Active Stability Control System (ASC)
DTC C1608 Implausible diagnosis data
CAUTION:
- If there is any problem in the CAN bus lines, an incorrect DTC may be set. Prior to this diagnosis, diagnose the CAN bus lines CAN Bus Line Diagnostics Flow.
- Whenever ECU is replaced, ensure that the CAN bus lines are normal.
- When the hydraulic unit (integrated with ASC-ECU) is replaced, always carry out the calibration of the steering wheel sensor, the G and yaw rate sensor and brake fluid pressure sensor (Refer to Active Stability Control System (ASC) , Active Stability Control System (ASC) and Active Stability Control System (ASC) ).
OPERATION
The ASC-ECU stores diagnostic trouble codes and failure information in the EEPROM*.
ASC-ECU (EEPROM*)contains the power supply circuit (terminal No.2).
NOTE:
*:EEPROM (Electrical Erasable and Programmable ROM)
DTC SET CONDITIONS
- This DTC 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 DTC is set.
- This DTC may occur when ASC-ECU power supply shutdown or drop between ASC-ECU is writing a data to the EEPROM.
PROBABLE CAUSES
- Disconnection of the ASC-ECU connector or the battery terminal when the ignition switch is ON
- Loose battery terminal
- Abnormality in battery
- Damaged wiring harness and connectors
- ASC-ECU malfunction
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A
- MB991997: ASC check harness
STEP 1.Using scan tool MB991958, diagnose the CAN bus line.
Use scan tool to diagnose the CAN bus lines.
Q. Is the check result normal?
YES Go to Step 3.
NO Repair the CAN bus lines CAN Bus Line Diagnostics Flow).
On completion, and then go to Step 2.
STEP 2. Diagnostic trouble code recheck after resetting CAN bus lines
Q. Is DTC C1608 set?
YES Go to Step 3.
NO The procedure is complete.
STEP 3. Battery check
Battery Test.
Q. Is the battery in good condition?
YES Go to Step 5.
NO Go to Step 4.
STEP 4. Charging system check
Output Current Test.
Q. Is the charging system in good condition?
YES Replace the battery. Then go to Step 11.
NO Repair or replace the charging system component(s).
STEP 5. Voltage measurement at the A-51 ASC-ECU connector
(1)Disconnect the connector, connect special tool MB991997 to the harness-side connector, and measure the voltage at the special tool connector side.
NOTE:
Do not connect the special tool MB991997 to ASC-ECU.
(2)Measure the voltage between the terminal No.2 and the body ground.
OK: Approximately system voltage
Q. Is the check result normal?
YES Go to Step 7.
NO Go to Step 6.
STEP 6. Connector check: A-51 ASC-ECU connector
Q. Is the check result normal?
YES The open or short circuit may be present in the power supply circuit. Repair the wiring harness between the A-51 ASC-ECU connector terminal No.02 and fuse No.17.
NO : Repair the defective connector.
STEP 7. Resistance measurement at A-51 ASC-ECU connector
(1)Disconnect the ASC-ECU connector, connect special tool ASC check harness (MB991997) to the harness-side connector, and then measure the resistance at the special tool connector side.
NOTE:
Do not connect the special tool ASC check harness (MB991997) to ASC-ECU.
(2)Resistance between the terminal No.16 and the body ground, and between the terminal No.47 and the body ground
OK: Continuity exists (2 ohms or less)
Q. Is the check result normal?
YES Go to Step 9.
NO Go to Step 8.
STEP 8. Connector check: A-51 ASC-ECU connector
Q. Is the check result normal?
YES An open circuit may be present in the ground circuit. Repair the wiring harness between the A-51 ASC-ECU terminal No.16 and body ground, and between the A-51 ASC-ECU terminal No.47 and body ground.
NO : Repair the defective connector.
STEP 9. Check whether the DTC is reset.
(1)Erase the DTC.
(2)Drive the vehicle at 12mph (20 km/h) or higher.
NOTE:
The ABS warning light does not turn OFF in some cases unless the vehicle runs at 12mph
(20 km/h) or higher.
Q. Is DTC C1608 set?
YES Replace the hydraulic unit (integrated with ASC-ECU) (Refer to Active Stability Control System (ASC)).
Then go to Step 10.
NO Go to Step 11.
STEP 10. Check whether the DTC is reset.
(1)Erase the DTC.
(2)Drive the vehicle at 12mph (20 km/h) or higher.
NOTE:
The ABS warning light does not turn OFF in some cases unless the vehicle runs at 12mph
(20 km/h) or higher.
Q. Is DTC C1608 set?
YES Return to Step 1.
NO Go to Step 11.
STEP 11. Check the other DTCs.
(1)Erase the DTC.
(2)Drive the vehicle at 12mph (20 km/h) or higher.
NOTE:
The ABS warning light does not turn OFF in some cases unless the vehicle runs at 12mph
(20 km/h) or higher.
Q. Is any DTC set?
YES Carry out the applicable troubleshooting for the DTC (Refer to Active Stability Control System (ASC)).
NO The procedure is complete.