Code No.74: G and Yaw Rate Sensor Communication Line Fault
caution |
If there is any problem in the CAN bus lines, an
incorrect diagnosis code may be set. Diagnose the CAN bus lines before the
diagnosis codes (Refer to GROUP 54D, CAN bus-line diagnostic flow ).
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![](../../../img/35/AC608371AA00ENG.png)
![](../../../img/35/AC607564BN00ENG.png)
![](../../../img/35/AC607571BN00ENG.png)
![](../../../img/35/AC607567AE00ENG.png)
![](../../../img/35/AC607609AE00ENG.png)
OPERATION
The ASTC-ECU gathers information regarding lateral and
longitudinal gravities and yaw rate, through the CAN bus line from the G and
yaw rate sensor.
DIAGNOSIS CODE SET CONDITIONS
Diagnosis code No. 74 is set when
the ASTC-ECU cannot receive the CAN data from the G and yaw rate sensor.
PROBABLE CAUSES
The most likely causes for these diagnosis codes
to set are:
- Damaged wiring harness or connector
- Malfunction of the G and yaw rate sensor
- Malfunction of the ASTC-ECU
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STEP 1. M.U.T.-III CAN bus diagnostics
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caution |
Before connecting or disconnecting the M.U.T.-III,
turn the ignition switch to the "LOCK" (OFF) position.
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(1)Connect M.U.T.-III to the 16-pin diagnosis
connector.
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(2)Turn the ignition switch to the "ON" position.
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(3)Diagnose the CAN bus line.
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(4)Turn the ignition switch to the "LOCK" (OFF)
position.
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Q.
Is the check result normal?
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Go to Step 3.
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Repair the CAN bus line (Refer to
GROUP 54D, CAN bus line Diagnostic flow ). Then go to Step 2.
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STEP 2. Check whether the diagnosis code is reset.
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caution |
Before connecting or disconnecting the M.U.T.-III,
turn the ignition switch to the "LOCK" (OFF) position.
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(1)Turn the ignition switch to the "ON" position.
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(2)Erase the diagnosis code.
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(3)Turn the ignition switch to the "LOCK" (OFF)
position.
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(4)Turn the ignition switch to the "ON" position.
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(5)Check if the diagnosis code is set.
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(6)Turn the ignition switch to the "LOCK" (OFF)
position.
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Go to Step 3.
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The
procedure is complete.
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STEP 3. Check the M.U.T.-III data list.
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(1)Disconnect the G and yaw rate sensor connector, and remove
the G and yaw rate sensor.
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(2)Connect the G and yaw rate sensor connector to the G and
yaw rate sensor.
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(3)Turn the ignition switch to the "ON" position.
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(4)Check that the data list output changes within the
following range when the G and yaw rate sensor is
slanted.
- Item 19: G sensor output (Front and rear)
OK: Indication varies between -14.7 and 14.7
m/s2
- Item 20: G sensor output (Left and right)
OK: Indication varies between -14.7 and 14.7
m/s2
OK: Indication varies between -50 and 50
deg/s
- Item 22: G sensor output 1
OK: Indication varies between -14.7 and 14.7
m/s2
- Item 23: G sensor output 2
OK: Indication varies between -14.7 and 14.7
m/s2
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Q.
Is the check result normal?
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Go to Step 9.
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Go to Step 4.
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STEP 4. Check G and yaw rate sensor connector D-18, intermediate
connector D-228, junction block connector D-403 and junction block
connector D-405 for loose, corroded or damaged terminals, or terminals
pushed back in the connector.
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Q.
Is the check result normal?
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Go to Step 5.
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Repair or replace the damaged
component(s). Then go to Step 10.
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STEP 5. Check fuse No. 2.
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Q.
Is the check result normal?
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Go to Step 6.
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Replace fuse No. 2. Then go to
Step 10.
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STEP 6. Check the power supply circuit at G and yaw rate sensor
connector D-18.
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(1)Disconnect G and yaw rate sensor connector D-18, and
measure at the harness side.
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(2)Turn the ignition switch to the "ON" position.
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(3)Measure voltage between terminal 1 and
earth. OK: System voltage
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Q.
Is the check result normal?
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Go to Step 8.
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Go to Step 7.
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STEP 7. Check the junction block connector D-403.
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(1)Disconnect junction block connector D-403, and measure at
the junction block side.
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(2)Turn the ignition switch to the "ON" position.
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(3)Measure voltage between terminal 6 and
earth. OK: System voltage
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Q.
Is the check result normal?
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Repair the wiring harness between
the junction block connector D-405 and the G and yaw rate sensor connector
D-18. Then go to Step 10.
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Repair the wiring harness between
the junction block connector D-403 and the ignition switch (IG1). Then go
to Step 10.
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STEP 8. Check the earth circuit at G and yaw rate sensor connector
D-18.
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(1)Disconnect G and yaw rate sensor connector D-18, and
measure at the harness side.
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(2)Measure the resistance between terminal 4 and
earth. OK: Continuity exists (2 Ω or less)
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Q.
Is the check result normal?
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Repair the wiring harness between
G and yaw rate sensor connector D-18 and earth. Then go to Step
10.
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Go to Step 9.
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STEP 9. Check whether the diagnosis code is reset.
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(1)Turn the ignition switch to the "ON" position.
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(2)Erase the diagnosis code.
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(3)Turn the ignition switch to the "LOCK" (OFF)
position.
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(4)Turn the ignition switch to the "ON" position.
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(5)Check if the diagnosis code is set.
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(6)Turn the ignition switch to the "LOCK" (OFF)
position.
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Replace the G and yaw rate
sensor. Then go to Step 10.
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It can
be assumed that this malfunction is intermittent. Refer to GROUP 00, How to
Use Troubleshooting/Inspection Service Points - How to Cope
with Intermittent Malfunction .
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STEP 10. Check whether the diagnosis code is reset.
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(1)Turn the ignition switch to the "ON" position.
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(2)Erase the diagnosis code.
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(3)Turn the ignition switch to the "LOCK" (OFF)
position.
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(4)Turn the ignition switch to the "ON" position.
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(5)Check if the diagnosis code is set.
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(6)Turn the ignition switch to the "LOCK" (OFF)
position.
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Repeat the troubleshooting from
Step 1.
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The
procedure is complete.
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