diagram in the
electrical wiring manual by means of this symbol.
Indicates operation and inspection procedures, inspection terminals
and inspection conditions.
Indicates the OK judgement conditions.
HARNESS INSPECTION
Check for an open or short circuit in the harness between the terminals which were defective according
to the connector measurements. Carry out this inspection while referring to the electrical wiring manual.
Here, “Check harness between power supply and terminal xx” also includes checking for blown fuses.
For inspection service points when there is a blown fuse, refer to “Inspection Service Points for a Blown
Fuse.”
MEASURES TO TAKE AFTER REPLACING THE ECU
If the trouble symptoms have not disappeared even after replacing the ECU, repeat the inspection procedure
from the beginning.
