If there is any problem in the
CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, diagnose the
CAN bus lines (Refer to GROUP 54C, Trouble code diagnosis ).
If the ABS-ECU connector is disconnected or the battery terminal is disconnected
when the ignition switch is ON, this diagnosis code may be set.
Since the failure information stored in the past is erased after this diagnosis
is carried out, reproduce the state of malfunction.
OPERATION
The ABS-ECU stores diagnosis codes and failure information in the EEPROM*.
note
*:EEPROM (Electrical Erasable and Programable ROM)
DIAGNOSIS CODE SET CONDITIONS
This diagnosis code is set when the failure information stored in the EEPROM is not reliable.
The failure information stored in the past is not output, and only this diagnosis code is set.
PROBABLE CAUSES
Disconnection of the ABS-ECU connector or the battery terminal when the ignition
switch is ON
Loose battery terminal
Abnormality in battery
Damaged wiring harness and connectors
ABS-ECU malfunction
DIAGNOSIS PROCEDURE
STEP 1. M.U.T.-III CAN bus diagnosis
Use scan tool to diagnose the CAN bus lines.
Q.
Is the check result normal?
Go to Step 3.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnosis table ).
On completion, go to Step 2.
STEP 2. Diagnosis code recheck after resetting CAN bus lines
Q.
Is the diagnosis code No. C1608 set?
Go to Step 3.
The procedure is complete.
STEP 3. Battery check
Refer to GROUP 54A - Battery Test .
Q.
Is the battery in good condition?
Go to Step 5.
Go to Step 4.
STEP 4. Charging system check
Refer to GROUP 16 - Charging System .
Q.
Is the charging system in good condition?
Replace the battery. Then go to Step 9.
Repair or replace the charging system component(s).
STEP 5. Voltage measurement at the A-02 ABS-ECU connector
(1)Disconnect the ABS-ECU connector, connect special tool ABS check harness (MB991974) to
the harness-side connector, and then measure the resistance at the special tool connector side.
note
Do not connect the special tool ABS check harness (MB991974) to ABS-ECU.
(2)Turn the ignition switch to the ON position. (3)Measure the voltage between the terminal No. 26 and the body earth. OK: Battery voltage
Q.
Is the check result normal?
Go to Step 6.
Go to Step 7.
STEP 6. Connector check: A-02 ABS-ECU connector
Q.
Is the check result normal?
The open or short circuit may be present in the power supply circuit. Repair the
wiring harness between the A-02 ABS-ECU connector terminal No. 26 and the fusible link No. 27.
NO : Repair the defective connector.
STEP 7. Resistance measurement at A-02 ABS-ECU connector
(1)Disconnect the ABS-ECU connector, connect special tool ABS check harness (MB991974) to
the harness-side connector, and then measure the resistance at the special tool connector side.
note
Do not connect the special tool ABS check harness (MB991974) to ABS-ECU.
(2)Resistance between the terminal No. 1 and the body earth. OK: Continuity exists (2 Ω or less)
Q.
Is the check result normal?
Go to Step 9.
Go to Step 8.
STEP 8. Connector check: A-02 ABS-ECU connector
Q.
Is the check result normal?
An open circuit may be present in the ground circuit. Repair the wiring harness
between the A-02 ABS-ECU connector terminal No.14 and the body earth.
NO : Repair the defective connector.
STEP 9. Check whether the diagnosis code is reset.
(1)Erase the diagnosis code.
(2)Turn the ignition switch to the "LOCK" (OFF) position.
(3)Turn the ignition switch to the "ON" position.
Q.
Is any diagnosis code set?
YES (Diagnosis code C1608 is set) : Replace the ABS-ECU.
YES (Diagnosis code other than C1608 is set) : Carry out the applicable troubleshooting for the diagnosis code.
)
)
)
Go to Step 3.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnosis table 
).
On completion, go to Step 2.)
)