Code No.B1168 ACC system
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- If diagnosis code No. B1168 is set, always diagnose the CAN bus lines.
- Before replacing ECU, ensure that the communication circuit is normal.
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DIAGNOSTIC FUNCTION
If the output power supply status is different from the engine switch status information received from ETACS-ECU via CAN, KOS&OSS-ECU sets diagnosis code No.B1168. At the same time, KOS&OSS-ECU displays the power supply system error warning to the combination meter, and flashes the indicator of engine switch in orange.
JUDGEMENT CRITERIA
Check Conditions
- The terminal voltage of IOD and +B is between 10 and 16 V.
Judgement Criterion
- Any of the following conditions is met, and 2 seconds or more have elapsed.
- The engine switch status information received from ETACS-ECU is "ACC" when the power supply mode is at OFF.
- The engine switch status information received from ETACS-ECU is "OFF" when the power supply mode is at ACC.
PROBABLE CAUSES
- Malfunction of the CAN bus line
- Damaged wiring harness or connector (short to earth or short to power supply or open circuit in ACC line)
- Malfunction of ACC relay
- Malfunction of KOS&OSS-ECU
- Malfunction of ETACS-ECU
DIAGNOSIS PROCEDURE
STEP 1. M.U.T.-III CAN bus diagnostics
After performing the forced power supply output (Refer to 
) IG-ON using the M.U.T.-III, diagnose the CAN bus line.
Q.
Is the check result normal?
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting ).
STEP 2. ACC relay check
Check that the ACC relay works normally (Refer to ).
Q.
Is the check result normal?
Go to Step 3.
Replace the ACC relay.
STEP 3. Voltage measurement at ACC relay connector (ACC line)
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Turn the engine switch from "LOCK" (OFF) position to "ON" position.
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(3)Measure the voltage between the ACC relay connector (ACC line) and the body earth.
OK: System voltage
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(4)Turn the engine switch from "ON" position to "LOCK" (OFF) position.
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(5)Measure the voltage between the ACC relay connector (ACC line) and the body earth.
OK: 1 V or less
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Q.
Is the check result normal?
Go to Step 5.
Go to Step 4.
STEP 4. Check of short to power supply, short to earth or open circuit in ACC line between the KOS&OSS-ECU connector and the ACC relay connector
Q.
Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).
Repair the connector(s) or wiring harness.
STEP 5. Check of open circuit in earth line between the ACC relay connector and the body earth
Q.
Is the check result normal?
Go to Step 6.
Repair the wiring harness.
STEP 6. Voltage measurement at ACC relay connector (ACC line)
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Measure the voltage between the ACC relay connector (power supply line) and the fusible link connector.
OK: System voltage
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Q.
Is the check result normal?
Go to Step 8.
Go to Step 7.
STEP 7. Check of short to earth or open circuit in power supply line between the fusible link connector and the ACC relay connector
Q.
Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).
Repair the connector(s) or wiring harness.
STEP 8. Voltage measurement at ETACS-ECU connector (ACC line)
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Turn the engine switch from "LOCK" (OFF) position to "ON" position.
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(3)Measure the voltage between the ETACS-ECU connector (ACC line) and the body earth.
OK: System voltage
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(4)Turn the engine switch from "ON" position to "LOCK" (OFF) position.
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(5)Measure the voltage between the ETACS-ECU connector (ACC line) and the body earth.
OK: 1 V or less
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Q.
Is the check result normal?
Go to Step 9.
Repair the wiring harness, ACC line between the ETACS-ECU connector and the fusible link.
STEP 9. M.U.T.-III other system data list
Operate the engine switch to change the power supply mode, and check that the data list display of ETACS-ECU is changed.
- When power supply mode is OFF.
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ETACS-ECU data list
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Item No.
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Item name
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Normal condition
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29
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Ignition switch(ACC)
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OFF
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- When power supply mode is ON.
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ETACS-ECU data list
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Item No.
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Item name
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Normal condition
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29
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Ignition switch(ACC)
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ON
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- When power supply mode is ACC.
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ETACS-ECU data list
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Item No.
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Item name
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Normal condition
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29
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Ignition switch(ACC)
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ON
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OK: Normal conditions are displayed for the items.
Q.
Are the check result normal?
YES 
: Go to Step 10.
Go to Step 11.
STEP 10. Check whether the diagnosis code is set again.
Check again if the diagnosis code is set in the KOS&OSS-ECU.
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(1)Erase the diagnosis code.
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(2)Turn the engine switch from "LOCK" (OFF) position to "ON" position.
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(3)On completion, check that the diagnosis code is set again.
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Q.
Is the diagnosis code set?
Replace the ETACS-ECU (Refer to GROUP 54A - ETACS-ECU ).
Intermittent malfunction is suspected (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
STEP 11. Check whether the diagnosis code is set again.
Check again if the diagnosis code is set in the KOS&OSS-ECU.
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(1)Erase the diagnosis code.
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(2)Turn the engine switch from "LOCK" (OFF) position to "ON" position.
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(3)On completion, check that the diagnosis code is not set again.
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Q.
Is the diagnosis code set?
Replace the KOS&OSS-ECU and register the chassis number (Refer to ).
Intermittent malfunction is suspected (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).