ASC
DTC C2116: Abnormality in power supply voltage in pump motor
CAUTION:
^ If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines.
^ 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.
CIRCUIT OPERATION
^ ASC-ECU contains the power supply circuit (terminal No.1) for the pump motor. The pump motor is energized by the motor switch, which is incorporated in ASC-ECU.
^ The pump motor switch, which is incorporated in ASC-ECU, is always off unless the motor and solenoid valve check is activated when the vehicle is started.
^ ASC-ECU activates the pump motor by turning on the ECU built-in pump motor switch.
DTC SET CONDITIONS
This diagnostic trouble codes will be set under the cases below:
^ When the power supply voltage of the pump motor, which is not in operation, is abnormally low for a prolonged period
^ When the power supply voltage of the pump motor, which is not in operation, is abnormally high for a prolonged period
PROBABLE CAUSES
Current trouble
^ Fusible link malfunction
^ Damaged wiring harness and connectors
^ Abnormality in battery or generator
^ ASC-ECU malfunction
Past trouble
^ Carry out diagnosis with particular emphasis on wiring harness and connector failures between the power supply circuit (A-02 ASC-ECU connector terminal No. 1) to the ASC-ECU motor and the ground circuit (A-02 ASC-ECU connector terminal No.16 and 47). For diagnosis procedures, refer to How to treat past trouble.
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
^ MB991997: ASC check harness
STEP 1. M.U.T.-III CAN bus diagnostics
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. On completion, go to Step 2.
STEP 2. Diagnostic trouble code recheck after resetting CAN bus lines
Q: Is DTC C2116 set?
YES: Go to Step 3.
NO: The procedure is complete.
STEP 3. Fusible link check: Check the fusible link No.26.
Q: Is the check result normal?
YES: Go to Step 5.
NO: Go to Step 4.
STEP 4. Resistance measurement at A-02 ASC-ECU connector
1) Removal the fusible link No.26.
2) Disconnect the connector, connect special tool MB991997 to the harness-side connector, and measure the resistance at the special tool connector side.
NOTE: Do not connect the special tool MB991997 to ASC-ECU.
3) Resistance between the terminal No.1 and the body earth.
OK: No continuity
Q: Is the check result normal?
YES: Replace the fusible link No.26.
NO: Repair the harness between the fusible link No.26 and A-02 ASC-ECU connector terminal No.1. Then replace the fusible link No.26.
STEP 5. Battery check
Refer to Battery Test.
Q: Is the battery in good condition?
YES: Go to Step 6.
NO: Charge or replace the battery.
STEP 6. Charging system check
Refer to Output Current Test.
Q: Is the charging system in good condition?
YES: Go to Step 7.
NO: Repair or replace the charging system component(s).
STEP 7. Voltage measurement at the A-02 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) Turn the ignition switch to the ON position.
3) Measure the voltage between the terminal No.1 and the body ground.
OK: Approximately battery voltage
Q: Is the check result normal?
YES: Go to Step 9.
NO: Go to Step 8.
STEP 8. Connector check: A-02 ASC-ECU connector
Q: Is the check result normal?
YES: The open circuit may be present in the solenoid valve power supply circuit. Repair the wiring harness between the A-02 ASC-ECU connector terminal No.1 and the fusible link No.26.
NO: Repair the defective connector.
STEP 9. Resistance measurement at A-02 ASC-ECU connector
1) Disconnect the connector, connect special tool MB991997 to the harness-side connector, and measure the resistance at the special tool connector side.
NOTE: Do not connect the special tool MB991997 to ASC-ECU.
2) Resistance measurement between the terminal No.16 and body ground, and between the terminal No.47 and body ground.
OK: Continuity exists (2 ohms or less)
Q: Is the check result normal?
YES: Go to Step 11.
NO: Go to Step 10.
STEP 10. Connector check: A-02 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-02 ASC-ECU terminal No. 16 and the body ground, and between the A-02 ASC-ECU terminal No. 47 and the body ground.
NO: Repair the defective connector.
STEP 11. Check whether the diagnostic trouble code is reset.
1) Erase the diagnostic trouble code.
2) Drive the vehicle at 12 mph (20 km/h) or more.
NOTE: The ABS warning light does not turn OFF in some cases unless the vehicle runs at 12 mph (20 km/h) or higher.
Q: Is DTC C2116 set?
YES: Replace the ASC-ECU.
NO: Intermittent malfunction.