Diagnosis Item
15: Diagnose when the M.U.T.-III cannot receive the data sent by steering wheel sensor.
caution |
When servicing a CAN bus line,
earth yourself by touching a metal object such as an unpainted water pipe. If you fail to do,
a component connected to the CAN bus line may be broken.
|
FUNCTION
The diagnostic result demonstrates that "the M.U.T.-III cannot receive the sent data from
the steering wheel sensor" when the M.U.T.-III checks the periodically sent data from each ECU
and cannot receive the steering wheel sensor data only.
TROUBLE JUDGEMENT CONDITIONS
M.U.T.-III judges the trouble when the periodically sent data from steering wheel sensor
cannot be received.
PROBABLE CAUSES
- Damaged harness wires and connectors
- Power supply circuit malfunction of the steering wheel sensor
- Malfunction of the steering wheel sensor
|
STEP 1. Connector check: joint connector (CAN1) and steering
wheel sensor connector.
|
|
caution |
The strand end of the twist wire should be within 10 cm from
the connector. For details refer to service precautions.
|
|
|
When checking the joint connector, ensure that its wiring harness side and its short pins
are not damaged.
|
|
Q.
Is the check result normal?
|
|
Go to Step 2.
|
|
|
|
Repair the defective connector. Replace the joint connector as necessary.
|
|
|
|
STEP 2. Resistance measurement at joint connector (CAN1) and steering
wheel sensor connector.
|
|
caution |
- A digital multimeter should
be used. For details refer to service precautions.
- The test wiring harness should be used. For details refer to service precautions.
- Strictly observe the specified wiring harness repair procedure. For details refer
to service precautions.
|
|
|
(1)Disconnect joint connector (CAN1) and the steering wheel sensor connector, and
measure at the wiring harness side.
|
|
(2)Turn the ignition switch to the "LOCK" (OFF) position.
|
|
(3)
caution |
When measuring the resistance, disconnect the negative battery
terminal. For details refer to service precautions.
|
Ensure that the negative battery terminal is disconnected.
|
|
(4)Continuity between joint connector (CAN1) terminal No. 3 and steering wheel sensor
connector terminal No. 3. OK: Continuity (2 Ω
or less)
|
|
(5)Continuity between joint connector (CAN1) terminal No. 14 and steering wheel sensor
connector terminal No. 4. OK: Continuity (2 Ω
or less)
|
|
Q.
Is the check result normal?
|
|
<All the resistances measure 2 Ω
or less>
Power supply
to the steering wheel sensor may be suspected. Diagnose the steering wheel sensor.
|
|
|
|
NO : <Either or all of the resistances measure more than 2 Ω>
Repair
the wiring harness between joint connector (CAN1) and the steering wheel sensor connector.
|
|
|